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Science Notes 2005
Waves
Mechanical Waves
Are described as motions that carry energy from one place to another. Energy moves along
with the wave but matter does not. It disturbs matter with vibration and transfer energy.
Amplitude
crest
Wavelength (
)
Origin
Trough
Amplitude: -the height of the crest above the level where no waves are moving. Amplitude to
the origin to the crest equals the origin to the trough.
Wavelength-measured from crest to crest or trough to trough.
Frequency-the number of complete wave cycles that pass any one point in one second. F (Hz).
1 hertz equals one cycle per a second.
Speed-the speed of a wave depends on the material that makes up the medium. Eg. Air, water
does not depend on frequency or amplitude. Its symbol (m/s) It is calculated by
Wave Speed = frequency (Hz) x wavelength
Frequency = 1/Period
Period = 1/Frequency
There are two types of waves, the first one, longitudinal or compression waves. The second,
transverse waves.
Direction of Wave
This wave is a transverse wave because particles vibrate at right angles to the direction of the
wave. Water and light waves are transverse waves.
Compression
Rarefraction
Compression
Rarefraction
Particles vibrate in the same direction as the wave is travelling. The particles of the medium
vibrate forwards and backwards acting like coils in a spring as they are squeezed together and
then stretched out. Sound waves are longitudinal waves.
The compressions and rarefractions making up sound waves have the same frequency as the
vibrating object. Sound waves are longitudinal waves. They transfer energy. Sound travels
through solids, liquids and gases. It will not travel in a vacuum. The speed of sound in air is
about 340m/s. It travels four times as fast in water and fifteen times as fast in steel.
The major differences between sound and light energy are 1) the type of wave. Ie transverse
or longitudinal and 2) sound energy will not travel thorough a vacuum but light will.
Sound
It is a form of energy that is produced by vibrating objects. The energy produced by the
vibration is transferred to the air. Air particles start vibrating and pass the vibrations on to
other air particles. The vibrations cause energy to travel as waves through the air away from
the object. Wavelength is the distance between two high-pressure areas. Amplitude is the
distance air molecules move forwards and backwards. Louder sounds make air molecules
vibrate with greater amplitude. Frequency is the number of sound waves produced each
second. It is measured in Hz. High frequency produce high-pitched sounds and vice versa.
The decibel scale (dB) is used to measure sound levels.
Echoes
When sound waves hit a hard surface they are reflected and you hear an echo. This can
determine how far an object is. Ships use sonar to measure the depth of the seabed or for
fishing. Animals such as bats and dolphins use ultrasonic waves to navigate and to locate
food.
Electromagnetic Waves
Electromagnetic waves do not travel on particles but on varying electric and magnetic fields.
The types of radiation listed here are from highest wavelength to lowest.
Name
Wavelengths
Frequency (Hz) Source
Detectors
Uses
(m)
Radio and
> 1 x 10-1
< 3 x 109
Electric
Dish shaped
Radio and
TV
circuits and
aerials and
Television,
transmitting
satellites
MRI scanners
aerials
Microwave
1 x 10-3 - 1 x 10- 3 x 109 - 3 x
Electric
Dish shaped
Microwave
1
1011
circuits and
aerials and
ovens, radar.
transmitting
satellites
aerials
Infra-red
7 x 10-7 - 1 x 10- 3 x 1011 - 4 x
Electric
Heat sensors
Dry paint
3
14
10
Radiator
in our skin,
quickly on
thermopiles
cars, treat
and special
muscular pain
photographs.
Optical
4 x 10-7 - 7 x 10- 4 x 1014 - 7.5 x
Sun
Eyes
Astronomy,
7
1014
photography,
optic fibres
UV
1 x 10-8 - 4 x 10- 7.5 x 1014 - 3 x
Mercury Lamp Fluorescence
To show
7
1016
invisible
signatures on
bank books
-11
16
X-ray
1 x 10 - 1 x
3 x 10 - 3 x
X-ray tube
Film
CT scanners
10-8
1019
Gamma-ray
< 1 x 10-11
> 3 x 1019
Radioactive
Source
Geiger
counters
PET scanners
Motion
Units in standard index ie. metres, kilograms, seconds
Two types of quantities: vectors - have size, direction eg. Force.
scalars - have size only eg. Mass
Distance - how far an object travels, no direction.
Displacement – how far an object travels from its starting point in straight line, has direction.
Distance/Time Graphs can represent the distance travelled by an object in a given time.
Slope of time gives us speed. Therefore steeper slope = greater speed.
Speed of objects can be investigated using a ticker timer, which produces 50 dots/sec on a
tape. Ie. Space between each pair of adjacent dots = 0.02 sec measure distance – hence
calculate speed using d/t.
Speed and Velocity
Speed is distance/time. Speed is a scalar – has no direction. The average speed can be worked
out by getting the total distance/ total time.
Speed can be instantaneous ie. Speed at a given point in time usually worked out by using
slope or gradient.
Velocity is the same as speed however, direction is taken into account.
V=S
v = velocity in m/s
t = time in secs
T
s = displacement in m
Newton’s Laws
First law states that an object will not change its state of motion unless an unbalanced force
acts on it.
The second law states that when an object is accelerated, the acceleration depends on the
mass of the object and the size of the force applied to it.
Ie. Force = Mass X Acceleration
The third law states that for every action there is an equal and opposite reaction.
Newton’s Equations for Motion
Velocity (v) = Initial Speed (u) + Acceleration (a) X Time (t)
Displacement (s) = Initial Speed (u) X Time (t) + ½ X Acceleration (a) X Time^2 (t^2)
Velocity^2 (v^2) = Initial Speed^2 (u^2) + 2 X Acceleration (a) X Displacement (s)
If an object is falling towards the earth then the equations become:
v = u + 9.8t
s = ut + 4.9t^2
v^2 = u ^2 + 19.6s
If an object is thrown vertically upwards, then gravity opposes its velocity. The equations will
become:
v = u – 9.8t
s = ut – 4.9t^2
v^2 = u^2 – 19.6s
To convert from metres per a second to kilometres per an hour multiply by 3.6.
Electrical Energy
Electricity is a form of energy and is useful because it can easily be converted into other
forms of energy, is easy to transport or move from place to place and is easy to generate. The
two types of electricity are static electricity (trapped electricity charges) and current
electricity (flow of electrons moving through a conductor it can be either direct current or
alternating current)
A circuit is a path for electrons to flow through. The path is from a power sources negative
terminal to the positive terminal.
A conductor is a material that allows electrical current to pass easily through.
Current is measured in series.
Voltage is measured in parallel.
Voltage measures a drop in potential between 2 points. Voltage is like the force that pushes
the electricity around the circuit. Current is the actual size of the electron flow.
Total Resistance: Series – R1 + R2
Parallel – 1/R1 + 1/R2 = 1/Total resistance
In a series circuit the same current flows through each part of the circuit. In a parallel circuit
the circuit divides when it comes to a junction. When the two branches have the same
resistance the same current flows through each branch, Figure 1. When the two branches have
different resistances the bigger current flows through the branch with the smaller resistance,
Figure 2.
Figure 1
Figure 2
Circuit Symbols
Light Energy
Reflection
When waves hit a solid object it may be reflected. The Law of Reflection states ‘the angle of
incidence equals the angle of reflection’. If a ray of light approaches at right angles, it is
reflected back along its own path. The image seen in a mirror is a virtual image as light only
appears to come from the image in the mirror.
Refraction
This is the bending of light as it passes from one medium to a medium of different density
when the incident is at any angle other than 90 degrees to the surface. The bending of light
rays is due to a change in the speed of light. When light ray enters a different medium at right
angles to the surface, its speed changes but not its direction. If a ray moves into a medium of
greater optical density, it is bent towards the normal. If a ray moves into an object of less
optical density, it is bent away from the normal.
Diffraction
If waves pass through small gaps in barriers they spread out. This is diffraction. Diffraction is
most obvious when the width of the gap is the same size as the wavelength.
Interference
When one wave meets another wave interference occurs. They can either cancel each other
out and appear flat (destructive interference) or if two crests meet they become twice as high
or if two troughs meet, twice as deep (constructive interference).
Lenses
A lens is a curved transparent material, which controls the direction of light by refraction.
Convex lenses-they are called converging lenses and are thicker at the centre than the edge.
All rays parallel to the principal axis refract to a principal focus.
Concave lenses-they are also called diverging lenses and are thinner at the centre than the
edge. Rays parallel are refracted so that they appear to come from a point (principal focus).
White Light
White light consists of red, yellow, orange, green, blue, violet and indigo. Separation of
colours is known as dispersion. White light can split by passing through a triangular glass
prism. The colours of violet end are refracted more than colours at the red end of the
spectrum. When sunlight, passes through rain or mist, it is refracted and dispersed into
colours of the spectrum. This forms a rainbow.
Scattering
White light from the sun hits air molecules and dust particles. Some of the colours that make
up white light are absorbed whilst others are scattered ie. Blue. The sky at sunrise and sunset
has shades of red because the different angle of the sun means that the blue end of the
spectrum is absorbed and the red is scattered.
Eye
It is roughly shaped like a sphere. There are three tissue layers:
Outer layer is the sclera is extremely tough. The muscles of the eye are attached to the sclera
and this allows eye movement. The sclera is white in colour, except at the front where it
forms the transparent cornea. The cornea allows light to enter the eye.
Middle layer is the choroid coat. The choroid has a rich supply of blood vessels and is deeply
coloured with melanin (a black pigment). The choroid contains most of the blood vessels that
nourish the eye. The melanin in the choroid absorbs any stray light reflected inside the eye.
This prevents blurring.
Inner layer is the retina. The retina contains two kinds of light-sensitive cells: rods and cones.
Rods are especially sensitive to dim light but react to all wavelengths of the visible spectrum.
They cannot detect colour. Cones respond best to narrower parts of the visible spectrum of
light. They are sensitive to colours and details in bright light. Cones cannot detect very dim
light.
Myopia (short sightedness) occurs when a distant object looks blurred because the image
comes into focus before it reaches the retina. Myopia can be corrected with a minus lens,
which moves the focus farther back.
Hyperopia (long sightedness) occurs when a close object looks blurred because the image
doesn't come into focus before it gets to the retina.
32
Radioactivity
Isotopes, which are radioactive, are called radioisotopes. Radioisotopes decay to form
isotopes of other elements
The half-life of a radioisotope is the time taken for half of the atoms to decay. Radiometric
Dating can be used to find the age of an object if it contains a radioisotope.
Radiation is received under normal circumstances. Unstable isotopes are called radioisotopes
and decay giving off high-energy radiation and bring different atoms. The radiation is in three
forms.
Radiation
Description
Symbol
Charge
Alpha
Two protons. Two
+ Positive
neutrons. Helium
nucleus. Thrown out
of a nucleus of
unstable
radioisotopes.
Beta
Negatively charged
- Negative
electrons. e-1
Gamma
High frequency.
No charge
Electromagnetic
radiation. Note: it
can also and usually
does accompany
alpha and beta part.
Gravitational Force
Gravity is a force of attraction that exists between all objects in the universe that have mass.
The gravitational force as stated in Newton’s Laws of Gravitation depends on:
mass => greater mass => greater gravitational force.
Distance => the closer the objects are, the greater the gravitational forces are.
Mass is the amount of matter in an object.
Weight is the force exerted by a body under influence of gravity.
The new equation is Weight force (F) = Mass (M) X Acceleration due to gravity (G)
Atomic Theory
Structure of Atoms-Atoms is made up of a central core called the nucleus and an electron
cloud, which surrounds it. The nucleus is made up of protons and neutrons, protons have a
positive charge and neutrons no charge. The negative electrons are attracted to the central past
the nucleus. The nucleus is held together by nuclear forces. These are strong forces which act
to prevent the electrostatic (attraction and repulsion) from breaking the nucleus apart. The
number of protons in the nucleus of an atom is known as the Atomic number (z). The number
of protons plus neutrons is called the mass no. It is measure in atomic mass unit (amu).
The model of an atom is commonly used is the ‘solar system’. The electrons exist in orbits,
which are numbered in ascending order. Each orbit has a max. number of electrons.
Orbit/shell
Max no. of e
1
2
2
8
3
18
4
Atomic Structure
Max number of e- = (2n squared) (N being the principal number)
Mass No. – Atomic No. = no. of neutrons
Atomic Energy and Nuclear Energy
mass no. = no. of protons + no. of neutrons
Atomic number = number of protons
Elements – Is an pure substance which can no longer be split up by chemical means. What
makes one element different from another is the number of protons and electrons.
Isotopes - forms of the same element that behave chemically the same but have different
number of neutrons in the nucleus. The mass number of isotopes is always a whole number
whilst the mass number listed on the periodic table for an element is statistically determined
taking into consideration all isotopes of that element.
Elements
Elements are pure substances that cannot be split up into other chemicals. There are about 106
known elements. About three-quarters of the elements are in a group called metals. One-sixth
of the elements are called non-metals. The rest sometimes behave as metals and sometimes as
non-metals and are known as semi-metals. Elements are made up of particles called atoms
and molecules. The difference between an atom and a molecule is that an atom is a single
existing particle eg. N, while a molecule is the smallest possible way a compound or element
can exist eg. H2O, O2, etc.
Relationships
The active or alkaline metals are the first columns of the periodic table. The metals in the first
column of the periodic table are very reactive with other substances because they have a
single electron in their outermost shell, just waiting to be stripped off to form a complete shell
in some other atom. All the alkali metals have to be stored under oil except lithium as they
react quickly with oxygen in the air and vigorously with water. They are unusual for metals as
they are very soft and light and they have low melting and boiling points. Going across the
groups the reactivity decreases while the metallic properties increase until the non-metals.
The transition metals are very hard, with high melting points and boiling points. Moving from
left to right across the periodic table, the five d orbitals become more filled. The d electrons
are loosely bound, which contributes to the high electrical conductivity and malleability of the
transition elements. The transition elements have low ionisation energies.
Noble gas refers to any element of the group of six-element in-group VIII of the periodic
table. Unlike most elements, the noble gases are monoatomic. The atoms have stable
configurations of electrons. Therefore under normal conditions they do not form compounds
with other elements. They were generally called inert gases until about 1962 when xenon
tetrafluoride, XeF4, was produced in the laboratory.
The lanthanides are located in block 5d of the periodic table. The first 5d transition element is
either lanthanum or lutetium, depending on how you interpret the period trends of the
elements. The lanthanides do not follow precise patterns of behaviour of other groups or
periods in the periodic table. The lanthanides are often found together in minerals. Along with
actinides they make up the inner transition series.
The actinide series encompasses the 14 chemical elements that lie between actinum and
nobelium on the periodic table with atomic numbers between 89 and 102 inclusive. They are
similar in characteristics to the elements of the lanthanide series. The actinides with the higher
atomic numbers are not found in nature and have short half-lives. They are all radioactive are
highly reactive and electropositive. They react with boiling water or dilute acid to release
hydrogen gas.
Compounds and Reactions
Law of Conservation of Mass
The states that matter can neither be created nor destroyed. Matter however, can be
rearranged through chemical reactions including radioactive decay. This law can only be
observed in a closed system meaning that it still applies however, products of reactions such
as gases can escape giving the appearance of a loss of matter in an open system.
Formation of Ions
When electrons are added to or removed from a neutral atom an ion is formed. Cations are
positively charged ions resulting from the subtraction of one or more electrons. Anions are
negatively charged ions resulting from the addition of one or more electrons.
Tests
Hydrogen gas- Place magnesium in test tube and cover with hydrochloric acid. Place large
test tube over top to collect gas. Light a wooden splint and hold over large test tube when you
turn it over. Observations are it becomes bubbly, metal disappears and gas given off. It will
extinguish flame and make a popping noise.
Oxygen gas-Place a small teaspoon of manganese dioxide in bottom of test tube and cover
with hydrogen peroxide. Place larger test tube to collect gas. Light wooden splint and gently
blow out so tip of splint is still glowing. Place splint into top of tube and it should relight.
Carbon dioxide gas-Place marble chips into test tube and cover with acid. Carbon dioxide gas
is denser than air and will stay in tube uncovered for a short time. Place delivery tube onto
test tube with a bung. Pour limewater into test tube to about 2 cm deep. Place other end of
delivery tube into limewater. The carbon dioxide gas will bubble into the limewater as it
forms. The limewater should turn cloudy.
Ionic bonds and Ionic compounds
Ionic compounds can only be formed through bonding metals with non-metals. The ionic
bond and is a result of the metals donating its electron/s in the outer shell to non-metals. This
causes the metal to form a positive ion and non-metal to for a negative ion. It is the
electrostatic attraction between the positive and negative ions that causes the chemical bond.
Polyatomic Group
NO3
NO2
OH
NH4
NH3
HCO3
HPO4
HPO3
CO3
CrO4
Cr2O7
SO4
SO3
PO4
PO3
Valency
-1
-1
-1
+1
+1
-1
-2
-2
-2
-2
-2
-2
-2
-3
-3
Name
Nitrate
Nitrite
Hydroxide
Ammonium
Ammonia
Hydrogen Carbonate
Hydrogen Phosphate
Hydrogen Phosphite
Carbonate
Chromate
Dichromate
Sulfate
Sulfite
Phosphate
Phosphite
Polyatomic Groups (Radicals)
These are compounds that can form an ionic bond with metal ions to make an ionic
compound. Each group has its own valency and acts like single unit when bonding.
Covalent Bonds
Formed between non-metals. These bonds are formed because atoms donate an atom each to
be shared in a bond by both atoms. Covalent bonds may be single that is they share a pair of
electrons, double bond that is they share two pairs of electrons or triple bonds that is they
share 4 pairs of electrons.
Electrolyte
An electrolyte is a solution containing an ionic compound.
Strong Electrolytes-High ion concentration and zero molecule concentration
Weak Electrolytes- Low ion concentration and high molecule concentration
Non electrolyte-Zero ion concentration and high molecule concentration.
Naming Compounds
Name
Prefix
Mono
1
Element
Valency
Fe (II)
+2
Ferrous
Di
2
Fe (III)
+3
Ferric
Tri
3
Pb
+2, +3
Tetra
4
Cu
+2, +1
Penta
5
Co
+2
Hexa
6
Zn
+3
Hepta
7
Ni
+2
Octa
8
Ag (silver) +1
Nono
9
Sn (tin)
+2
Decca
10
Al
+3
Ba
+2
Br
-1
CH3COO
-1
I
-1
Metal/Non-metal compound two elements only
1) The metallic element is named first
2) The name of the non-metal is shortened and the suffix ‘-ide’ is added to this shortened
name eg. NaCl – Sodium chloride
Metal/Non-metal compound three or more elements
1) The metallic element is named first
2) The chemical radical is named second eg. FeSO4 – Iron sulfate
Non-metal/Non-metal compounds
1) If hydrogen is present, it is named first
2) If no hydrogen, the solid non-metal is named first
3) If only two elements, name of second is shortened and suffix ‘-ide’ is added.
4) If only two elements, prefixes ‘mon-‘, ‘di-‘, etc. are used on the name of the second to
indicate how many atoms of it there are in the formula. Eg. CCl4 – Carbon tetrachloride
5) If more than two elements, first is named and this followed by the name of the radical eg.
Hydrogen Chloride
Common Compounds
Chemical Name
Acetic acid
Formula
CH3COOH
Common Name
Ethanoic acid, vinegar
Actinium
Ascorbic Acid
Barium Sulfate
Benzoic Acid
Calcium Carbonate
Calcium Hydroxide
Calcium Oxide
Calcium Sulfate
Carbonic Acid
Citric Acid
Copper Sulfate
Ethanol
Formic Acid
Glucose
Hydrochloric Acid
Lactic Acid
Lead Monoxide
Lead Tetraoxide
Magnesium Sulfate
Nitric Acid
Oxalic Acid
Potassium Hydroxide
Potassium Nitrate
Silicon Dioxide
Sodium Hydrogen Carbonate
Sodium Carbonate
Sodium Chloride
Sodium Hydroxide
Sodium Sulfate
Sulfuric Acid
Sucrose
Tartaric Acid
Ac
HC6H7O6
BaSO4
C6H5COOH
CaCO3
Ca(OH)2
CaO
CaSO4
H2CO3
C6H8O7
CuSO4
C2H5OH
Water
H2O
Malic Acid
Vitamin C
Barium Meal
Limestone, marble, calcite
Slaked Lime
Quick Lime
Gypsum (Plaster of Paris)
Soda Water
Bluestone
Ethanol
HCOOH
C6H12O6
HCl
C3H6O3
PbO
Pb3O4
MgSO4
HNO3
HOOCCOOH
KOH
KNO3
SiO2
NaHCO3
Na2CO3
NaCl
NaOH
Na2SO4
H2SO4
C12H22O11
Muriatic Acid
Oxolead
Red Lead
Epsom Salts
Caustic Potash
Saltpetre, fertiliser
Sand, quartz
Baking soda, bicarbonate of soda
Washing Soda
Common Salt
Caustic Soda
Glauber’s salt
Oil of Vitriol
Table Sugar
HOOCCH(OH)CH(OH)C
OOH
Chemical reactions
Chemical reactions are chemical changes. The initial substances are called reactants and the
final substances are called products. Chemical reactions usually are exothermic.
Acids – group of chemicals/compounds, which form H+ ions when, dissolved in water.
Examples are sulfurous acid (H2SO3), Phosphoric acid (H3PO4), Hydrogen Sulfide (H2S),
and Nitric acid (HNO3). Sour and reacts with metals, carbonates and bases.
Bases – compounds, which contain hydroxide ions (OH-) or oxide ions (O2-) in water.
Examples are Sodium Hydroxide (NaOH), Calcium hydroxide: limewater [Ca (OH)2],
Ammonium Hydroxide (NH4OH), etc. Bitter and slippery reacts with acids.
Salts are ionic compounds, which contain no oxide, hydroxide or hydrogen ions. Eg. NaCl.
Universal Indicator
Acids and bases can be distinguished using chemicals called indicators. These change colour according
to how acidic or basic a solution is. The universal indicator is made of a number of indicators and can
tell us the strength of a solution acidity or alkalinity measured in pH. 14 being the highest
alkaline and 0 being acidic.
Combustion
Combustion can be fast or slow. When fast it is referred to as burning. When slow, rusting or
respiration. This reaction is exothermic. During the combustion the elements in the fuel
combine with oxygen from the air to form new chemical compounds called oxides. This is
why combustion is also called oxidation. The equation can be summarised as
Fuel + Oxygen  CO2 + H2O + Energy
Corrosion
Chemical corrosion affects metals when their atoms give up electrons to form ions. For
example: iron + hydrochloric acid  iron chloride + hydrogen.
If we look at what happens to the iron atoms: Fe  Fe2+ + 2ePrecipitation
A chemical precipitate forms whenever an insoluble chemical compound is formed during a
reaction. Precipitates are noticeable because they ‘cloud up’ the mixture and eventually sink
to the bottom of the container, they can be separated from a mixture by filtration.
Covalent compounds like sugar, dissolve in water because the forces between sugar
molecules and water molecules are stronger than the forces between sugar molecules.
Ionic compounds like sodium chloride dissolve for the same reason, except the forces holding
the compound together are ionic lattice forces of electrostatic attraction and the compound
exists as a three-dimensional crystal lattice.
Solubility Rules
1) All compounds of the ammonium ion (NH4+), and of Alkali metal (Group IA) cations, are
soluble.
2) All nitrates and acetates (ethanoates) are soluble.
3) All chlorides, bromides and iodides are soluble EXCEPT those of silver, lead and
mercury (I).
4) All sulphates are soluble EXCEPT those of silver, lead, mercury (I), barium, strontium
and calcium.
5) All carbonates, sulfites and phosphates are insoluble EXCEPT those of ammonium and
Alkali metal (Group IA) cations.
6) All hydroxides are insoluble EXCEPT those of ammonium, barium and alkali metal
(Group I) cations.
7) All sulfides are insoluble EXCEPT those of ammonium, Alkali metal (GroupI) cations
and Alkali earth metal (Group II) cations.
8) All oxides are insoluble EXCEPT those of calcium, barium and Alkali metal (Group I)
cations; these soluble ones actually react with the water to form hydroxides.
An example of a precipitate:
Barium nitrate + Copper sulfate  ???????
According to Coulomb’s laws of electrostatics, the oppositely-charged ions will attract each
other, so in theory we could have:
1. copper ions + sulfate ions  copper sulfate
2. copper ions + nitrate ions  copper nitrate
3. barium ions + sulfate ions  barium sulfate
4. barium ions + nitrate ions  barium nitrate
Looking at the solubility rules we find that, of these four possibilities, only one will result in
an insoluble product, barium sulfate. Therefore that will be the precipitate.
Acids on Metals and Carbonates
The general equation for the reaction of acids on metals is:
Acid + Active Metal  Metallic salt + Hydrogen
Eg. Zinc + Hydrochloric Acid  Zinc sulfate + hydrogen
The equation for acids on carbonates is:
Acid + Carbonate  Salt + Carbon dioxide + Water
Eg. Hydrochloric Acid (aq) + Calcium Carbonate (s)  Calcium Chloride (aq) + Carbon
Dioxide (g) + Water (l)
Acid + Hydrogen Carbonate  “
”
Neutralisation
General Equation:
Acid + Alkali  Salt + Water
Salts are generally neutral ie. pH 7. The name of the salt is determined by acid and alkali use.
The surname of the salt is named after the acid. Acetic acid produces ______acetate.
Decomposition
Chemical decomposition occurs when chemical compounds break down into simpler
chemical forms, either simpler compounds or their constituent elements. This can be caused
by heat or electrolysis. Eg. 2H2O = H2 + O2
Thermal Decomposition
This occurs when a chemical compound is broken down into simpler chemical forms by heat.
Not all chemical compounds decompose when they are heated – some just melt and then
evaporate. These rules apply only to the compounds that do decompose when heated:

When heated 

1)
2)
3)
4)
metal carbonates decompose to form the metal oxide and carbon dioxide gas
in air, metal oxides decompose to form the metal and oxygen gas
with carbon, metal oxides decompose to form the metal and carbon dioxide
gas
 metal hydroxides decompose to form the metal oxide and water
 metal sulfates decompose to form the metal oxide and sulfur trioxide gas.
Cell Theory
Cells are the basic unit of life.
All life forms on the planet are composed of cells. They are made up of either a single
cell (unicellular) or a population of cells.
All cells come from other cells. One cell must divide to form two new cells. This is the
only way cells can reproduce.
All the chemical reactions necessary for the maintenance and reproduction of life take
place within a cell.
All living cells that are unicellular or whether they are part of a multicellular organism carry
out six vital functions for living:
 Taking in and using nutrients
 Responding to stimuli
 Growing
 Breaking down chemicals to release
energy (respiration)
 Getting rid of wastes
 Reproducing
Animal Cells
Part of Cell
Function
Cell Membrane
Holds in the liquid parts of the cell. Thus the cell membrane controls
which chemicals can enter and leave a cell, it also retains a cell’s shape.
Cytoplasm
Is mostly water and most of the cell’s chemical reactions take place in
the cytoplasm.
Mitochondria
ribosomes
Endoplasmic
Reticulum
Golgi Apparatus
Nucleus
Small dark rod-shaped objects that move around the cell to supply
energy where it is needed. The chemical reaction that supplies this
energy from the food is called respiration.
Translate instructions in the DNA to make proteins. The instructions
are carried from the DNA to the ribosomes by long nucleic-acid
molecules called messenger ribonucleic acids.
Is made up of sheetlike flattened sacs stacked on top of each other. This
is one place in the cytoplasm where proteins are made.
Storage site and may also modify proteins after being made in ER
Controls all activities of the cell and contains all genetic information
(chromosomes). It is surround by a nuclear membrane, which allows
chemicals in and out. There is also a nucleolus inside the nucleus.
Animal cells come in all shapes, the cells that cover the surface of living things are thin and flat. Muscle
cells are long and thin, nerve cells that carry info are much longer and thinner than muscle cells. Red
blood cells are disc shaped, while sperm cells have a tail to help them move.
Plant Cells
All animal cells are found in plant cells but plant cells contain a number of other parts. Around the outside
of the cell membrane is the cell wall made of cellulose. This box-like structure is tough but slightly
elastic. The many box-like cells of a plant give it strength and when the plant cell dies, the cell wall will
remain. The vacuoles in a plant cell are very large. In some plant cells it forces the nucleus to the side
next to one of the cell walls. In other plant cells the nucleus may be in the centre of the large vacuole and
be connected with thin strands of cytoplasm to the outside. The vacuoles contain water, salts, sugars and
many other chemicals. Plant cells also come in different shapes, those on the surface are thin and flat.
Cells in the centre of leaves are more box-shaped. There are many long hollow tube-shaped that are used
to carry liquids about the plant. Many cells contain small green bodies called chloroplasts. Chloroplasts
contain the green pigment chlorophyll. This is where photosynthesis takes place. A normal leaf cell may
contain about 40 chloroplasts
Figure.
Most living things contain a very large number of cells. These cells are grouped together so that those
with similar jobs form tissues. Thus the cells of muscles are similar and are grouped o form muscle tissue.
Tissues are grouped together to form organs. An organ is a structure of many tissues that work together to
do a special job. The bodies of more complex plants and animals are made of many different organs. The
four main tissues found in animals are surface (epithelial), connective, muscular and nervous. The
epithelial tissues are lining tissues that cover the surface of an organ. Connective tissues bind tissues such
as cartilage, blood is also classified as connective tissue. Muscular tissues are made of cells, which are
able to contract. There are three types. Skeletal muscle tissues are in the normal muscles that connect to
bones and so move the different parts of our bodies. Smooth muscle lines are blood vessels and digestive
system. Cardiac muscle is made of special tissue and is found in the heart. Organs and tissues working
together make up systems. Two systems, the nervous system and the endocrine system control this
coordination.
Cell Division
Mitosis - Is the division of one cell into 2 identical halves. The number of chromosomes in the two new
cells is the same and equal to the parent cell. This is know and asexual reproduction. It is used by
organism to replace dead cells to repair damaged cells and for growth and development of the organism.
The new cells are called daughter cells.
Meiosis - This process is also known as sexual reproduction. It produces sex cells or gametes in other
words sperm and ova. The new daughter cells contain only 23 chromosomes.
If there is a slight alteration in a person’s DNA, it will result in non-infectious disease. For example, 95%
of cases of Down syndrome occur when an individual inherits 3 rather than 2 copies of chromosome 21.
Other diseases include Patau syndrome (extra copy of chromosome 18) and metafemales (XXX).
Diseases and Microbes
A disease is a condition where part of all of an organism’s normal physiology function is upset. The four
causes of disease are
Exposure to toxic substances, dioxin-related products and metabolic poisons interfere with the normal
metabolism of body system.
Bad lifestyle that includes insufficient exercise, high stress levels and irregular eating can result in body
system malfunctioning.
High radiation such as ultraviolet light or gamma rays damaging DNA and may cause cancer.
Attack by micro-organisms that seek to exploit the rich food resources of our bodies and makes us sick.
Pathogens can enter our bodies through the respiratory tract, gastrointestinal tract, urinogenital openings
and breaking the skin surface. The modes of transmission they uses are contact transmission (droplet
transmission, direct contact, indirect contact), vehicle transmission (air, water, blood) and animal vectors.
An infectious disease is caused by an infecting organism, which could be microscopic or macroscopic.
The organisms that cause the disease are called pathogens. They can be either viruses (AIDS, measles,
chicken pox) or bacteria (flu, TB, Food poisoning), fungi (tinea, ringworm) or parasites (malaria, typhus,
dysentery).
Non-infectious disease develops as a result of genetic inheritance, nutritional deficiencies, environmental
factors and physiological malfunction. (Down Syndrome, skin cancer, scurvy)
Viruses
Viruses cannot be classified as cells because they do not have any cell structures like cytoplasm, cell
membrane or even a nucleus. They are coated with protein that holds genetic material. The protein’s coat
(caspid) determines the shape. Viruses cannot do any living things except replicate themselves. They vary
in size from 1/100 000 mm to 1/2000 mm.
Bacteria
Tiny, single-celled organisms that are very simple with few structures. Some are harmful while others are
helpful. They have a cell wall and a cell membrane but no nucleus. The membrane surrounds the cell’s
contents including the genetic material. Some bacteria have pili or hairs and others may have a long shiplike structure called a flagellum. They live as single cells, in groups or chains or clusters. The size of
bacteria varies from 1/10000 mm to 1/20 mm. Diseases that are caused are TB, flu, food poisoning or
tetanus. Bacteria reproduce by binary fission where they simply divide into two identical cells.
Protozoa
These are single-celled organisms that have a variety of shapes. They have cell membranes that surround
the cell contents or cytoplasm .The genetic material in these organisms is contained in a nucleus.
Amoebae move by using foot-like projections called pseudopodia. As the amoeba extends the membrane,
the cytoplasm oozes in allowing it to move. The cell is always changing shape. The paramecium uses tiny
hair-like structures called cilia to move around. The euglena uses a flagellum to move. They vary in size
from ½ mm to 2 mm. They reproduce by binary fission. The cause diseases such as amoebic dysentry,
malaria
Fungi
Most fungi are multicellular. Fungi absorb nutrients from their surrounding by feeding upon dead
organisms. They vary in size from 1/20 mm to 50 cm. Some of the microscopic fungi cause diseases like
thrush, ringworm and athlete’s foot.
The Watson-Crick Model of DNA
DNA (deoxyribonucleic acid) is a long, continuous, ribbon-like chemical that is wound around groups of
protein beads (histone) to form a structure called a nucleosome. The nucleosomes are coiled around each
other to form a thread, which in turn is coiled up to form a chromosome. Chromosomes exist as
homologous pairs along each chromosome are genes. A gene is one section of DNA on a chromosome
responsible for one trait. Through mitosis, chromosomes replicate themselves exactly. Therefore DNA is
replicated as well. Mitotic cell division continues from the embryo stage (8 weeks), foetus, baby, child,
adolescent and an adult. In this way growth from a single cell zygote to an organism made up of many
cells, each with identical DNA.
Genetic Mutation
Mutation is the change in the genetic material of an organism. It can either be gene mutation (small
change in 1 or more base pairs in the actual DNA) or chromosome mutation (change where chromosomes
are broken, lost or rearranged). Mutation can be beneficial as it provides variation in a species. Without
variation evolution cannot take place. Mutation sometimes provides an advantage for survival such as
more hair (warmth). This usually occurs with gene mutation. On the other hand, gene mutations can cause
genetic diseases (down syndrome) and impede survival causing the individual to die and the mutation to
be prevented from passing on. This usually occurs with chromosome mutation.
Genes are important to cells that they have a backup copy of each gene. That is why chromosomes occur
in pairs. For each gene that occurs on a chromosome, another copy of that gene occurs in exactly the same
position on the other chromosome of the pair. It can be either the same copy or a different copy in either
case a form of a gene is called an allele (Mendel’s factors). Mendel discovered that one variety of a gene
may dominate the other
variety when both varieties are present in the one individual. Mendel’s experiment with pea plants proved
the existence of dominant and recessive genes.
Phenotype of an individual describes any observable traits of an individual, eg. Deep dimples.
Genotype of an individual describes the variety of genes an individual has, for example DD.
Pure breeding occurs when an individual has the same two types of variables of a gene such as AA or aa.
If they mated with another individual with the identical genotype the offspring would have the same
genotype as the parents.
When an individual has different variables for the same gene, such as Aa, they are called crossbreeds or
hybrids for that gene.
Scientist identify dominant genes with capital letters and recessive with smaller case. They also find the
combinations of genes and the probability using punnet squares.
Eg.
Tt
X
Tt
Parents
T
t
T
t
Gametes
X
T
t
T
TT
Tt
t
Tt
tt
Pedigrees
A pedigree is a diagram, which represents the relationship between members in a family group. They are
used by scientists to study genetic traits, to diagnose genetic disease, to make predictions about genetic
disease or abnormality.
Symbols are used in a pedigree.
Sex Determination in Humans
In humans, gender is determined by a pair of sex chromosomes, X and Y. Certain inherited defects which
are much more common in men than in women. These conditions are said to be sex-linked. Among them
are red-green colour blindness and haemophilia. They are caused by recessive genes carried on the Xchromosome. Since the y-chromosomes are shorter than the X-chromosomes they do not carry as many
genes. Among their ‘missing’ genes are those which could influence the sex-linked characteristics. It is
more likely for a woman to be heterozygous for the trait or a carrier. A male cannot be a carrier, if he has
the defective gene, he must show the defective phenotype.
Environmental Factors
One factor that can produce the variable phenotypic effects of genes is the environment. Identical twins
are ideal subjects to use in studies to show the effect of the environment on phenotype. Identical twins
have identical genes but quite often the twins can easily be told apart. Geneticists have hypothesised that
the environment can cause these differences. An example of the effects of the environment is showing in
fingerprints of identical twins. As they start life as foetuses, identical twins have identical fingerprints.
However, at birth the twins have small differences in their fingerprints. In the womb there can be a huge
range of microenvironments. One twin’s fingertips may be constantly rubbing against the skin of the other
twin. The other twin may be a finger sucker. These small changes in the fingers’ environments can
change their prints.
The Theory of Evolution and Natural Selection
Evolution is the gradual change in living things over time in response to environmental changes. This
change is generally from simple to complex. Darwin (Origin of Species) and Wallace accepted that all
living things were descended with modifications from common ancestors, that the large number of
observations he had made were adequately explained by evolution, and that evolution could explained on
the basis of natural selection. The mechanism of evolution is:
1) Variation is characteristic of all plants and animals. Only inherited variation is relevant to evolution.
2) More of each kind of organism is produced than can survive to maturity.
3) Only the fittest will survive.
This is the concept of natural selection. The surviving individuals will give rise to the next generation and
in this way the characteristics of the successful ‘variations’ are passed to the next generation. As time
goes on, large numbers of small changes add up and the population becomes more and more different
from its ancestors. Other populations, descended from the same stock, may evolve in quite different ways
if they are isolated in a different environment. Eventually, related organisms become so unlike that, they
can no longer breed successfully together and now evolved into separate species. Once a species has
become well adapted its evolution may slow down. If its environment then changes, this may lead to the
selection of new adaptations to cope with the changes.
Evidence for Evolution
 The Fossil Record. When fossils are arranged in the order of their age, a continual series of change is
seen, new changes being added at each stage. There are also transitional fossils that show links
between groups that are now separate.
 The Evolution of Horses. There are clear records of horse evolution and this is particularly well
documented and instructive.
 Actual studies of natural selection eg. Peppered moths, Galapagas finches, antibiotic resistant bacteria
(artificial selection).
 The Anatomical Record. When anatomical features of living animals are examined, evidence of
shared ancestry is often apparent. Embryology also shows the similarities in early stages of growth
indicating some sort of common ancestor.
 The Molecular Record. When gene or protein sequences from organisms are arranged, species
thought to be closely related based on fossil evidence are seen to be more similar than species thought
to be distantly related.
 Convergent and Divergent Evolution. Evolution favours similar forms under similar circumstances.
Humans
Humans have multiple systems which work together to sustain normal living. Metabolism refers to all the
chemical reactions that take place in your body, providing energy and allowing growth and repair. Two
systems control the working together of all the systems:
1. The nervous system connects every part of the body to the brain by nerve fibres. A nerve is a thin,
white cord-like structure that consists of neurones. The neurone consists of a cell body from which
long, thin strands reach out. One is usually longer than the others and is the axon, it conducts
impulses away from the cell. The shorter strands are called dendrites and accept signals from other
neurones, carrying them towards the cell body. Myelin surrounds the neurone and stops impulses
jumping from one to another and conducts impulses better. Loss of myelin = Multiple schlerosis.
Signals that allow the body to respond quickly to changes around it are sent and received along these
nerves. In this way, the body is controlled by the brain. The nervous system can be divided into two
main parts:
 The central nervous system is the control centre for the whole body and consists of the brain and
spinal cord. They are both covered by a number of protective membranes called the meninges.
Between two of these membranes is a layer of fluid that helps cushion the brain. Outside these
membranes is a layer of protective bone. The brain contains two types of tissue, white matter (white
myelin-covered axons) connecting the many different areas of the brain and spinal cord and grey
matter (nerve cell bodies, dendrites and special cells that support and nourish the nerve cells).
 The peripheral nervous system consists of nerves that connect the central nervous system with the
rest of the body. These can be cranial nerves, spinal nerves, sensory neurones (to) or motor neurones
(away). There are two main groups of motor neurones:
 Somatic nervous system that controls all muscles that you move at will.
 Autonomic nervous system controls involuntary movement. This can be divided into two parts they
sympathetic system (extreme activity/run away) and the parasympathetic system (conserve
energy).
2. The endocrine system sends its messages more slowly by producing hormones that travel around the
body in the bloodstream. Hormones control the slower changes in the body, such as growth and
reproduction. A part of the brain called the hypothalamus controls the endocrine system.
Vestibular system helps you keep your balance so that you do not fall over. It is located in the ear.
Excretory system gets rid of wastes such as carbon dioxide, urea and some mineral salts. It includes the
lungs, skin and kidneys. The kidneys filter out the blood with nephrons. Each kidney drains into a tube
called the ureter that connects to the muscular bladder and the to the urethra.
Digestive system breaks down the chemicals in our food. Then the chemicals will be small enough to
pass from the digestive system into the bloodstream. The digestive system consists of the mouth,
oesophagus (peristalsis), stomach, small and large intestine.
Circulatory system is the transport system of the body. Many chemicals are carried by the blood The
blood contains red blood cells, white blood cells and platelets. This system consists of all the arteries,
capillaries, veins and the heart.
Respiratory system carries oxygen from the air to the bloodstream; it also removes carbon dioxide from
the blood. It starts from the nose through the trachea and the lungs (alveoli).
Skeletal system supports the body, protects the vital organs and allows a person to move. It also contains
bone marrow, which produces all the new red blood cells and some white blood cells and stores minerals,
especially calcium. The system consists of about 206 bones. Bones can take one of two forms, compact
bone or spongy bone (usually both). The types of bones can be short, irregular, long, sesamoid and flat.
Muscular system enables movement, postural functions enabling us to stabilise the body in various
positions and to generate heat. Muscles make up 40% of your body weight and there are over 630. There
are three different types of muscle tissue, skeletal, cardiac and smooth.
Immune System
The first line of defence is the skin, respiratory system and urogenital system. This includes the sweat,
saliva, urine, hairs and sneezing. The second line of defence is a process called phagocytosis. Phagocytes
seek and destroy pathogens. The next stage is isolation of the area where the pathogen is established so
that it cannot escape and infect other areas. This causes inflammation. Blood vessels increase in size so
that more phagocytes can enter the area. The hypothalamus turns up the heat in the infected area. A type
of white blood cell called lymphocytes recognises pathogens and signals other white blood cells to
remove it. The third line of defence is the manufacture of chemicals called antibodies that bind to the
surface of the pathogen’s cell walls. Once the cell walls are covered in antibodies the cells of the
pathogen cannot function and will die. Every pathogen has a unique surface (antigen) on its walls so our
body has to manufacture a new antibody for each different species of pathogen. Before your body can do
this it has to work out what shape of antibody to build. This takes time and so you become sick. When
your body has developed an antibody it memorises the recipe so that if the same pathogen gets inside your
body again the antibody can be made quickly. Lymphocytes produce antibodies quickly to destroy the
pathogen before it causes a disease. Therefore you have become immune to the disease.
Resistance to a certain disease is called immunity. There are two kinds of immunity, natural immunity
and acquired immunity. Natural immunity is that which you are born with. Acquired immunity is when
you get or develop during your life. The ways you acquire immunity are getting a shot of antibodies for a
certain disease, babies getting antibodies from their mothers, already having the disease and getting a
vaccine. A vaccine is made up of specific dead or weakened disease-causing microbes. When injected it
triggers the body to study the disease and release antibodies. However, you will not get sick, as the
disease is mild.
Cancer
This is a group of diseases that result from uncontrolled cell division. When genes are damaged or altered
they can cause cancer and are called oncogenes. The damage can be caused by radiation, viruses or
chemicals. Cancer-causing chemicals are called carcinogens.
Tumours are a growth of damaged cell division getting out of control. The two types are:
Benign tumours-do not spread to other tissue. They are not normally fatal unless they grow in a vital
organ.
Malignant tumours-grow into surrounding tissue and can be fatal if growth is not stopped. They can
split off and spread throughout the body causing secondary cancers.
Things that increase the chances of contracting cancer are risk factors. They include sunlight, smoking,
alcohol, poor diet, asbestos, chemicals, radiation and gender and age. Warning signs of cancer are:
Bad persistent cough or hoarseness
Change in bowel habits or bleeding from anus
Sore that does not heal
Mole or wart that changes
Unusual bleeding or discharge
Lump in breast, neck, armpit or testicles
Unexplained weight loss
Indigestion or difficulty in swallowing
Reproductive system
The Graafian follicle is a follicle that is connected to the ovary and the fallopian tube it holds the egg until
it is fully matured and then releases it into the fallopian tube. During ovulation an egg is released into the
fallopian tube leaving behind a corpus luteum. This is a group of cells, which form a yellow structure
about the size of a pea, and produces hormones that ensure the walls of the womb continue to thicken in
case a fertilised egg arrives. When a girl reaches puberty there is approx. 500 000 eggs in each ovary.
Each month a single ovum ripens in a follicle in the ovary and is released. 
The two hormones that occur in women are oestrogen and progesterone. In the male it is testosterone.
In the female reproductive system the organs do the following things:
Organ
Function
Kidneys
Filter the blood
Ureter
Transport urine to bladder
Fallopian
Capture eggs and move them to uterus via
cilia. Fertilisation takes place here.
Oviduct
Captures egg
Muscle wall uterus
Through contractions conceive
Bladder
Store urine
Urethra
Passes urine out
Uterus
Develops and holds baby till pregnancy
Ovary
Stores eggs
Cervix
Opening of the uterus ensues baby in
Vagina
Muscular Wall
In the male system
Organ
Vas Deferens
Cowper’s Gland
Spongy tissue
Testicles
Epididymis
Prostate
Scrotum
Seminal Vessel
Function
Carries sperm
Secretes fluids
Fills with blood to make penis erect
Produces sperm
Storage area for sperm
Releases fluid mixes with sperm to make
semen
Sac of abdominal wall. Helps regulate temp.
Release a pale yellow fluid which contains
nutrients
The Big Bang Theory
This theory states that all matter in the universe was originally concentrated into a really small volume
and some 10-25 billion years ago a huge explosion ripped apart this matter and it has been moving apart
ever since. There are three possible outcomes: 1) this expansion will continue forever though it may slow
down somewhat 2) The expansion will slow down and eventually stop. 3) Not only would it slow and
stop it will reverse direction and come back together.
Evidence for Big Bang
First of all, we are reasonably certain that the universe had a beginning. Second, galaxies appear to be
moving away from us at speeds proportional to their distance. This is called "Hubble's Law," named after
Edwin Hubble (1889-1953) who discovered this phenomenon in 1929. This observation supports the
expansion of the universe and suggests that the universe was once compacted. Third, if the universe was
initially very, very hot as the Big Bang suggests, we should be able to find some remnant of this heat. In
1965, Radioastronomers Arno Penzias and Robert Wilson discovered a 2.725 degree Kelvin (-454.765
degree Fahrenheit, -270.425 degree Celsius) Cosmic Microwave Background radiation (CMB) which
pervades the observable universe. This is thought to be the remnant which scientists were looking for.
Penzias and Wilson shared in the 1978 Nobel Prize for Physics for their discovery. Finally, the abundance
of the "light elements" Hydrogen and Helium found in the observable universe are thought to support the
Big Bang model of origins.
Doppler Effect
This is usually associated with an increase or decrease in sound as an object moves closer to you or
further away. It is the wavelengths of sound that are produced by the object that are affect by the motion
of the object. A similar phenomenon occurs with light emitted by stars. By measuring changes in
wavelength, astronomers can calculate a star’s speed and motion, away or towards the Earth. Motions
towards shorten wavelengths shifting the lines towards the blue end of the spectrum. Motion away
stretches the wavelengths and towards the red end of the spectrum.
Hubble’s Constant
The rate at which the universe is expanding. It is calculated 95 000km/s. The concept is related to
Hubble’s Law which says a galaxy’s speed of expansion depends on its distance.
Unit
Value
Astronomical Unit
1.5 X 10^8
Light Year
9.5 X 10^12
Parsec
3.1 X 10^13
Telescopes
Optical telescopes collect light from a celestial body, bring the light into focus and produce a magnified
image. The radio telescope collects radio waves from active objects in space. Some space observations
are impossible from Earth because our atmosphere blocks out some electromagnetic radiations, Radiation
from red dwarfs and exploding galaxies is blocked as well as x-rays and gamma rays from the sun and
infra-red rays from cool objects like comets and nubalae. Images obtained on Earth are also imperfect as
atmospheric currents and dust in the air make stars twinkle and the lighting of cities interferes. Parallax is
also a problem for identifying a celestial’s true position. The distance between the Earth and other objects
are so far away there is a time lag.
The Theory of Plate Tectonics
The theory of plate tectonics--formulated by Alfred Wegener --attributes earthquakes, volcanoes, the
mountain-building process, and related geophysical phenomena to movement and interaction of the rigid
plates forming the earth's crust.
According to the theory, the earth's surface layer, or lithosphere, consists of seven large and 18 smaller
plates that move and interact in various ways. Along their boundaries, they converge, diverge, and slip
past one another, creating the earth's seismic and volcanic activities.
These plates lie atop a layer of partly molten rock called the asthenosphere. The plates can carry both
continents and oceans, or exclusively one or the other. The Pacific Plate, for example, is entirely oceanic.
Convection currents
This hypothesis suggests that convection currents, which drag and move the lithospheric plates above the
asthenosphere, induce flow in the mantle. Convection currents rise and spread below divergent plate
boundaries and converge and descend along convergent. Three sources of heat produce the convection
currents:
(1) Cooling of the Earth's core
(2) Radioactivity within the mantle and crust
(3) Cooling of the mantle
The hot rock closer to the core rises, and the cooler rock further away sinks, as an endless cycle
(convection). This rotation causes movement in the plates. Magma rises through the crust at mid-ocean
ridges, hardens, and forms new crust on either side of the ridge. The old crust is pushed into deep ocean
valleys. This process is called sea-floor spreading, and it supports plate tectonics.
Evidence for Tetonic Plates
• The continents look as if they were pieces of a giant jigsaw puzzle that could fit together to make one
giant super-continent. The bulge of Africa fits the shape of the coast of North America while Brazil
fits along the coast of Africa beneath the bulge.
• Wegener noted that plant fossils of late Paleozoic age found on several different continents were quite
similar. This suggests that they evolved together on a single large landmass. He was intrigued by the
occurrences of plant and animal fossils found on the matching coastlines of South America and
Africa, which are now widely separated by the Atlantic Ocean. He reasoned that it was physically
impossible for most of these organisms to have travelled or have been transported across the vast
ocean. To him, the presence of identical fossil species along the coastal parts of Africa and South
America was the most compelling evidence that the two continents were once joined.
• Broad belts of rocks in Africa and South America are the same type. These broad belts then match
when the end of the continents are joined.
• Wegener was aware that a continental ice sheet covered parts of South America, southern Africa,
India, and southern Australia about 300 million years ago. Glacial striations on rocks show that
glaciers moved from Africa toward the Atlantic Ocean and from the Atlantic Ocean onto South
America. Such glaciation is most likely if the Atlantic Ocean were missing and the continents joined.
• The present northern continents were at the equator at 300 million years ago. The discovery of fossils
of tropical plants (in the form of coal deposits) in Antarctica led to the conclusion that this frozen land
previously must have been situated closer to the equator, in a more temperate climate where lush,
swampy vegetation could grow.
Components of the Universe
Steady State Theory
This theory put forward in 1940s by Hoyle, Bondi and Goid argues that the appearance of the universe is
much the same as it has always been there is no beginning and no end. Galaxies die but are replaced. It
was discredited by observations that objects appear to move away from each other and the average
density of the universe is decreasing. Hence the universe is expanding and not stationary.
Astrometry
Astrometry is positional astronomy, the branch of astronomy concerned with the careful measurement of
position and changes of position of a star or other celestial object to a high order of accuracy. These
apparent position changes can be due to the real motion of the body or the motion of the Earth around its
orbit representing a shifting point of observation. The later case is of particular interest because it allows
movement of distance and the technique involved is the focus of this section.
Brightness of Stars
The brightness of stars is measure by two different scales
Apparent magnitude- measure of brightness of a star as seen from Earth
Absolute magnitude- measure of an object’s real brightness
The smaller or more negative the absolute magnitude the brighter. Apparent magnitude also works on a
scale where low numbers indicates that a star is bright.
Nuclear Fusion in the Sun
When two protons collide one changes into a neutron and releases a positron and a neutrino.
2)
3)
Overall Process
The sun is comprised of 80% hydrogen, 19% helium and 1% heavier elements. The size of our sun creates
huge gravitational forces, which squeeze atoms together creating immense pressure and heat. These
conditions cause the electrons to be striped from atoms leaving positively charged nuclei with rapid
constant motion to undergo the process of nuclear fusion. As the temperatures present in the sun all
materials exist as superheated gasses in the 4th state of matter called plasma.
Nubulae-Clouds of dust and gas are called nebulae.
Novae and Supernova-When a star shines hundred to tens of thousands times brighter than normal it is
known as nova. This happens when huge explosions are shearing an outer layer off the star. Hot gases are
blown outwards. Supernova the explosions are much greater and the star is torn apart
Quasars and black holes-quasars are the glaring centres of remote and turbulent galaxies. The brilliant
light is thought to come from a disc of gas spiralling under intense gravity into a black hole.
Pulsars-a pulsar or neutron star emits extremely regular pulses of radio waves. Some also give off short
bursts of visible light, x-rays and gamma rays.
Gaseous cloud of hydrogen and sooty dust
Yellow main-sequence star forms
Yellow star shines for
10 billion years
Star’s shell expands and cools down
Protostar glows dull red
hydrogen burns in core
core starts to shrink
Red giant forms as helium fuses to form carbon in the core
Bright outer layers ejected
Planetary nebula forms
White dwarf forms
Cools for a billion years
black dwarf forms
Large, hot blue-white stars burn
their fuel for 1 million years
Very large hot blue stars
Swell to form red supergiants
Very large red supergiant star
Supernova shines brilliantly
and briefly
Supernova
Pulsar or neutron star forms
Black Hole
Natural Events
The law of superposition states that the oldest rock is the layer on the bottom. The law of cross-cutting
relationships states that igneous rocks that intrude other rocks are younger than the rocks they intrude.
Fossils
Fossils are traces or remains of organisms that have been preserved. Only certain rocks care suitable for
preserving fossils. Igneous or metamorphic rocks will not contain fossils. Similarly, rocks with a very
coarse structure, such as conglomerates, will usually destroy the remains of any organism before they can
be fossilised. The best types of rock for preserving fossils are limestones or such fine-grained sedimentary
rocks as shales and mudstones. Certain conditions must also be present at the time the animal dies.
Oxygen must be excluded so that decay is slowed. If the organism is covered with sediment it and is not
destroyed by scavengers or the weather it stands a much better chance of being preserved. Marine animals
have a better chance of being preserved, those on land generally need to be swept into lakes, rivers
swamps or peat bogs to be preserved. Fossils can also be preserved in sand dunes, volcanic ash and ice.
Direct evidence is soft parts, hard parts, carbonisation, replacement, permineralization or petrifaction and
recrystallization. Indirect evidence is preservation as molds and casts, tracks and trails, burrows and
borings and coprolites.
• Petrification: the process in which the porous structure of organic material such as bones, shell, and
wood is infiltrated by salt-bearing groundwater, which preserves the structure when it solidifies.
• Carbonisation: the burning, fossilisation, or chemical treatment of something that turns it into carbon.
• Recrystallization: Change of the internal physical structure of some shells so the original
microstructure is blurred or lost and shell is converted into a mosaic of interlocking crystals.
Commonly maintains the original composition but sometimes changes one mineral to another of
similar chemical composition. Eg. Argonite to calcite.
• Replacement: Involves the complete removal of the original hard structure by solutions and the
deposition of new mineral substances. Replacing minerals usually calcium carbonite, silica and pyrite.
• Trace Fossils: a feature in sedimentary rocks that resulted from the activity of an animal, for example
a worm cast or footprint.
• Casts: preserved sediment made by the infilling of an impression such as a footprint
• Types of Fossils: they can be animals, plants, footsteps, burrows, nests, eggs, faeces etc.
The history of an area can be determined from rock layers and the fossils they contain. When rock layers
form containing these fossils, we can infer what the area was like at that time. Eg. A rock containing
fossil footprints was on land when it formed and a rock containing fish bones must have been under
water.
Movement of Rocks
Movement in rocks fit into two groups: folds and faults.
Folds are caused by gradual movements of the rocks under great pressure.
1.
2.
Over fold
Monocline
3.
4. Anticline
Syncline
Sudden movements such as earthquakes can cause breaks in rocks called faults. Depending on the way
the rocks move, they are called normal faults, reverse faults or strike-slip faults (transform).
Normal
Reverse
Plate Movement
There are four ways in which the edges of the plates move compared to each other: sliding, subduction,
collision and spreading.
1. Sliding edge occurs when the two plates are moving in the same direction, but at different speeds eg.
San Andreas Fault. Sections of this fault system are sliding smoothly, other sections build stress
because of a blockage. When this stress becomes too high, they jolt and move suddenly (earthquake).
2. Subduction occurs where one plate goes under another. This could be one oceanic crust going under
another eg. Japan. It also occurs where oceanic crust runs into continental crust eg. Coast of South
America. The continent cannot go under because it is lower density and so must float on the surface.
3. Collision zones are where two continents collide, neither will go under because their density is too
low so instead they produce huge mountain chains.
4. Spreading zones are where two plates move away from each other. New oceanic crust is being
produced at these points. This activity causes ridges, known as mid-ocean ridges, to form in the ocean
floor.
Collide = convergent
Divergent = separate
Transform = sliding
Geology
Sedimentary Rocks
Sedimentary rocks are formed by the process of weathering erosion, transportation of the sediments,
deposition in lakes or in oceans, pressure and uplift. All sedimentary rocks are classified according to the
particle sizes in the layers. They can also be classified into three main groups 1) Clastic-formed from
older rocks and minerals 2) chemical- these are formed by chemical processes 3) organic rocks-these are
formed by biological processes.
Sedimentary rocks are formed in marine areas, transitional areas (shore lines) and continental areas.
A distinctive feature of rocks is the presence of larger or bedding. The scale used to determine the size of
sediments is called the Wentworth Valden scale.
The vast majority of sedimentary rocks have their sediments transported by water.
Conglomerate-high energy environment, fast flowing water, typically formed in upper reaches or rivers or
mountainous areas or during floods.
Sandstone-medium energy environment, rivers or near shore.
Shale-low energy in quiet waters such as lakes, lagoons
Limestone- a low energy environment typically formed in shallow seas in warm climate. This variety is
inorganic meaning mineral based. Coral reefs and deep-sea basins are organic.
Igneous Rocks
Solidified from molten material either under (magma) or on top of (lava) the Earth’s surface. They are
known as plutonic (intrusive) or volcanic (extrusive) igneous rocks respectively, because plutonic rocks
cool and solidify slower than volcanic rocks they have larger crystals.
Plutonic – granite, dolerite. Volcanic – basalt, rhyolite, obsidian, pumice
Metamorphic Rocks
Formed when other rocks are changed. Rocks can be changed by intense heat inside the crust or by the
huge pressures that accompany Earth movements. The particles or crystals are either melted and
recrystallised or crushed into other shapes or both. Eg. Slate/shale, schist/slate, quartzite/sandstone,
marble/limestone, gneiss/granite
Natural Disasters
Disaster
What are they?
Cause
Damage
Tsunamis A series of waves of extremely long
Earthquakes that
Damages
wavelength and period generated in a occur on the sea
lithosphere,
body of water by an impulsive (750) floor usually cause unpredictable,
disturbance that displaces the water.
tsunamis.
undetectable
Cyclones Spiralling wind that may reach up to Tropical cyclones
Destruction,
300 kph as they move around a
develop over
flooding
central region called the eye.
oceans temp. >25 C
Volcanoes
A volcano forms when a crack in the crust extends through to the molten rock underneath. Volcanoes are
classified according to the shape of the cone:
Shield volcanoes, have a large wide base and a low profile. They form from quiet eruptions, which
involve large quantities of thick, runny lava gushing out of the crater, and over the sides.
Cinder cones form from explosive volcanoes that throw their molten material into the air where it cools
and falls back to earth as cinders. A cinder cone is much more steeper and smaller at the base because it is
composed of accumulated cinder.
Composite cones form when volcanoes alternately erupt with lava flows and explode with cinder fallout.
Volcanoes are classified according to whether they are currently active (last 20 years), dormant (for more
than 20 years) or extinct.
Destruction to lithosphere and pollutes atmosphere and hydrosphere.
Earthquakes
Is the shaking of the ground becomes of a sudden movement in the earth’s crust. Earthquakes are
measured in two ways, intensity (Mercalli) and magnitude (Richter). Earthquakes can cause tsunamis and
damage the biosphere, lithosphere and such.
Biotic agents are all the factors that affect an organism through all other living things either directly or
indirectly. These include predators, parasites, disease, competition between members of the same species
and availability of food.
Abiotic factors are all the factors that affect an organism’s ability to survive and reproduce. These factors
are non-living and physical components that affect an organism. These factors include things like light
intensity, temperature range, type of soil or rock in the area, pH level of soil, water availability, gases in
environment, availability of living space and level of pollution.
Importance of Carbon Cycle
Carbon is the building block of life and is present in all living things. It also is needed in the process
photosynthesis in the form of carbon dioxide. Without it oxygen and plants could not survive and life
would not exist.
Importance of Nitrogen Cycle
Nitrogen is essential for many biogical processes. It is included in all amino acids, incorporated into
proteins and is present in the four bases that make up nucleic acids. Nitrogen processing is necessary to
convert gaseous nitrogen into forms useable by living organisms.
Importance of Nitrogen Cycle
Nitrogen is essential for many biogical processes. It is included in all amino acids, incorporated into
proteins and is present in the four bases that make up nucleic acids. Nitrogen processing is necessary to
convert gaseous nitrogen into forms useable by living organisms.
Sustainable Strategies
International Laws and Agreements--Follow up and reoccurrence of conferences like the Kyoto Protocol
Governments working with individuals and providing education to the general public about conserving
the environment with events eg. Clean Up Australia Day, pamphlets, posters etc.
Research into sustainable development sustainable use of resources—Scientists believe that it is possible
to have economic growth while reducing waste at the same time. TO achieve this the idea that we need to
change the way we live needs to be promoted.
Importance of Natural Resources
Natural Energy Resources such as wind, solar, tidal and hydro-electric energy are important economically
as the actual energy comes at no cost at all. The cost comes only within building the stations and their
maintenance. Once this is overcome the energy is free, making the stations a logical and advantageous
economical investment.
Natural resources are also commodities that are considered valuable in their natural form. A resource is
considered natural when the primary activities associated with it are purification and extraction as
opposed to creation. Mining, oil extraction, fishing and forestry are considered natural-resource industries
while farming is not.
Changes in climate have a significant effect on the carbon cycle. Increases in atmospheric carbon dioxide
concentration increase plant photosynthesis and the amount of carbon stored in vegetation. However,
increases in temperature also lead to increases in plant and soil respiration rates, which tend to reduce the
size of the terrestrial carbon store. In some regions, the changes in climate (such as decreased rainfall) can
also reduce plant photosynthesis and reduce the ability of vegetation to remove carbon. Industrialisation
has also contributed additional carbon dioxide to the environment.
Technology
Machines
A machine is a body that makes our work easy or easier. There are simple machines and complex
machines. A complete machine essentially does the same thing as a simple machine but has more than
one simple machine built into it. Engines need a source of energy to drive it. There are three main types of
help:
• Increase in force
• Change of speed
• Change of direction
Levers
First Order Levers - Fulcrum is between load and effort. Effort arm greater than load arm, effort is
increased. If load arm greater than effort arm, movement is increased. It is a force or movement
magnifier.
Second Order Levers - the load is between the fulcrum and the effort. Always magnifies effort. Therefore
it is a force magnifier.
Third Order Levers - Effort between the fulcrum and the load. It always magnifies movement. It is a
movement or speed magnifier.
M.A is a measure of how much a lever magnifies the effort used to do a job. It is:
M.A= Load = Length of the effort arm
Effort
Length of the load arm
1st order levers have a mechanical advantage or disadvantage depending on relative lengths of their lever
arms.
2nd order levers always provide a M.A.
3rd order levers always provide a M.A less than 1. However greater movement offsets this.
Some levers produce more than one mechanical advantage; they produce a “couple” and cannot be
classed.
Wheel and Axle
Axle and wheel consists of a larger wheel connected to a smaller wheel (or shaft) called an axle. When
axle turns, the wheel turns. One complete turn of the shaft produces one complete turn of the wheel. The
wheel does not have to be a complete wheel it can be a handle. If effort is applied to larger diameter
wheel and the load to the smaller diameter axle, then it will increase force. If effort is applied to the
smaller diameter axle and the load to the larger wheel, than increases speed of rotation. Calculate M.A:
M.A= Load = Diameter of Wheel
Effort Diameter of Axle
Gears
Gears are simply wheels with teeth or cogs to prevent them from slipping. Gears are used to make wheels
turn more efficiently than belts of friction due to direct contact. They can also be connected by a chain
belt or can have huge cogs in direct contact. Gears can used to change both direction of applied force and
the speed at which the different wheels turn. The M.A is determined by:
M.A = Load = Radius of the drive wheel
Effort Radius of the driven wheel
Inclined Plane
This is a sloping surface or ramp that connects a lower and a higher surface. It allows the use of less force
to move an object up (or down) to the higher (or lower) level than if it was lifted vertically. Incline planes
are force magnifiers because they can change a weak force acting through a long distance into a strong
force acting through a short distance. The M.A is:
M.A = Load = Length of the inclined plane
Effort Vertical Height of Plane
Wedges
This is a simple machine used to either spread an object apart or raise it. They are simply a single or
double inclined plane but differ from the way they are used. Wedges move into or under but objects
move up or down inclined planes. Wedges change the direction of the force applied as well as increase it.
The longer and thinner the wedge, the greater the gain in force ie. Wedges are a force magnifier. Eg.
Axes, spear points, chisel The M.A is calculated by:
M.A = Load = Length of wedge
Effort Thickness of far end
Screws
A screw provides a gain in force. The smaller the pitch, the greater the gain in force. Pitch is the distance
between 2 spiral of the thread. Thread is the spiral part of the screw. The M.A is:
M.A = Load = Circumference of screw head
Effort
Pitch
Pulleys
A pulley is a wheel that turns a stationary axle. It usually has a groove in the rim to carry a rope. Pulleys
can be used to change the direction of an applied force. A single pulleys changes direction but does not
provide M.A. Pulleys used in combo form a block and tackle. This combination is a force magnifier and
provides a mechanical advantage. This is found by:
M.A = Load = Distance effort moves = Load lifted
Effort Distance effort moves
Effort Applied
Uses of Nuclear Energy
Nuclear energy can be used to create unstable isotopes called radioisotopes. These can:
• Treat Cancer. A high dose of radiation, often from cobalt-60 isotope, directed at cancer cells can kill
them. However, not only does it kill the cancer cells but also it affects any healthy cells it passes
through. Often it doesn’t kill all the cancer cells and the cancer may reappear.
• Chemotherapy makes use of the fact that some parts of the body absorb some elements and others do
not. The thyroid gland absorbs iodine. A person with thyroid cancer could be given an injection
containing a measured dose of radioactive iodine, which would be concentrated in the thyroid and
hopefully kill the cancer cells there. Though while it is flowing through the bloodstream, the isotope
can kill many other cells.
•
•
•
•
•
•
•
Bone scans. Technetium-99 is absorbed by injured bones but not by healthy bones. This injected into
the bloodstream will concentrate at any bone injury and can be detected using a gamma camera.
Radioactive tracers are used to study how plants absorb different chemicals, how water flows through
the ground or how an element behaves in a chemical reaction.
Detecting flaws. Radioisotopes are used inside pipe or on the other side of a metal sheet. Any flaws in
a welded join in a pipe or in the internal structure of a metal sheet itself can be detected if any
radiation appears through the weld or on the other side of the sheet. Stress fractures in aeroplane
wings are detected this way.
Sterilising. Radioactivity kills living cells it can be used to sterilise medical and surgical instruments.
The instruments are sealed in plastic and then exposed, killing bacteria.
Food preservation. Radiation can also be used to kill bacteria that might cause food to ‘go off’. Again,
it is sealed before being exposed.
Production control. The thickness of paper sheeting can be controlled using radioisotopes. Beta
particles can be passed through paper as it is being produced. Variations in thickness are measured by
the amount of radiation passing through the paper to a detector on the other side. The detector can be
connected to an automatic pressure adjuster on the rollers.
Carbon dating. Can measure the age of a dead organism through half-life.
Nuclear waste is a problem for many countries as it takes a long time for the radioactive material to break
down. There are several methods to get rid of waste but they are not fool proof.
Biotechnology
The use of living things, especially microbes, to produce useful products is known as biotechnology.
Hundreds of useful products are produced by genetic engineering. Genetic engineering is a branch of
biotechnology. Genetic engineering is done by using plasmids, which are circular DNA molecules found
in bacteria. Genes from one organism are inserted into the plasmids of a bacterium to create new DNA.
This new DNA is called recombinant DNA. The plasmids are then returned to the bacteria, which then
reproduce, making more copies of the new DNA. This is called cloning. Since the bacteria reproduce so
quickly, many copies of the inserted gene and its products can be quickly produced. A bacterium called
Escherichia coli is often used in genetic engineering, because it is easy to grow and its biochemistry is
well understood. These E. coli are used as chemical factories for making products needed by humans such
as insulin, human growth hormone and proteins for heart attack therapy. Biotechnology can also be used
to increase yields in agriculture, help the environment (breaking down oil and such) and has forensic
applications.
Some implications of biotechnology include:
Escaping, one of the earliest concerns was the manipulation of micro-organisms. Many people feared that
this could create hazardous new microbes that could escape from the laboratory. Guidelines were set up to
ensure safety. Microbes are tested again and again for the affects on humans and the environment.
Parents may soon be able to choose characteristics of their child like sex, height, intelligence, skills, eye
or skin colour. Children could be an exact clone from one of their parent’s genes or a celebrity’s whose
genes their parents paid for with great price. Genetic engineering may cost a lot and this will be another
factor bridging the rich from the poor. The rich can say that their children are better and have the genetic
information to prove it. There will be distinct social classes; those of genetic enhancement and those
weird and normal. This is only with the human species, potentially genetic engineering could breed new
plant and animal diseases and sources of cancers. There is also uncertainty of who is responsible and will
take the decisions of genetic engineering. Religion and belief also prop up, we are now reconstructing
nature and ‘playing god’. There are now organisms which are partly human many questions arise like
“What percent of human genes does an organism have to contain before it is considered human?”.
Vegetables can be injected with human genes to make them grow faster so you can be a vegetarian and a
cannibal at the same time. Another issue are mice that are genetically engineered to produce human
sperm. “How would you feel if your father was a genetically engineered mouse?”
There are dangers with governments manufacturing biological weapons. So that we would not
have to be dependent on petroleum-based plastics, some scientists have genetically engineered plants that
produce plastic within their stem structures. They claim that it biodegrades in about six months. If the
genes escape into the wild, through cross-pollination with wild relatives or by other means, then we face
the prospect of natural areas littered with the plastic spines of decayed leaves. It has the potential for
disrupting entire food-chains. It can be eaten by invertebrates, which are in turn eaten, and so forth. If
primary foods are inedible or poisonous, then whole food-chains can die off. Genetic engineers intend to
profit by patenting genetically engineered seeds. This means that, when a farmer plants genetically
engineered seeds, all the seeds have identical genetic structure. As a result, if a fungus, a virus, or a pest
develops which can attack this particular crop, there could be widespread crop failure.
The greatest threat about genetic engineering is that gene pollution cannot be cleaned up. Once
genetically engineered organisms, bacteria and viruses are released into the environment it is impossible
to contain or recall them. Unlike chemical or nuclear contamination, negative effects are irreversible.
Importance of the Water Cycle
Integral to keeping all living organisms
gives plants and animals water to drink,
us with weather patterns
alive,
provides
to keep our crops growing, basically
all life on earth.
sustains
The Impact of Human activities on the
environment
There are many ways in which humans
impact
the natural state of their environments
through
their activities, directly and indirectly.
We use
our natural surroundings to grow our food supply, a place for recreation, our habitats, and mine it for
natural resources for industrial products. The clearest evidence of human impact can be seen the reduction
and fragmentation of habitats and landscapes and the loss of flora and fauna. The expansion of humans
activities into the natural environment manifested by urbanisation, recreation, industrialisation and
agriculture result in increasing reduction, disappearance, fragmentation or isolation of habitats and
landscapes, therefore inflicting decreasing species numbers due to habitat loss, habitat damage and
pollution from the air and farming.