Download Foundation Worksheet 1

Answers to textbook questions
Chapter 1 Elements and the
periodic table
1.1 SEARCHING FOR ELEMENTS
QUESTIONS
1 Fusion—atoms joining together to form heavier
elements. For example, hydrogen atoms fuse to form
helium.
2 Scientists study the chemical composition of stars by
investigating electromagnetic waves produced by
stars (e.g. visible light, X-rays and microwaves).
3 Copper is the most likely element present. Sodium
gives yellow light and strontium gives red.
4 Carbon dioxide.
5 Products formed are carbon dioxide gas, water and a
metal salt. Hydrochloric acid will produce chloride
salts. Example:
Na2CO3 + 2HCl  CO2 + H2O + 2NaCl
sodium
hydrochloric carbon
water
sodium
carbonate
acid
dioxide
chloride
do not necessarily correspond to the English name
(often it is the Latin name).
2 In period 4 the three elements whose symbols do not
match their name in English are potassium (K), iron
(Fe) and copper (Cu).
3 Element 19 is potassium. Elements with similar
properties are other group I elements: lithium,
sodium, rubidium and cesium.
4 The lightest and smallest element is hydrogen,
symbol H, atomic number 1. The heaviest element
found in nature is uranium, symbol U, atomic
number 92.
1.4 PROPERTIES OF THE ELEMENTS
QUESTIONS
1 Nitrogen, phosphorus (non-metals); arsenic, antimony
(metalloids); bismuth (metal).
2
THINK ABOUT
Elements heavier than uranium are produced artificially
and do not form inside stars. These elements are
produced inside nuclear reactors or machines called
cyclotrons.
1.2 MAKING SENSE OF THE ELEMENTS
QUESTIONS
1 Mendeleev constructed a periodic table by arranging
the elements with similar properties into vertical
groups and increasing atomic mass into horizontal
periods.
2 The modern periodic table has almost double the
original number of elements.
3 Mendeleev realised that there must be more elements
than those identified at the time.
4 They are very stable elements.
THINK ABOUT
1 Student summary of Figure 1.7 will vary.
2 Element 114 will be most like the elements in the
same vertical group (e.g. lead).
1.3 THE PERIODIC TABLE
QUESTIONS
1 The name of each element can be represented by one,
two or three letters of the alphabet. The letter symbols
Heinemann Interactive Science 4
3 86 metals, 17 non-metals, 8 metalloids.
4 a 7
b Lithium, beryllium, boron, carbon, nitrogen,
oxygen, fluorine and neon.
c Si silicon, Cl chlorine, Na sodium, Fe iron,
K potassium.
d Iron (Fe).
THINK ABOUT
The group number of an element is also the number of
electrons found in the outer shell of that element. Choose
any elements from the first 20 to demonstrate this rule.
For example, chlorine is found in group VII. It has an
electron structure of 2,8,7—seven electrons in the outer
shell.
1.5 PATTERNS WITHIN THE PERIODIC
TABLE
QUESTIONS
1 a Reactivity of metals increases down a group.
Answers to textbook questions  1
b Size of atoms increases down a group.
c Ability to hold onto outer electrons decreases
down a group.
d Metallic character of elements increases down a
group.
ACTIVITY
The element is phosphorus. Clues: Found in period 3,
group V. Electron structure is 2,8,5. Next-door neighbour
is silicon.
2
1.7 INSIDE THE NUCLEUS
QUESTIONS
Group II metals are called alkaline earth metals.
3 a 2
b 3
4 a Fluorine (F): electron structure 2,7; 7 outer shell
electrons; 2 shells.
b Chlorine (Cl): electron structure 2,8,7; 7 outer
shell electrons; 3 shells.
c Iodine (I): electron structure 2,8,18,18,7; 7 outer
shell electrons; 5 shells.
1 In theory the train ticket contains 90 thousand million
times its mass in energy, contained in the strong
nuclear forces binding the nucleus together. If this
could be released and harnessed, it would provide
sufficient energy to move the train.
2 E  mc2 gives the energy E obtained if a mass (m) is
completely converted to energy. It is equal to the
square of the speed of light (c) multiplied by the mass
(m).
3 Fission means to split, in this case the splitting of a
nucleus to form two smaller atoms.
4  and  radiation and  rays.
THINK ABOUT
Clothes made from aluminium.
1.6 A JOURNEY ACROSS THE TABLE
1.8 ISOTOPES IN ACTION
QUESTIONS
QUESTIONS
1 Solid (sodium to sulfur); gas (chlorine and argon).
2 Physical size decreases. As the atomic number
increases by 1, the extra proton inside the nucleus
holds the surrounding electrons more strongly.
3 a Group IV, period 2, carbon.
b Group VIII, period 2, neon.
c Group I, period 4, potassium.
d Group V, period 3, phosphorus.
4 a Sodium (Na) is the most reactive; aluminium (Al)
is the least reactive.
b Chlorine is the most reactive; silicon is the least
reactive.
1 An isotope refers to different kinds of atoms of the
same element. Isotopes of the same element have the
same atomic number but different mass numbers, i.e.
different numbers of neutrons in the nucleus.
2 a The atomic number is the number of protons in
the nucleus of an atom.
b The mass number is the number of protons plus
neutrons in the nucleus of an atom.
THINK ABOUT
Moving left to right across a period: metallic character
decreases, metals become less reactive, non-metallic
character increases and non-metals become more
reactive. The journey ends at group VIII with a very nonreactive noble gas.
Heinemann Interactive Science 4
3
Isotope
Number of
protons
Number of
neutrons
Number of
electrons
a
4He
2
2
2
b
12C
6
6
6
c
13C
6
7
6
d
197Au
79
118
79
4 Cobalt-60 is the isotope of cobalt with a mass number
of 60. It has 27 protons and 33 neutrons.
Answers to textbook questions  2
5
Isotope
Atomic
number
Mass number
APPLY YOUR SKILLS
a
Al-27
13
27
b
31
15
31
c
131
53
131
P
I
1
6 Isotopes can be used in nuclear reactors, as tracers, to
sterilise medical equipment and foods, to destroy
cancers, in smoke detectors, in carbon dating
archaeological remains.
1.9 NUCLEAR POWER
QUESTIONS
1 24 000  10  240 000 years
2 The heat generated by the fission reaction is used to
create steam, which drives the turbines, to drive the
generators, to generate electricity.
3 Ukraine, Russia, and western parts of the former
USSR.
2
Isotope
Atomic
number
Number of
neutrons
Number of
electrons
5
6
5
a
11
b
12
6
6
6
c
16
8
8
8
d
24
12
12
12
e
25
12
13
12
f
32
16
16
16
B
C
O
Mg
Mg
S
12
14
C and C have the same atomic number but
different numbers of neutrons. They are different
forms of the same element, called isotopes.
3 63.
4 22Ne indicates a mass number of 22, whereas 10Ne
gives only the atomic number.
5
THINK ABOUT
1 Nuclear waste is radioactive and even small quantities
are extremely dangerous. It is very difficult to dispose
of nuclear waste safely as it remains radioactive for
such a long time.
2 Away from populated areas, on stable ground (not
subject to earthquakes) and away from high water
tables (in case of leakage).
1.10 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
Across 1 hydrogen 2 ge 3 co 7 calcium 8 os
9 uun 10 ti 14 mendelevium 15 re 16 silicon
18 hf 19 lr 20 uranium 23 mo 24 be 28 rubidium
Down 1 helium 2 gd 3 neon 4 sodium 5 ga
7 chlorine 11 sn 12 mercury 13 lithium 16 silver
17 la 21 nd 22 mo 25 sb 26 ni 27 pm
CHECK YOUR KNOWLEDGE
6 a N and P are in the same group because they have
the same number of electrons in the outer shell.
b He, Be, N are in period 2. All have 2 shells of
electrons. Al and P are in period 3. Both have
3 shells of electrons.
CHALLENGE YOURSELF
Nuclear fission requires atomic nuclei to be split, while
nuclear fusion describes a process of joining atomic
nuclei. Fusion reactions can be utilised safely once the
problem of what to do with the byproducts has been
overcome.
Chapter 2 Chemistry of the car
2.1 MATERIALS IN A CAR
QUESTIONS
1 Any five of the following: iron, aluminium, lead,
beryllium, nickel, zinc, molybdenum, tellurium.
2 Petroleum or crude oil is a thick greenish-brown
flammable liquid that is found in porous rock
underground.
Heinemann Interactive Science 4
Answers to textbook questions  3
3 Some reasons for replacing metal components in cars
with ceramics include that they are lighter, stronger
and more heat resistant than steel.
1 Student’s own answer required.
2 A need for cars to use less fuel and be more economic
and less polluting has driven the motor car industry to
build more compact and lighter-weight cars.
3 Injection moulding is used for the manufacture of
lids, caps, toys, mixing bowls. The molten plastic is
injected into a mould of the desired shape and cooled,
then the shape ejected as a ready-made part.
Rotational moulding is used for the manufacture of
boats, canoes. The molten plastic is injected when the
shape is rotated. The plastic covers the inside of the
mould in two different directions while rotating.
4 Rotational moulding could be used to make a plastic
fuel tank as a smooth continuous surface is required.
2.2 CRUDE OIL
2.6 RUSTING WRECKS
QUESTIONS
QUESTIONS
THINK ABOUT
1
2
3
4
5
The ending ‘ane’.
At least one triple bond between carbon (C) atoms.
Ethane, heptene, heptyne, heptane, methane, pentene.
Gas to liquid to solid.
Effect of double bond is to restrict rotational
movement.
1 Corrosion is the weakening or breakdown of metals.
Rusting is a form of corrosion, where oxygen
combines with iron to form iron oxide or rust.
2 A redox reaction occurs in two parts: oxidation, when
atoms lose electrons; and reduction, when atoms gain
electrons.
2.3 PRODUCTS FROM OIL
THINK ABOUT
QUESTIONS
1 Iron oxide is brittle compared to iron so is not
suitable for cars that require strength.
2 Examples: zinc, magnesium.
1 Small (C1–C5).
2 Victoria’s crude oil is high in the light molecules, not
the heavier fractions from which bitumen is made.
3 Any two of fractional distillation, catalytic cracking
or catalytic reforming.
4 Different components of the oil boil (and therefore
condense) at different temperatures. The temperature
decreases up the tower, so the different components
condense at different points up the tower, where they
can be collected.
5 To allow for a greater amount of separation by
condensation of the components of the crude oil.
2.4 PRODUCTS OF PETROCHEMICALS
QUESTIONS
1 Five products composed of any of the following (or a
combination of the following): polyethylene,
polypropylene, PVC, PVA, polystyrene, polyesters
and polyurethanes. These may include milk
containers, combs, brushes, shampoo containers,
toothbrushes, etc.
2 Alkenes.
3 The production of ammonia for fertilisers.
4 Low adhesion or lack of clinging between sheets of
polythene film.
2.7 PREVENTING CORROSION
QUESTIONS
1 Protective coating (e.g. paint), coating with a less
reactive metal, electroplating, layers of grease or oil,
use of alloys, corrosion inhibitors added to water.
2 Some methods of protection are unsuitable for
moving parts as the material used may have a low
melting point or can get worn away easily. Suitable
methods would be to use alloys, layers of grease or
oil.
3 Malleable: metal characteristic where a flat sheet can
be produced. Ductile: metal characteristic where a
wire form can be produced.
4 The use of a metal is based on the physical properties
such as melting point, conductivity, malleability,
ductility, corrosion resistance.
2.5 PLASTICS IN CARS
QUESTIONS
1 Polymers are made from very long chain molecules
called monomers.
2 Polystyrene monomers are styrene. Polyvinyl chloride
monomers are vinyl chlorides.
Heinemann Interactive Science 4
Answers to textbook questions  4
2.8 INSIDE THE ENGINE
increase in the amount of heat being retained by the
atmosphere.
QUESTIONS
THINK ABOUT
1
1 Climatic conditions that have the effect of increasing
evaporation or reducing rainfall would increase the
concentration of water vapour in the atmosphere.
2 Methane increase is probably due to activities such as
coal mining and oil drilling which release trapped
methane, and to methane produced in increasing areas
of rice paddy, landfill (tips) and disturbed peat bogs,
and in the guts of increasing numbers of cattle and
other ruminants.
3 Plants take in carbon dioxide and release oxygen in
the process of photosynthesis. Deforestation increases
the amount of carbon dioxide, a greenhouse gas, in
the atmosphere through burning of forest residue and
because it reduces the number of trees that could
remove carbon dioxide.
4 Advantages of an enhanced greenhouse effect are
possibly indirect non-environmental advantages
attained through advances in industrialisation. Some
countries may have less harsh winters, or benefit from
changed rainfall patterns.
2 4CH3 + 7O2  4CO2 + 6H2O + energy
2C2H6 + 7O2  4CO2 + 6H2O + energy
C3H8 + 5O2  3CO2 + 4H2O + energy
3 34 200 kJ
2.9 UNLEADED PETROL AND YOU
QUESTIONS
1 Replacements for some fossil fuels are required in the
near future as reserves are going to be used up.
2 Fuel lines, connections and tanks.
3 Percentage by volume (% vol.) of the amount of
isooctane (100 octane number) and normal heptane
(0 octane number) in fuel.
4 The fuel is igniting before the spark plug fires.
Affects the ‘timing’ of the engine and produces a poor
performing car.
5 To increase the octane rating of unleaded fuel.
THINK ABOUT
Greater use of motor vehicles leads to an increase in the
emissions from fuels, both leaded and unleaded.
Consequently, lead and benzene are found in high
(sometimes dangerous) concentrations in regions of high
motor vehicle usage.
2.10 CARS, GREENHOUSE AND KYOTO
QUESTIONS
1 Surface temperature stability is achieved through
reflection of some incoming radiation (about 10%),
much is absorbed by carbon dioxide, ozone, water
vapour and other less abundant gases, and some is
transmitted to the Earth’s surface. The Earth also
re-emits radiation. The temperature stability is
achieved through a balance of these gases and
reflection, absorption and transmission.
2 The amount of cloud determines the percentage of
solar radiation that reaches the Earth’s surface.
3 Greenhouse effect describes the Earth’s atmosphere
trapping solar radiation, warming the surface of the
planet. Enhanced greenhouse effect refers to the
Heinemann Interactive Science 4
2.11 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
1 Refining is the process of separating crude oil into its
many components.
Crude oil is a thick black cocktail of different types of
oil and other chemicals.
Derivatives are the products of the refining process.
Olefins and paraffins are alkenes and alkanes
respectively.
Hydrocarbons are chemicals that contain hydrogen
(H) and carbon (C).
Nomenclature is a naming system.
Alkanes are hydrocarbons with single bonds between
the carbon atoms.
Alkenes are hydrocarbons with at least one double
bond between the carbon atoms.
Alkynes are hydrocarbons with at least one triple
bond between the carbon atoms.
Sweet oil is crude oil with a low amount of sulfur.
Sour oil is crude oil with a high amount of sulfur.
Engine knocking is the sound produced when petrol
ignites before the spark plug fires.
Octane rating is a ratio measurement between
isooctane (100 rating) and heptane (0 rating).
Fractional distillation is the separation of the
components of crude oil via boiling points.
Monomers are the basic units used to make a
molecular chain called a polymer.
Polymers are long chains of monomers.
Reactivity is the amount of reaction of a metal with
water or dilute acid.
Redox reaction is the reaction between an oxidant and
a reductant (reduced and oxidised respectively).
Answers to textbook questions  5
Reduction is the loss of oxygen or gain of electrons or
hydrogen.
Oxidation is the gain of oxygen or the loss of
electrons or hydrogen.
CHECK YOUR KNOWLEDGE
APPLY YOUR SKILLS
1 Hydrocarbons can be boiled off from a wash solution.
Iron metal can be separated from the solution by
magnetic attraction; other metals can be separated by
displacement reactions.
2 For the local community’s electricity generation or
gas usage.
CH4 + 2O2  CO2 + 2H2O
3 2CO2 + O2  2CO2
4 Gold and silver are more corrosion resistant, i.e. more
stable elements than iron.
5 Advice can be wide ranging but must reflect the
composition of the different types of plastics products
and how they are made.
6 Roads remove vegetation and increase run-off.
7 A 1980 car would have been designed to run on
leaded petrol. The fuel could be unleaded. Further
evidence may include paint samples, metal samples
and eyewitness reports.
8 The enhanced greenhouse effect could cause the
Earth’s atmosphere to trap solar radiation, causing a
warming of the surface of the planet and resulting in
sea level rises.
CHALLENGE YOURSELF
1 Processes must be chemical in their basis. Burning
the tyres is not an acceptable response.
2
3 Different sectors in the community do not all agree on
the causes and effects of the enhanced greenhouse
effect as the data available is not always conclusive
and the different stakeholders each have a vested
interest in promoting their cause.
Chapter 3 Force and motion II
3.1 FASTER THAN A SPEEDING BULLET!
QUESTIONS
1 Example: speed is a special type of rate; speed is how
fast distance changes with time.
2 b and e measure speed: speed units all have the
pattern ‘distance unit per time unit’.
3 a and d. MKSA units are made up of metres,
kilograms, seconds and amperes only.
THINK ABOUT
1 Examples: miles per hour—speed of a car; kilometres
per second—speed of a rocket; centimetres per
year—human growth (height); metres per minute—
speed of a tortoise.
Heinemann Interactive Science 4
Answers to textbook questions  6
2 Accept any reasonable answers. Metres, kilograms
and seconds are fairly ‘human’-sized units, not too
big, not too small.
3 Convention. Kilometres (miles) and hours are all
units appropriate to normal car journey length.
Measuring a journey in metres would be unwieldy.
3.2 HOW FAST?
QUESTIONS
1 A digitector is a speed-measuring instrument that uses
pressure-detecting cords to time traffic.
2 a 83.3 m/min b 1.4 m/s
3.3 MEASURING SCIENTIFICALLY
QUESTIONS
1 a Systematic errors, random errors.
b Systematic error: using a set of scales that are not
properly ‘zeroed’. (Systematic error is dependent
on the particular instrument used to measure
with.) Random error: parallax error in reading an
analogue dial from one side.
2 a Analogue clock, analogue bathroom scales, metre
ruler.
b Digital stopwatch, digital kitchen scales,VCR
clock.
3 Size of reading error is determined by the smallest
scale division on the measuring instrument.
4 52 kg, within 2.5 kg.
on brakes, jumping up, pushing something sharply,
quickly speeding up after cresting a hill.
2 The picture on the right.
3 The apple’s acceleration is always negative (down).
THINK ABOUT
1 Once the apple is in flight the only force acting on it
(apart from air resistance) is gravity. On the way up
the apple is slowing down (velocity up, acceleration
down). At the top the apple stops moving (velocity
zero, acceleration down). On the way back down it is
speeding up (velocity down, acceleration down). The
only effect the throw has is setting the apple in
motion (giving it a starting velocity).
2 Whenever you change direction, but not speed—like
going around a corner in a car at steady speed.
3.6 MEASURING ACCELERATION
QUESTIONS
1 0.1 s
2 0.2 s
3 At 30 Hz (30 dots per second), 5 dots would take
1
5
or 0.167 s.
30
4 To convert cm/s2 into m/s2 divide by 100.
5 Increase in velocity (i.e. acceleration) of 5 km per
hour every second. (Better units would be km/h/h or
km/s/s.)
THINK ABOUT
3.4 ARE YOU GOING MY WAY? VELOCITY
VERSUS SPEED
QUESTIONS
When motion is only occurring in one direction along a
straight line (i.e. direction is fixed), speed can be used to
calculate acceleration.
1 Speed is how fast. Velocity is how fast and in what
direction.
2 NE  45 T, NW  315 T, SE  135 T.
3.7 GALILEO’S EXPERIMENT
THINK ABOUT
1 Yes.
2 No (should have travelled 27 cm at 24 s, or 48 cm
at 32 s).
1 Towards the beach, away from the beach; or , ; or
any other reasonable answer. Buses can move in any
direction, like cars (e.g. could drive parallel to the
beach), but are like lifts when we think about only
to/from the beach.
2 This is quite complicated, and it is intended to elicit
imaginative responses rather than necessarily rigorous
ones.
3.5 BLAST OFF! ACCELERATION
QUESTIONS
QUESTIONS
THINK ABOUT
1 It is difficult to get the exact same conditions, but it is
the relationship between numbers that is important.
2 Galileo worked out the relationship by repeating the
experiment many times.
3 Ensure that the same ball and material are used for
the slope in each case. Ensure that the ball distance
rolled remains exactly the same and only the slope
changes.
1 Examples: Small—coasting down a slight hill, slowly
standing up, pushing something gently, gradually
speeding up (from an already high speed) to overtake
in a car. Large—coasting down a steep hill, slamming
Heinemann Interactive Science 4
Answers to textbook questions  7
3.8 NEWTON’S LAWS OF MOTION
QUESTIONS
1 a 17 m/s  61.2 km/h b 4.25 m/s2 c 807.5 N
2 637.5 N
F
807 .5
3 a 150 kg b a 

 5.4 m/s2 c 21.5 m/s
150
m
4 a Action—deflation; reaction—propulsion.
b Action—pushing water; reaction—forward
movement.
c Action—force on road; reaction—opposite force
in direction of car’s movement.
d Action—air drawn into propeller and out;
reaction—plane moving forwards.
APPLY YOUR SKILLS
1 a
e
2 a
3 a
4 a
c
0.015 m b 7.2 kg m/s2 c 18.1 m/s d 0.11 m/s2
214 m/s f 8200 m
1.8 m/s2 b 1.1 m/s2 c 0.82 m/s2
1.4 m/s2 b 2.8 m/s c 4 s
1.6 m/s2 b 4.8 N
Yuri (11.2 m, as opposed to Sally 12 m).
CHALLENGE YOURSELF
Individual student responses required.
3.9 INVESTIGATING FORCES
QUESTIONS
1 Examples: friction and air resistance.
2 20 N
20
3
= 444 m/s2
0.045
Chapter 4 Work and energy
4.1 KINETIC ENERGY
QUESTIONS
No answers required.
1 a 0.63 J b 31 J c 138 883.3 J
2 Thermal energy is the total energy of the particles
within a substance. Some of the energy of these
particles is energy of movement or kinetic energy.
Note that temperature is proportional to the average
kinetic energy of the particles within a substance.
3 1.0 kg
4 30 J
5 It takes 1.5 seconds for a person to register the need
to brake and the remaining time for the brakes to
work.
3.11 CHAPTER REVIEW
THINK ABOUT
THINK ABOUT
Advantage—clothes wouldn’t wear out so quickly.
Disadvantage—very easy to fall over.
3.10 BIG SCIENCE—PARTICLE
ACCELERATORS
USING SCIENTIFIC LANGUAGE
1 I can eat chocolate at a rate of 8 squares a minute.
2 Correct as written.
3 Slowing down is accelerating. A number of different
correct sentences are possible, e.g. ‘The runner
stopped getting faster, and slowed down.’
4 The speed of the bike was 10 m/s.
5 Acceleration is the rate of change of velocity over
time.
6 Correct as written.
7 When velocity is constant, acceleration is zero.
CHECK YOUR KNOWLEDGE
Heinemann Interactive Science 4
1 Doubling speed, because it increases kinetic energy
by a factor of 4 (since velocity is squared in the
kinetic energy equation). Doubling the mass only
doubles the kinetic energy.
2 100 times heavier.
3 Approximate speed and time taken for the car to slow
down may be determined from the skid marks.
4.2 POTENTIAL ENERGY
QUESTIONS
a 6.3  102 J b 1.2  102 J
a 18 J b 1.7  104 J
a 1.5  102 J b 1.5  102 J c 9.9 m/s
Any change in the baseline will change the
gravitational potential energy since h will change.
5 Gravitational potential energy 4.3  102 J; kinetic
energy 4.3  102 J; speed 4.0 m/s.
1
2
3
4
Answers to textbook questions  8
4.3 CONSERVATION OF ENERGY AND
ENERGY CONVERTERS
4.8 ENERGY AND SPORT
QUESTIONS
QUESTIONS
1 Energy conservation states that energy is not created
or destroyed; it is transformed to other forms.
Chemical potential energy is transformed into light,
sound and heat in this case.
2 Energy may be transferred from one body to another
or transformed from one type to another. For
example, a train carriage transfers kinetic energy to
another when they are coupled, or a boiling kettle
transforms electrical energy into thermal energy.
3 Student answers will be varied.
4 Student answers will vary, but should change solar
energy  chemical energy  heat energy.
4.4 ENERGY EFFICIENCY
QUESTIONS
1 To reach the same temperature, more energy is
required for a room with more molecules (i.e. same
temperature means same average kinetic energy per
molecule).
2 a 20% b 75%
3 60%
4 2.2  103 J
5 Hydrogen can be a more efficient and less polluting
fuel source (electrical energy produced).
4.5 WORK AND ENERGY
1 1200 J
2 Mechanical energy supplied to the ball in
compressing it is transformed into elastic potential
energy and thermal energy.
3 Impact cushioning—absorption of energy to reduce
stress; comfort; stability; cost; image.
THINK ABOUT
1 7 bounces
2 The coefficient of restitution, e, represents the square
root of the fraction of the dropping height to which
the ball rebounds. It is also the ratio of the speed
immediately after the bounce to the speed
immediately before the bounce.
e
v

u
h2
h1
4.9 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
Across 5 kinetic 7 gravitational 8 energy 9 power
10 work
Down 1 efficiency 2 elastic 3 thermal 4 converter
6 transfer
CHECK YOUR KNOWLEDGE
QUESTIONS
1 a 96 J b 84 J c 48 J
2 a 30 J b 90 J
3 b and d, since work involves a force and resultant
displacement.
4.6 COPING WITH COLLISION
No answers required.
4.7 MOMENTUM
APPLY YOUR SKILLS
1 Chemical energy (in fuel) is converted to heat and
light energy, and transferred to exhaust and to rocket
as kinetic energy; some kinetic energy of rocket is
converted into gravitational potential energy.
2 6.3 m/s 3 2.8 h 4 1.2 m
5 Chemical energy converted to heat and kinetic energy
of the remaining molecules (carbon dioxide, water
and carbon).
6 78 000 kg m/s
QUESTIONS
1 1.25 kg m/s
2 a 13.6 m/s b 19.4 m/s c 5 m/s
3 Energy consideration alone cannot be used to find the
velocity of a bullet fired at a ballistic pendulum as the
pendulum moves upwards, gaining potential energy
related to the kinetic energy of the combined masses
immediately after impact.
CHALLENGE YOURSELF
Individual student answers required.
Chapter 5 Properties of waves
5.1 WAVE PROPERTIES
QUESTIONS
1 Both sound and light waves possess wavelength,
wavespeed, frequency and intensity, and demonstrate
Heinemann Interactive Science 4
Answers to textbook questions  9
reflection, refraction, diffraction and interference.
Both are a form of energy and can be sensed by
humans.
2
5.3 THE ELECTROMAGNETIC SPECTRUM
QUESTIONS
1 a Microwaves, radio waves.
b X-rays, gamma rays.
2 Same speed (speed of light  3  108 m/s), transverse
waves.
3 a 0.5 m b 2.0 m c 0.8 m d 0.2 m
ACTIVITY
THINK ABOUT
1 Longer wavelength, low frequency waves diffract
more than higher frequency waves. Longer
wavelength waves will spread into regions through
small gaps such as doorways.
1 a 4.3  107 m
b 7.5  107 m
c and d Student answers will vary.
2   1 m, f  3  108 Hz;   10 m, f  3  107 Hz
5.4 VISIBLE LIGHT AND INFRARED
RADIATION: SEEING AND FEELING
QUESTIONS
2 Sound waves are compression waves or longitudinal
waves and require a medium through which to travel.
Light waves are transverse waves and can travel
through a vacuum.
5.2 TWO TYPES OF WAVE
1 Visible: eyes or photographic film; infrared: skin or
some types of photographic film.
2 Laser (light amplification by stimulated emission of
radiation) light is monochromatic (single
wavelength), coherent, and has high intensity. Other
forms of light have a greater mixture of wavelengths,
are not necessarily coherent, and are less intense.
QUESTIONS
1
5.5 OPTICAL FIBRES
QUESTIONS
2 P waves are longitudinal, S waves are transverse.
3 Lower frequency waves have longer wavelength, so
C. Longer wavelength waves diffract more, so C. The
energy transported by a wave is proportional to the
square of the frequency and the square of the
amplitude, so higher frequency waves transport more
energy: A.
4 500 seconds
1 Optical fibres trap light rays by making use of
different refractive indices of adjacent media and the
fact that beyond a critical angle total internal
reflection occurs. The light ray cannot escape the
glass fibre.
2 Copper cables are electrical conductors. Optical
fibres transmit pulses of light rather than electric
currents.
3 Analogue signals are voltage oscillations (timevarying waves). Digital signals have only two states
(high or low, one or zero, on or off) and may be
represented and transmitted using pulses of laser
light.
5.6 HIGH ENERGY RADIATION
QUESTIONS
THINK ABOUT
1 Sound waves require a medium and space is virtually
a vacuum.
2 The slinky spring demonstrates the way energy is
carried in waves. The model does not show the
vibration of the energy particles.
Heinemann Interactive Science 4
1 Cells may be damaged. For example, UV rays can
damage the retina of the eye and skin cells. X-rays
can damage sperm or egg cells. Gamma rays may
damage all types of cells since they have high energy
and are highly ionising.
2 X-rays are absorbed by teeth and bones and can be
detected by photographic film. Images of bones and
teeth may be obtained using X-rays.
3
Answers to textbook questions  10
The applied voltage accelerates electrons which
collide with gas atoms. The atoms become excited,
and when they return to their normal energy levels
they emit ultraviolet (UV) radiation, which is incident
on the fluorescent coating on the inside of the tube.
This material emits visible light when it absorbs UV
radiation.
5.7 MICROWAVES, TV AND RADIO
QUESTIONS
1 Ground and sky waves are reflected by the
ionosphere.
2 Can’t be calculated from information given.
3 A carrier wave transmits specific frequency of radio
waves from a radio station, for example. Modulated
waves result from the voice or music from a
microphone being mixed with a carrier wave.
4 Waves have to pass around or through obstacles such
as buildings and trees. The longer the wavelength, the
greater the diffraction around an object or through a
gap. Television waves have relatively short
wavelengths and experience little diffraction in
comparison to, say, radio waves.
5 Aluminium foil would reflect microwaves, resulting
in little radiation reaching the food. Damage might
also occur due to sparking.
5.8 FROM MORSE CODE TO MOBILES
No answers required.
5.9 CHAPTER REVIEW
APPLY YOUR SKILLS
1 Example: fictitious character Roy G. Biv.
2 Shiny surfaces reflect waves more effectively than
matt and/or dark surfaces. For a thermos the heat is
retained, and for a firefighter’s suit the heat is
reflected.
3 Both possess wavelength, wavespeed, frequency and
intensity, and demonstrate reflection, refraction,
diffraction and interference. Both are a form of
energy and can be sensed by humans.
4 Infrared radiation has a lower frequency and is
therefore less energetic. Exposure time is increased.
Ultraviolet radiation has sufficient energy to break
chemical bonds in cells, causing damage. IR merely
increases their vibration rate and so does no damage
unless the protein molecules vibrate so much that they
lose their shape (cooking).
USING SCIENTIFIC LANGUAGE
Across 3 longitudinal 6 period 7 refraction
8 transverse 10 digital 11 wavelength 13 analogue
Down 1 compression 2 rarefaction 4 trough
5 crest 9 frequency 12 vacuum
CHECK YOUR KNOWLEDGE
Heinemann Interactive Science 4
Chapter 6 Under control
6.1 THE NERVOUS SYSTEM
QUESTIONS
1 Neurones are able to make electrical signals and
transmit them.
2 Coin  optic nerve  brain  motor neurone 
effector muscle  arm picks up coin.
3 Reflexes are involuntary actions as there is no
conscious thought involved. The message pathway is
between the receptor and the effector via the spinal
cord directly and not via the brain.
4 The blinking reflex is required to prevent injury to the
eye, e.g. keep out dust and foreign objects.
Answers to textbook questions  11
6.2 THE BRAIN—COMMUNICATIONS
CENTRE
QUESTIONS
1 To pass messages from one nerve to the next.
2 Loss of movement on the right-hand side of the body;
problems with speech; memory loss.
3 Both cause neurones to become more active.
Evidence: amphetamine increases their levels and
causes increased alertness and activity.
4 Fly spray could interfere with the operation of the
neurotransmitters, thereby preventing normal transfer
of nervous impulse, resulting in erratic behaviour.
message systems in the body that allow it to respond
to changes. Both are subject to feedback control.
2 Those cells are the target cells, and have receptors on
their membranes that detect the hormone. Other cells
do not have these.
3 Hormones control the levels of calcium in the blood.
Note: Soluble calcium is found in the bloodstream
and in an insoluble form is found in bones.
Parathormone, from the parathyroid gland, causes
insoluble calcium to be converted to soluble calcium.
Calcitonin from the thyroid has the opposite effect.
Twitching is due to an underactive parathyroid gland.
6.6 CONTROLLING GLUCOSE LEVELS
6.3 PSYCHOACTIVE DRUGS
QUESTIONS
QUESTIONS
1 Absorbed into the bloodstream from our food in the
gut (intestine).
2 Energy—extracted from glucose by cellular
respiration.
3 Pancreas and liver (also muscles, but these are not
organs as such).
4 Liver and muscle cells.
1
6.7 RECENT ADVANCES IN TREATING
DIABETES
QUESTIONS
2 Alcohol, tobacco (nicotine), caffeine, and
prescription-only drugs for medicinal purposes
(e.g. cocaine).
3 Alcohol and tobacco should be included in
discussions on drug taking as they are addictive
stimulants and have health/social implications.
6.4 SMART DRUGS
No answers required.
6.5 CHEMICAL MESSENGERS
QUESTIONS
1 Substances that carry messages in the body. They are
transported in the bloodstream.
2 It releases hormones that control some other
endocrine glands, e.g. thyroid.
3 Cells that detect a hormone and respond to its
message.
4 The element iodine is a part of the hormone
thyroxine.
THINK ABOUT
1 The body can respond to different types of stimuli.
Nerves: quick response; short acting; affect a small
area of the body. Hormones: slower response that
lasts longer; can affect many areas of the body. Both:
Heinemann Interactive Science 4
1 Genetic engineering—the gene that codes for insulin
is taken from human cells and spliced into bacterial
DNA.
2 Large amounts can be made at low cost. It is also
human insulin.
3 Coating islet cells with a protective capsule of semipermeable membrane, preventing the entry of
antibodies or white blood cells that attack the islet
cells.
6.8 KIDNEYS—THE AMAZING FILTERS
QUESTIONS
1 Pituitary releases anti-diuretic hormone (ADH). It
releases more to cause more water reabsorption when
the body’s water level is too low.
2 Reabsorption is taking a substance back into the
bloodstream. Glucose and amino acids—they are
useful and the body does not want to lose them. Water
and salt—a certain amount of each is reabsorbed to
maintain the correct levels in the bloodstream.
3 Less volume, more concentrated.
Stimulus (increase in salt in blood)  detected by
receptors in the brain  pituitary releases more ADH
 more water reabsorbed  less urine.
4 The kidneys maintain the correct levels of salt and
water in the body fluids by controlling how much of
each is excreted.
Answers to textbook questions  12
THINK ABOUT
Alcohol and caffeine block the release of ADH
(diuretics), and so more urine is produced. The body is
therefore losing even more fluid.
6.9 CONTROL OF BODY TEMPERATURE
QUESTIONS
1 a Detect a change in body temperature.
b Cools the body when sweat evaporates.
c Warms the blood as a result of heat produced by
muscle action.
2 Dehydration, exertion, high environmental
temperature.
3 As muscle tissue broke down it released toxic
substances. These poisoned other organs.
THINK ABOUT
Receptors are continually monitoring the body
temperature and causing adjustments when it falls or goes
above a certain temperature. Mechanisms to conserve or
lose heat are switched on and off accordingly. A
thermostat gauges the temperature and turns a heating or
cooling process on or off accordingly.
c Hormone: chemical released from endocrine
glands that causes an effect in other body cells.
d Psychoactive drug: one that has an effect on the
brain and so affects behaviour. (Note: these drugs
cause changes in brain chemistry, i.e. affect
neurotransmitters.)
2 a Stimulus: touching a hot object. Response:
moving hand away rapidly.
b Receptor: detects change, e.g. thermoreceptor.
Effector: carries out the response, e.g. sweat
glands.
c Endothermic: produces enough heat to warm the
body above environmental temperature, e.g.
mammal. Ectothermic: does not produce enough
heat to warm the body above environmental
temperature, e.g. reptile.
d Vasodilation: skin arterioles becoming wider to
allow more blood to the skin. Vasoconstriction:
opposite. More blood to the skin increases heat
loss and vice versa.
e Phototropism: plant shoot growing towards the
light. Gravitropism: plant root growing
downwards.
CHECK YOUR KNOWLEDGE
6.10 PLANT RESPONSES
QUESTIONS
1 Tropism is directional growth as a response of a plant
to the environment. Plants respond to light intensity
and colour; gravity; temperature; day length.
2 Plants need to be able to detect a light source to grow
towards it, since plants need light to survive. They
also will only grow in certain colours of light.
3 So that the roots will grow into the soil for anchorage
and the shoots will grow towards the light—
especially important when the seed is germinating.
4 Gravity is detected by cell (stimulus)  auxin
accumulates on low side of stem  stem is forced to
bend up (response).
THINK ABOUT
Can cause plants to grow bigger and faster; increased
yield. Could control when plants flowered—could have
some flowers all year round. Important for horticultural
industry.
6.11 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
1 a Homeostasis: maintaining stable internal
conditions.
b Neurotransmitter: a substance that carries
messages from one nerve to another in the brain.
(Note: can also be called ‘transmitter’.)
Heinemann Interactive Science 4
APPLY YOUR SKILLS
1 a Slows down—molecules have less energy,
therefore move less, resulting in fewer collisions.
b Chemical activity in the brain slows (e.g.
neurotransmitter production), therefore brain cells
cease functioning at required rate.
Answers to textbook questions  13
2 Stimulus (decrease temperature)  thermoreceptors in CNS



response (body warms)


effectors (muscles)
(Flowchart could also incorporate vasodilation.)
3 Include: healthy green leaves; leaves change colour as
nutrients, chlorophyll, water are removed; wastes are
put into leaves; abscisic acid builds up; ‘dead’ leaf
drops off at stem.
4 In the body, the incoming message will be received at
one end of the neurone where there are receptor sites.
The message can only go one way, or it would
cross/cancel out a message coming the other way.
This would be chaotic (cf. wiring in any appliance).
7.2 ENZYMES—CATALYSTS OF LIFE
QUESTIONS
1 Enzymes are proteins that speed up the rate of a
specific chemical reaction within a living organism;
therefore they are called biological catalysts.
2 The active site is the place or point on the substrate
onto which the enzyme locks.
3 Each enzyme is specific to one substrate—because of
the shape of the molecules they fit each other exactly,
like a key to a lock.
THINK ABOUT
CHALLENGE YOURSELF
1 For example, kidney function: nerves detect stimulus,
and send message to pituitary gland. This causes the
hormone (ADH) to be released. (Could also describe
temperature regulation involving pituitary and thyroid
glands.)
2 Insert a gene into the cells that will make them
manufacture the required hormones, or factors. The
gene would be taken from plants grown in the
required climate.
3 Specialised drinking solutions, ‘cool vests’.
4 Individual student answers required.
1 Because the active site on the sucrase molecule (the
enzyme that acts as a catalyst to break up sucrose)
does not fit the substrate maltose, it only fits
sucrose—just as the active site on the maltase enzyme
only fits maltose.
2 If the molecule has been unravelled (or denatured),
the active site will have been destroyed; thus it will
not ‘fit’ the substrate.
3 As a true catalyst an enzyme does not alter the
products of the reaction. If it is involved in up to
5 million reactions per minute, it will not be possible
to manufacture new enzyme for each new set of
reactions.
Chapter 7 Sport science
7.3 RESPIRATION—RELEASING ENERGY
7.1 AN ATHLETE’S DIET
QUESTIONS
QUESTIONS
1 Aerobic—respiration that requires oxygen;
anaerobic—breakdown of glucose without using
oxygen.
2 Build-up of lactic acid makes the muscles stiff.
1 The liver stores glucose as glycogen.
2 Cellulose and lipids.
3 Lipids also insulate the body and they are energy rich
and can be converted directly to release energy.
4 a Amino acids.
b Fatty acids (triglycerides) and glycerol.
5 A sprinter requires readily available energy such as
that obtained in drinks containing glucose. A long
distance runner requires a more steady level of energy
and would probably consume more complex
carbohydrates such as potato and bread. More recent
research shows that dairy products, lentils, oats and
apples prior to an event provide steady levels of
glucose.
THINK ABOUT
THINK ABOUT
1 Oxygen is required to release chemical energy from
glucose to produce movement; therefore during
exercise more oxygen is required.
2 Both glycogen and fat store energy that can be used
when supplies of glucose are low or when extra
energy is required for the unusual activity. Glycogen
can be easily converted to glucose; it takes longer to
release the energy from fat.
3 Energy is needed for basic body processes that
continue during sleep—heartbeat, breathing, nervous
system, etc.
To prevent vitamin deficiencies that could cause disease.
Answers could reflect awareness that a balanced diet
should provide adequate vitamins.
7.4 RESPIRATION AND HUMAN
PERFORMANCE
QUESTIONS
1 ATP, aerobic respiration, anaerobic respiration.
2 ATP—ATP molecules; aerobic respiration—glucose
and oxygen; anaerobic respiration—glucose.
3 To supply all cells with oxygen and glucose and
remove waste products (such as carbon dioxide and
Heinemann Interactive Science 4
Answers to textbook questions  14
lactic acid), which are toxic to cells if allowed to
build up.
7.7 PERFORMANCE-ENHANCING DRUGS
THINK ABOUT
THINK ABOUT
1 a Aerobic. b ATP. c ATP.
d Anaerobic/aerobic. e Aerobic.
2 a 200 m race—ATP; 800 m race—anaerobic;
1500 m race—anaerobic; marathon—aerobic.
b The 200 m race will take around 30 s, requiring
immediate energy from stored ATP molecules.
Aerobic respiration starts about 3 minutes into
exercise, so after the initial ATP start to the 800 m
race most of the energy is supplied by anaerobic
respiration. In the 1500 m race the body still has
not had sufficient time to start supplying aerobic
energy, so most is supplied by anaerobic
respiration. The marathon generally takes over
3 hours, so a well trained body will be provided
with the energy through aerobic respiration.
c As the events become longer there is more time
for aerobic respiration to take over from anaerobic
respiration.
Individual student responses required.
7.8 CAREERS IN SPORT SCIENCE
QUESTIONS
1 Slow motion videos can help athletes analyse their
technique so they can improve it, e.g. a golfer’s swing
or a swimmer’s stroke, kick or turn.
2 a High protein to build muscle.
b High carbohydrate for energy.
3 a Leg muscles, knee.
b Ankle, knee, muscle.
c Shoulder, arm.
THINK ABOUT
Motivation, positive thinking, focusing on the ‘game
plan’, relaxation.
7.5 SCIENCE TRAINS THE ATHLETE
7.9 CHAPTER REVIEW
QUESTIONS
USING SCIENTIFIC LANGUAGE
1 Sprinter would probably have a lean body, long legs
with fast twitch muscles. A long distance runner
would have a lean body, could have shorter legs and
slow twitch muscle, possibly a lower centre of
gravity.
2 Student’s own response required.
3 Cyclists lean their bodies forwards and hold them
close to the cycle to reduce drag forces. Streamlined
helmets, smaller front wheels and narrow bikes all
contribute to less drag.
glucose—broken down to release energy
glycerol—part of a lipid molecule
amino acids—make up protein molecules
DNA—genetic code molecule
ATP—energy carrier molecule
catabolism—molecules breaking down to simpler ones
CHECK YOUR KNOWLEDGE
7.6 ENERGY TO BUILD BODIES
QUESTIONS
1 Anabolism—synthesis reactions in which substances
are produced and energy is used, e.g. protein
synthesis from amino acids.
Catabolism—reactions in which substances are
broken down and energy is released, e.g. oxidation of
glucose.
2 Energy is used to synthesise complex molecules out
of simpler substances.
THINK ABOUT
1 Any chemical reaction related to cellular respiration.
2 Hair is composed of protein.
Heinemann Interactive Science 4
Answers to textbook questions  15
APPLY YOUR SKILLS
1 Each student will need to use his/her own body
weight. Using 60 kg as an example the person would
contain:
water—60  0.65 = 39 kg;
protein—60  0.18 = 10.8 kg;
fat—60  0.1 = 6 kg;
carbohydrate—60  0.05 = 3 kg;
minerals—60  0.01 = 0.06 kg;
other—60  0.1 = 0.6 kg.
2 By testing the products of the reaction or by
separating the products of the reaction and reusing the
enzyme to see if it still acted as a catalyst.
3 Complex carbohydrate (e.g. starch in pasta) is
digested using enzymes to form glucose; glucose in
muscles is broken down during cellular respiration to
provide energy.
4
Chapter 8 Natural selection and
evolution
8.1 A TIME FOR CONTROVERSY
QUESTIONS
1 Unusual tortoises and giant iguanas.
2 Marine iguanas have different colours and markings,
depending on which island they are found on. Blunt
nose and serrated teeth adapted to eating algae were
found on the Galapagos Islands iguanas only.
3 Darwin realised that his ideas would be very
controversial and wanted to gather as much evidence
as possible to support his arguments.
4 Charles Lyell—suggested that most landforms had
formed slowly, supporting slow change/evolution in
species. Thomas Malthus—suggested that growth in
human populations slowed due to war, famine and
disease, supporting a ‘struggle for existence’ applying
to species other than humans.
5 Darwin has been given credit for the theory rather
than Wallace as he published his book first and made
it widely known, resulting in scrutiny from the clergy
and the wider scientific community at the time,
whereas Wallace had only put his ideas forward in a
journal essay and so was not so well known.
THINK ABOUT
Individual student responses required.
CHALLENGE YOURSELF
1 a Not sufficient oxygen supplied to muscles;
therefore anaerobic respiration takes place to
supply energy. The lactic acid that is a product of
this reaction builds up, causing muscle stiffness.
As fitness improves, so does the body’s ability to
supply oxygen to the muscle cells.
b Oxygen supply increased; therefore more efficient
aerobic respiration; therefore less anaerobic
respiration and less lactic acid build-up.
2 Students’ answers will vary.
3 a Soccer players: low centre of gravity, slow twitch
muscles, flexible.
b Volleyball players: tall, slow twitch muscles, lean
body.
c Gymnasts: low centre of gravity, fast twitch
muscles, flexible.
d Rugby league players: low centre of gravity,
strong build, slow twitch muscles.
e AFL players: long legs and arms, flexible, slow
twitch muscles.
8.2
DARWIN’S FINCHES
QUESTIONS
1 Seeds would have been carried by water, wind and
bird droppings to the islands. Small animals may have
arrived by floating on objects or being washed up
from neighbouring landmasses.
2 The finches all had different beaks, adapted for the
particular feeding habit suited to their respective
islands.
3 The woodpecker finch may not have been
endangered, as the woodpecker may not have
survived, because there were no large trees in which
insects could live/hide. The woodpeckers would have
had to collect them a different way, to which their
beaks may not have been adapted.
8.3 ARTIFICIAL SELECTION
QUESTIONS
1 Breeder has a predetermined outcome, and so selects
which animals to breed with to achieve this.
2 Better quality meat, e.g. more protein and less fat;
financial advantage to farmer; ability of animals to
grow more efficiently (in farmer’s terms).
Heinemann Interactive Science 4
Answers to textbook questions  16
3 In the wild, animals choose their mate (using their
criteria), instead of being chosen by a breeder
(farmer).
THINK ABOUT
features have become unfavourable. (This
explanation applies even if they have been killed by
the action of humans.)
2 Genetic engineering; selective breeding; altering the
environment (some species adapt well, others
cannot).
Individual student responses required.
8.7 EVIDENCE FOR EVOLUTION
8.4 NATURAL SELECTION
QUESTIONS
QUESTIONS
Tall thin trees (alpine ash) are competing for light, not
water—short, slow-growing plants would be selected
against in this environment. Snow gums have thin,
flexible branches that bend under the weight of snow and
do not break; their open structure means they do not
carry a great burden of snow. River red gums have thick
trunks for their height and are able to withstand the
buffeting of flood waters; their strong roots anchor them
securely in waterlogged soils. Mallee gums are
competing more for water; their limbs are shaped so that
water runs towards the base; they are more sparse since
water is a limiting factor.
1 Fossil record matches the principles of the theory.
Comparative anatomy—similarity of structures in
related species. Comparative embryology—
similarities in embryos of related species.
Biogeographical—similarities in the fossils, flora and
fauna found on different continents.
2 60 million years ago it was about 400 cm tall, with
four toes per foot. By 40 million years ago it had
evolved into a three-toed 600 cm form. About
30 million years ago it was about 1 m tall. It evolved
into the present-day form standing at 1.6 m, with one
toe (hoof) per foot.
3 Examination of the types of plant fossils and the types
of rocks found in the same layers; examination of the
teeth (whether adapted for soft or harsh vegetation,
for browsing or grazing).
4 Marine sediments provide a better environment for
preservation; greater chance that organisms will be
buried in the oxygen-poor environment before
decomposition can take place.
8.5 TWO DIFFERENT THEORIES
8.8 NEW FORMS OF EVIDENCE
QUESTIONS
QUESTIONS
1 Need: a circumstance that arises during a lifetime.
Acquire: obtain a feature during a lifetime. Variation
exists: members of a population are not genetically
identical. Select: individuals with favourable
variations are more likely to survive and reproduce.
2 Evolution is the theory that the characteristics of
species change over time, with some species
disappearing (extinction) and new species arising.
Natural selection is the process or mechanism by
which evolution occurs.
3 Students answers will vary.
1 Comparison of the degree of similarity of the genes of
different organisms by matching up strands of their
DNA.
2 Heated to a specific temperature.
3 Genes have a certain sequence of bases—the
complementary sequence will be on the other strand.
Bases on the strands always join A–T, G–C. The more
closely related the organisms, the more likely they are
to have a similar set of genes and similar sequences of
bases.
4 Comparing the amino acid sequences in certain
proteins, e.g. enzymes, haemoglobin. (Done by
electrophoresis—also used for DNA fingerprinting.)
1 Better able to cope with the environment and so more
likely to survive to reproduce.
2 Rabbits have changed since the 1950s by becoming
more resistant to the myxoma virus.
THINK ABOUT
8.6 NEW SPECIES
QUESTIONS
THINK ABOUT
1 Change in the characteristics of a species over time.
(Note: this does not imply anything about the rate.)
2 a convergent b parallel c divergent d divergent
e convergent f parallel
1 Closely related—DNA hybridisation can distinguish
even the most minor differences. The differences
between distantly related organisms can (usually) be
determined easily, although DNA hybridisation may
clarify confusing cases of convergent evolution.
2 Look similar. At the time, scientists did not have
access to DNA hybridisation or biochemical
techniques and could only base their conclusions on
structures.
THINK ABOUT
1 They are selected against, and the species as a whole
cannot cope with the rate of change required. Their
Heinemann Interactive Science 4
Answers to textbook questions  17
8.9 SIMILAR BUT DIFFERENT—SOURCES
OF VARIATION
QUESTIONS
1 There is a random separation of chromosome pairs
during meiosis. One chromosome from each pair goes
into each daughter cell at the first division. This is the
same for each pair, so for 23 pairs there are 223
possible combinations. This is the same for both male
and female gametes, so at fertilisation there is an
enormous number of possible combinations (223
squared).
2 Accidental change in a gene—occurs when the DNA
is being replicated. It gives rise to a new gene which
may be passed on to offspring, giving greater
variation in the phenotype of the species.
3 Hair colour—genetic (unless dyed or bleached by the
sun).
Eye colour—genetic.
Height—genetic (may be influenced somewhat by
dietary deprivation or ill health).
Sex—genetic.
Good at science—combination (can debate the
relative input of each factor).
Fast at swimming—combination (can debate the
relative input of each factor).
THINK ABOUT
1 If a disease or environmental change occurred it
could devastate the population if they were
genetically identical—all would be affected equally.
However, if there is variation then some may have a
feature that would enable them to survive and breed
(variation gives the species flexibility to cope with
change).
2 Mutation may give rise to a feature that makes the
organism better able to survive. The organism will
then pass the gene onto its offspring and so confer the
advantage on them. It would then become more
common in ensuing generations.
3 Genetic variation is more fixed than the environment,
which can change rapidly and unpredictably. Genetic
factors can be passed on, whereas changes caused by
environmental factors cannot be passed on (e.g.
suntan).
8.10 ROCKS TELL A STORY
QUESTIONS
1 Ammonites (Jurassic rocks), graptolites (Ordovician
rocks). Index fossils are distinctive fossils deposited
over a short period of geological time. They are
important because they can be used to identify rocks
of similar age.
2 a Sedimentary rocks, because they have not been
exposed to the extremes of heat and pressure that
igneous and metamorphic rocks have.
Heinemann Interactive Science 4
b Igneous and metamorphic rocks, due to the
mountain-building activity that resulted in the
formation of the landmasses.
3 Organisms were single-celled or soft-bodied, so were
difficult to fossilise.
4
8.11 HUMAN IMPACT ON EVOLUTION
QUESTIONS
1 218  262 144 cells; 230  1 073 741 824 cells.
(There are 18 lots of 20 minutes in 6 hours and
30 lots in 10 hours.)
2 All that is needed is one bacterium from a colony to
be resistant for it to form a new resistant colony. Each
time an antibiotic is used, there is a chance of
selecting for this bacterium. (Note: there has been
much debate recently about the routine use of
antibiotics in animal food, especially with MRSA—
multiply-resistant Staphylococcus aureus—
developing.)
3 Reducing variation could produce a monoculture,
which can lead to crops being wiped out by one
pest/disease, as no crops would exist with a variation
in the form of resistance to the particular pest/disease.
THINK ABOUT
1 To prevent a bacterial type from becoming resistant to
one antibiotic. The more times one type of antibiotic
is used, the greater the chance of selecting bacteria
with resistance to it. (An alternative answer is that the
first antibiotic was ineffective due to resistance.)
Often ‘combination antibiotics’ are taken.
2 To try to ensure that all the bacteria die, and as
quickly as possible. This reduces the chances of
selecting for bacteria that may be resistant to any
degree.
8.12 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
1
2
3
4
5
6
7
8
9
10
Phylogeny.
Artificial selection.
Variation.
Meiosis.
Mutation.
Evolution.
Biodiversity.
Convergent evolution.
Adaptation.
Divergent evolution.
Answers to textbook questions  18
CHECK YOUR KNOWLEDGE
4 Wild pigs—they show more variation within the
population. Others have been subjected to artificial
selection which reduces the genetic variability. Also,
the features selected by artificial selection may not be
the ones needed to survive in the wild.
5 Sugar gliders—koalas have evolved to have a highly
specialised diet. If those trees were to become less
common due to some factor then the chances of
koalas surviving would be greatly reduced. Sugar
gliders have evolved to have a varied diet, so are not
reliant on one other species.
CHALLENGE YOURSELF
1 a Study their habitats and distribution; maybe gather
fossil evidence; compare similar structures (e.g.
wings); maybe compare their embryos at various
stages of development.
b DNA hybridisation: comparison of genes and
proteins (electrophoresis or ‘genetic
fingerprinting’); also do comparative anatomy
studies, and compare their biogeography.
2 Similarities include general body plan, feet, wings,
legs. Differences include size; tail, forelimbs and
teeth in Archaeopteryx; structure of pelvis and
sternum. Answers will challenge students to define
‘bird’; comparison with modern species would need
to be structural as there is little chance that any DNA
has been preserved.
APPLY YOUR SKILLS
1 Rabbits breed faster than kangaroos; therefore there
are more offspring and greater consequent chance of
variation, i.e. an offspring that has a mutation that
makes it immune to the virus. (Note: the myxoma
virus also evolved into a non-pathogenic form.)
2 By artificial selection, breeders have deliberately bred
pairs of birds that showed slight variation from the
standard green colour. The end result over many
generations has been the emergence of the different
coloured birds. In the wild this does not occur. In the
absence of factors selecting for colour variation, any
genes for different colours will not become common
in the wild. It is likely that the different colours are
selected against, i.e. that green is selected for by
natural selection, possibly because it provides
camouflage.
3 a Sexually—mutation, meiosis, fertilisation.
Asexually—mutation, also exchange of plasmids
in bacteria.
b Yes—expect a greater variation in sexual
reproduction because there are more sources of
variation (see answer to part a). This however
may be offset by asexually breeding organisms
having a faster breeding rate (e.g. bacteria),
therefore more chance of variation due to a
mutation arising.
Heinemann Interactive Science 4
Chapter 9 Our precious
resources
9.1 ENERGY RESOURCES
QUESTIONS
1 a Limited, not infinite, will be used up.
b Able to be maintained/kept up.
c Stores retained for later use.
d Process of using up.
Student sentences for each of the parts will vary, as
will the above phrases.
2 Renewable resources can be replenished, e.g.
plantation timber, air, water. Non-renewable resources
will not be replaced in the near future or even our
lifetime, e.g. mineral resources, fossil fuels, soil.
3 Current rate of use of non-renewable resources is not
sustainable. Old growth forests are being cut down,
soil has been degraded, waterways polluted. Nonrenewable resources are being run down. World
reserves of oil and natural gas are expected to become
scarce this century.
THINK ABOUT
1 Anaerobic bacteria producing alcohol by
fermentation, tidal movements, water running
downhill.
2 Student’s own answer required.
Answers to textbook questions  19
THINK ABOUT
9.2 FOSSIL FUELS
QUESTIONS
1 Sun  plants lock up energy from Sun as chemical
energy through photosynthesis  animals eat plants
to obtain chemical energy  plants and animals die
locking away the chemical energy as coal.
2 Lignite or brown coal has a higher water content than
anthracite or black coal, which is a higher grade fossil
fuel as it is more compact.
3 a Source rock is the rock in which the oil formed.
Reservoir rock is the rock in which the oil
collects.
b They would be porous sedimentary rocks.
c Caprock is impermeable, so the oil or natural gas
cannot pass into or through it. It forms a barrier to
the movement of oil, water and gas.
4 Seismic surveillance.
9.3 ELECTRICITY FROM THE SUN
QUESTIONS
1 Solar radiation used to heat objects that are exposed
to the radiation (these are generally black)  steam
produced used to drive a turbine to generate
electricity.
2 Incoming energy causes changes in electron
associations of atoms in the photovoltaic material 
regions of electron excess and electron deficiency are
created  electrons flow in a circuit due to this
potential difference.
THINK ABOUT
The intensity of the Sun’s light is greatly reduced at large
distances (inverse square proportionality), so the efficacy
of solar cells near Pluto will be greatly reduced.
9.4 MINERAL RESOURCES
QUESTIONS
1 Diamonds are very rare, but because nothing is
harder, they do many jobs that no other substances
can do. They only occur in a few places in the world,
therefore companies can demand high prices. This
makes small amounts viable.
Iron ore is not rare. Therefore, buyers have
alternatives, and can keep the price low. Thus, the
deposit has to be big to make enough money to keep
going.
2 Gold—fillings for front teeth; iron—frames for highrise buildings; aluminium—aeroplane bodies;
copper—electrical wiring.
Heinemann Interactive Science 4
1 Like the outdoors, be interested in rocks and
minerals, be willing to endure harsh conditions, be
observant and thorough. They would have to walk
and collect specimens, read maps, identify minerals in
the field, compile reports. They could be sent to very
remote desert areas, or rainforest, or on the fringes of
cities—just about anywhere.
2 Even though gold and silver are often much valued,
and copper is easy to work with, iron is valued the
most because it is used for so many things and in
large amounts.
9.5 MINING AN ORE BODY
QUESTIONS
1 Shallow, near-flat lying, horizontally extensive.
2 When the ore body is deep, near-vertically orientated,
or the area at the surface cannot be significantly
disturbed for some reason.
3 Open cut leaves the most surface scarring. These
mines could be recontoured and made into parks,
lakes, golf courses, building estates, etc.
4 At first it allows access to the top of the ore body,
then the rock from the open cut is used to back-fill
underground workings after mining is finished.
9.6 MINING HAS ITS COSTS
QUESTIONS
1 Collapse—ensure wall or tunnel shape is correct, and
rock types are known and surveyed.
Flooding—accurate mapping of groundwater,
knowledge of local rainfall.
Dangerous gases—adequate detection devices and
checks.
Damage to miners’ ears due to excessive noise—
compulsory and adequate hearing protection.
Lung damage—damping down drilling and
explosions, face masks, monitoring dust levels.
Environmental damage—thorough mapping,
monitoring and understanding of local environment
and habitats.
2 Human—respiratory, hearing or other discomfort (or
damage), loss of productive land, dissatisfaction with
the appearance of the mine, contamination of air or
water. Non-human—frightened by noise, dust
inhalation, food or water contamination, loss of
habitat.
Unsightly appearance and loss of habitat may be
unavoidable in some cases.
Noise can be reduced by building earthworks around
the mine site, or having the noisiest parts of the
process (e.g. crushing) underground.
Dust can be controlled by continually damping down.
Contamination can be controlled by isolating systems
from the environment, and/or treating wastes before
releasing them.
Answers to textbook questions  20
THINK ABOUT
1 To establish the range and vulnerability of local
species of wildlife (or human population) and cater
for any disturbance that might occur with mining.
2 To make sure the local wildlife or human population
is not being adversely affected by noise, dust,
chemical contamination.
3 To ensure that rejuvenation is occurring, and help
with responsible planning for the next venture.
3 a Near the sea or other surface water body.
b Water table and ground surface.
c The creek, because it is flowing and would spread
the spill downstream. The sea, because the water
in the aquifer moves ‘downhill’ just as surface
water does.
9.10 SALINITY
QUESTIONS
9.7 FROM ROCKS TO MINERALS
QUESTIONS
1 A rock is a mixture (of minerals) and a mineral is a
compound or an element. A rock can be physically
broken down into simpler substances, whereas a
mineral can only be broken down chemically (if
at all).
2 Whole rock uses in this section—weapons, tools,
ornaments, house construction, gravestones, statues,
table tops and slate tiles; others—paving stones,
garden landscaping, shelter (caves), roadmaking.
3 So that we can extract only those minerals which
contain the valuable elements from the rest, prior to
further refining.
4 Magnetic ore separator picks out only those few
minerals which are attracted to magnets; as there are
very few magnetic minerals, this is limited.
9.8 FROM MINERALS TO ELEMENTS
QUESTIONS
1 An element is the simplest pure substance. A mineral
is a solid, naturally occurring compound or element,
so, yes, a substance can be both an element and a
mineral.
2 Some metals are very stable—that is, they stay in
element form rather than combine with other
elements—while others are very reactive and readily
form bonds with or lose electrons to other elements.
3 Metal elements high in the activity series would
‘much rather’ exist as ions in compounds with other
atoms (as shown by their reactivity), and so it takes a
lot of ‘chemical persuasion’ to force electrons back
onto the metal ions to give the metal element.
4 Potassium, and other elements high in the series,
because they would take the most chemical
processing, and electrolysis (which would require
large amounts of energy).
1 a The groundwater flowing through the aquifer
dissolves minerals from the rock or sediment as it
goes. If the aquifer material is salty, the water will
become saline.
b Trees keep the water table down. If they are
removed, the water migrates up through the
sediment to the surface, dissolving minerals
(including salt) as it goes.
c Irrigation also raises the water table, through the
salty sediments.
2 Stop clearing land of trees; do not over-irrigate;
replant native, deep-rooted, salt-tolerant vegetation.
THINK ABOUT
1 Constants—size of electrodes, depth of electrode
immersion and distance apart; same beaker; beaker
and electrodes washed between samples.
2 Salt-tolerant species would establish ground cover
and prevent further erosion. Could also force water
table to stay low before it rises and gets too salty.
9.11 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
a
b
c
d
e
f
Ore mineral.
Geothermal.
Reservoir rock.
Ore body.
Geophysicist.
Aquifer.
CHECK YOUR KNOWLEDGE
9.9 HIDDEN WATER
QUESTIONS
1 ‘Hidden water’ is water that is underground, so we
usually cannot see it in its ‘natural habitat’.
2 Aquifer refers to the whole layer of sediment or rock
that is saturated with underground water. The water
table is the upper surface of this layer.
Heinemann Interactive Science 4
Answers to textbook questions  21
that the Big Bang origin of the Universe should have
generated.
APPLY YOUR SKILLS
1 a 2.5  1000  2500 g
b 1700  2500  100  68%
2 a Iron is fairly high on the activity series, which
means it readily reacts with other elements. Out in
the open it would be exposed to air (containing
oxygen) and water (containing oxygen and
hydrogen).
b Rust is therefore likely to be an iron oxide or iron
hydroxide.
3 How particular the governing bodies are at the time,
what type of new land use the area is being made
available for, whether the soil has been contaminated,
what type of climate the area has (i.e. how much help
plants need to establish), what state the land was in
before mining started (often it was in a very poor
state, and the required level of productivity after
mining far exceeds its level before mining).
Chapter 10 Studying the Universe
10.1 COSMOLOGY
QUESTIONS
1 A nebula is a cloud of gas and dust in space between
the stars. A galaxy is a dense band of stars.
2 The Andromeda galaxy was thought to be a ball of
gas until the 1920s because the telescopes available
were not powerful enough to be able to tell otherwise.
3 Hubble proposed that the Universe is expanding all
the time. Einstein proposed the theory of relativity
dealing with gravitation, space and time. Lemaitre
formulated the modern Big Bang theory, which
explains the observation that galaxies are moving
away from each other.
4 Hubble, using the Doppler effect, found that other
galaxies are moving away from the Milky Way, and
the further they are the faster they move, indicating
that the Universe is expanding.
THINK ABOUT
1 Light that we observe has taken a great deal of time to
reach us from distant stars and galaxies. We are
observing events that may have occurred millions of
years ago.
2 Perhaps the orientation of the Earth has changed
slightly so that our viewing position has altered.
10.3 STARS
QUESTIONS
1 Hydrogen, the lightest element.
2 Large clouds of interstellar matter  gravitational
attraction clumps matter  mass and temperature
increase due to high speeds of closely compacted
particles  nuclear fusion occurs with hydrogen as
fuel (a star is born!)  gases heated by nuclear fusion
produce outward pressure that is sufficient to halt the
gravitational collapse  expansion and gravity
balance causing stability of star (now in the main
sequence).
3 The mass of the original body determines the path of
evolution. Hydrogen is used up  star collapses 
red giant formed  outer layers expand and cool 
nuclear reactions cease  star collapses due to
gravitational force  white dwarf formed  cools
and collapses  then black dwarf. A star of greater
mass than our Sun may follow a different
evolutionary path and may become a neutron star,
black hole or supernova.
4 A pulsar emits radio waves as it rotates and these are
detected as pulses as the beam sweeps past the Earth.
5 A white dwarf is a small visible star of low
luminosity. A black dwarf is smaller still, having
cooled and collapsed, and has even lower luminosity.
THINK ABOUT
600 years before observation in 1054, so in the year 454.
10.2 THE ORIGIN OF THE UNIVERSE
QUESTIONS
10.4 DESCRIBING STARS
1 Big Bang: matter, space and time come into being
simultaneously; matter exists in an incredibly dense
core; explosion occurs; matter thrown outwards in all
directions; uneven distribution of matter; gravitational
force in more dense regions results in dense clouds of
gas; stars, galaxies and other celestial bodies formed
within these clouds; matter continues to move
outwards as space expands at high speed.
2 Galaxies are the result of gravitational attraction of
slightly more dense regions of mass from the Big
Bang explosion.
3 Detection of hydrogen and helium in low densities in
intergalactic space; redshift of light emitted by distant
galaxies; detection of the cosmic microwave radiation
QUESTIONS
Heinemann Interactive Science 4
1 Absolute magnitude is the brightness of a star as if it
were at a distance of 10 parsecs from Earth. Apparent
magnitude is the observed brightness in the position
in which it is observed. Apparent magnitude of 6 is
just visible to the naked eye, brightest visible stars
have apparent magnitude of about 1, and the Sun
has an apparent magnitude of 27.
2 Astronomers use colour (spectral type),
corresponding to temperature, brightness and size.
These can be plotted on the H–R diagram.
3 Blue star.
4 About 5500C (yellow).
Answers to textbook questions  22
10.5 THE SUN IS A STAR
QUESTIONS
1 A hydrogen nucleus consists of a single proton.
2 Deuterium still has only one proton but it has extra
mass in the form of a neutron.
3 23 He has one less neutron in the nucleus than 42 He .
4 Two protons are used in the first reaction and one
used in the second reaction. Two protons are
produced in the third reaction.
5 The cycle starts with protons joining by nuclear
fusion and the end products of the cycle also include
protons.
10.6 THE SUN—ITS SIZE AND
COMPOSITION
QUESTIONS
1 Atoms produce an emission spectrum when they
release light energy (photons). These packets of
energy are released with certain discrete values
corresponding to the differences in electron energy
levels of the atom as electrons drop energy levels
towards the ground state. To excite electrons, atoms
must be subjected to incoming energy (radiation).
2 Emission spectra appear as bright lines on a black
background as the light energy is released at certain
frequencies which correspond to certain colours.
Absorption spectra appear as dark lines on an
otherwise complete colour spectrum since only
certain frequencies are absorbed by electrons within
an atom in reaching a higher energy level.
3 The spectrum of light from a star can be determined
using a spectroscope, by examining the emission and
absorption spectra. Lines that correspond to lines of
emission spectra of known elements indicate that
these elements exist in the star since spectral lines are
unique for each element.
4 A radio telescope would be most useful in collecting
information about pulsars since they emit radio waves
(non-visible, low frequency).
THINK ABOUT
1 Infrared telescopes provide information about the
heat emitted by an object.
2 Both types of telescopes may only receive signals in a
relatively narrow band of wavelengths.
10.8 ARE WE ALONE IN SPACE?
QUESTIONS
1 Radio telescopes are used to search for signals from
extraterrestrial civilisations.
2 It is possible that bacteria are more likely to be found
in other parts of the Universe because they are more
capable of surviving in harsh or extreme
climates/conditions than more complex multicellular
organisms.
3 Benefits from the SETI program include the use of
the SETI algorithms for medical imagining to
improve resolution, digital signal processing for use
in limited bandwidth communication such as the
Internet, detecting and identifying radio frequency
interference easily.
10.9 CHAPTER REVIEW
USING SCIENTIFIC LANGUAGE
1 a Corona. b Fusion.
e Radiotelescopes.
c Pulsar.
d Spectral type.
CHECK YOUR KNOWLEDGE
10.7 LOOKING AT THE STARS
QUESTIONS
APPLY YOUR SKILLS
1 Radio telescopes receive radio waves (or
microwaves) which have a low frequency and are not
absorbed by the Earth’s atmosphere.
2 A refracting telescope makes use of a lens (objective
lens) to converge light rays, and an eyepiece lens to
enable the eye to see the image. A reflecting telescope
(such as the Newtonian or Cassegrain) uses a
parabolic mirror and either a plane mirror or another
curved mirror to direct light to the eyepiece lens. A
refractor uses a lens to collect light and a reflector
uses a mirror.
3 More light can be detected at greater resolution by a
reflecting telescope since it is easier to manufacture
mirrors with very large but precise diameters than to
make very large lenses.
1 a 11 years
b Sunspots are associated with magnetic storms,
which cause interference to radio
communications. Dark spots and high temperature
flares may be evident.
2 Black objects absorb radiation much more efficiently
than light-coloured or shiny objects.
Heinemann Interactive Science 4
Answers to textbook questions  23
CHALLENGE YOURSELF
1
b About 93 million suns
c About 35 million suns
d About 23 days
2 a About 123 million suns
Heinemann Interactive Science 4
Answers to textbook questions  24