Download Chemistry Chapter 5 Review

PHYSICS – LIGHT AND
GEOMETRIC OPTICS
Light and Colour
 White light is actually composed of a combination of
many colours - all the colours of the rainbow.
 If a second prism is added the colours can be
recombined to produce white light. This proves that
white light is made up of multiple colours
The Electromagnetic Spectrum
Additive Colour Theory of
Light
 These three colours of light are known as
primary colours.
Additive Colour Theory of
Light
 If you mix correct amounts of all
three primary colours of light, you
will make white light. If you mix only
two of the primary colours together,
you will make a secondary colour.
 The secondary colours of light for
red, green, and blue are magenta,
yellow, and cyan.
Subtractive Colour Theory of
Light
When a light wave strikes an object
 Some wavelengths of light reflect, which
means that they bounce off the object.
 Other wavelengths are absorbed by the
object.
 The colour you see when you look at an
object depends on the wavelengths that are
reflected
Subtractive Colour Theory of
Light
 The primary and secondary colours of light
for the subtractive theory are opposite to the
colours of the additive theory
 Cyan, magenta, and yellow are the primary
subtractive colours, while red, green, and
blue are the secondary subtractive colours.
Producing Visible Light
 The most important natural source of light on
Earth is the Sun. There are, however, other
natural sources of light, such as light from
other stars, fire, and lightning. Light is also
produced by other methods
Bioluminescence
 The ability of a plant or animal to produce
light is called
 90 percent of all sea creatures are
bioluminescent
 Some fish produce their own light, while others
have bacteria that carry out the light-producing
chemical reaction for them.
Incandescent Light
 Produced by an object,
such as a metal, that is at a
very high temperature.
 Inside an incandescent light
bulb is a filament
 Electric current flows through
the filament, heating it to an
extremely high temperature.
Fluorescent Light
 Light emitted by substances when they are
exposed to electromagnetic radiation.
 A fluorescent light bulb is a glass tube filled
with a small amount of a gas such as mercury
vapour. The inside of the bulb is coated with a
white powder called a phosphor.
Phosphorescent Light
 In fluorescent lights, the phosphor emits light
only while it is exposed to ultraviolet
radiation.
 Some substances have the ability to store
energy from radiation.
Chemiluminescence
 Light produced from a chemical reaction
without a rise in temperature.
 All forms of bioluminescence are special
kinds of chemiluminescence.
 Example: Glow sticks
Triboluminescence
 Producing light from friction
 Some crystals can be made to glow simply by
rubbing them together or crushing them.
Electric Discharge
 The process of producing light by passing
an electric current through a gas
 Example: Neon lights, Lightning, Carbon arcs,
HIDs
Light-Emitting Diode (LED)
 The process of transforming electrical energy
directly into light energy is called
electroluminescence.
 A light-emitting diode (LED) is an
electroluminescent light source made out
of a material called a semiconductor.
Light and Matter
 Ray diagrams are used to describe what
happens when light strikes an object.
 Light travels in straight lines until it
strikes something.
 Material have different properties which
affects what happens when light strikes
them
A ray diagram demonstrating
the law of reflection
 Normal – Dashed line drawn perpendicular
to the mirror at point of reflection.
 Incident Ray – The Incoming Ray of light
 Reflected Ray – The outgoing Ray of light
Law of Reflection
 When light reflects off a surface, the angle of
incidence is always equal to the angle of
reflection.
Plane Mirror drawings
 Images are always drawn in dotted lines
 the point at which the extended reflected
rays converge (come together) behind the
mirror indicates the size and distance of the
object
Drawing a Concave Mirror Ray
Diagram
1. Use an upright arrow to represent the
object
2. Show real rays as solid lines.
3. Use dashed lines to present virtual rays,
which are rays that only appear to exist
behind the mirror.
Images formed by Concave
Mirrors
STEP
12
STEP
- Image STEP
in front
of F
3
 S = Larger
A = UprightL = Behind Mirror
Concave Mirror – Image
behind
C
STEP 1
STEP
STEP23
S. Smaller A.
than object Inverted
L. In front T. Real
of mirror
Summary of Images in a Concave
Mirror
1.
Drawing a Convex Mirror Ray
Diagram
Draw a line from the top of the object straight
Steps
across (parallel to the principle axis) to the mirror.
Then draw a dotted line from there to the focal
point. This line is also drawn as a solid line on the
outside of mirror as it moves away from the
mirror surface.
2. Draw a line from the top of the object to the
center of curvature. Once the line reaches the
mirror it becomes dotted.
3. Draw a line from the top of the object to the
vertex. The reflected ray will leave the mirror at
Images formed by Convex
Mirrors
STEP 1
STEP
STEP23
S = Smaller
A = Upright
L = Behind Mirror
T = Virtual
Refraction
 The bending of light rays as they pass
between two different media is called
refraction
 Refraction is used in designing and building
lenses
 The bending of light is due to different
media slowing light down by different
amounts. The more light slows down the
more it is refracted.
The Index of Refraction
 The amount by which a transparent medium
decreases the speed of light is indicated by a
number called the index of refraction, also
called the refractive index.
 The larger the refractive index, the more
the medium decreases the speed of light.
The Index of Refraction
 Since units cancel, a refractive index value
does not have any units.
Index of refraction of Material = Speed of light in vacuum
Speed of light in medium
OR
n=c
v
Dispersion
 The refraction of white light into separate
wavelengths, or colours.
 A diamond can appear completely colourless
and yet glitter in all colours of the rainbow
because the amount of refraction is different
for each colour.
Snell’s Law
 Snell’s law is a formula that uses values for
the index of refraction to calculate the new
angle that a ray will take as a beam of light
strikes the interface between two media.
Snell’s Law
 If you call the indices of refraction of the two
media n1 and n2 and call the angles of
incidence and the angle of refraction θ1 and
θ2, then the formula for Snell’s law is:
 n1sinθ1 = n2sinθ2
Total Internal Reflection
 In total internal reflection, light reflects
completely off the inside wall of a denser
medium (higher index of refraction) rather
than passing through the wall into a less
dense medium (lower index of refraction).
Mirages
 Since the light rays pass through layers of air
with progressively lower indices of refraction,
eventually the light is totally internally
reflected.
Concave Lenses
 A diverging lens is sometimes
called a concave lens because
it is thinner in the centre than
at the edges.
 As parallel light rays pass
through a concave lens, they
are refracted away from the
principal axis.
 The light rays diverge and they
will never meet on the other
side of the lens.
Drawing a Concave Lens Ray
Diagram
 Any two of the following rays may be used to
locate the image:
1. Draw a ray parallel to the principal axis that
is refracted through the principal focus (F).
2. Draw a ray that passes through the
secondary principal focus (F') and refracts
parallel to the principal axis.
3. A ray that passes through the optical center
goes straight through, without bending.
Only two of these lines are needed to find the
Drawing a Concave Lens Ray
Diagram
2F
S: Smaller
F’’
F
A: Upright
2F’
L: In front of F T: Virtual
Convex Lenses
 A converging lens is also called a
convex lens because it is thicker
at the centre than at the edges.
 As parallel light rays travel
through a convex lens, they are
refracted toward the principal
axis.
 This causes the rays to move
toward each other. The light rays
cross at the focal point of the
Drawing a Convex Lens Ray
Diagram
1. Any ray that is parallel to the principal axis is
refracted through the principal focus (F).
2. A ray that passes through the secondary
principal focus (F') is refracted parallel to the
principal axis.
3. A ray that passes through the optical center
goes straight through, without bending
As with converging mirrors, only two rays are
required to locate an image. The third one
Object between 2F’ and F’
2F’
S: Larger
F’
A: Inverted
F
L: Behind 2F
2F
T: Real
Convex Lenses
Thin Lens Equation
 The distance of the object from the lens, do,
the distance of the image from the lens, di,
and the focal length of a lens, f , can all be
related using the thin lens equation. Given
any two of these quantities, you can use the
thin lens equation to solve for the third:
1=1+1
ƒ do di
Human Vision
 The outer surface of your eye where light enters is
made of a transparent layer of tissue called the
cornea.
 Light can pass right through the cornea yet it is
tough enough to protect the inner eye.
Far-Sightedness
 The eye cannot make the lens thick enough to
refract diverging light rays from nearby objects
correctly on the retina.
 Instead, the image falls into focus behind the eye,
resulting in a blurry image on the retina.
 A converging lens in front of the eye helps the light
rays form the image correctly on the retina
Near-Sightedness
 Distant objects are refracted so much that the
image forms in front of the retina instead of on it.
 The eye cannot make the lens thin enough,
resulting in a blurry image.
 A diverging lens placed in front of the eye helps
the lights rays form the image correctly on the
retina.
Astigmatism
 A condition where the eye is unable to form a
clear image because of an irregular shape of the
cornea or lens. This causes an image to be
formed on more than one place on the retina,
which results in blurry vision.

Types of Telescopes
There are two main types of telescopes: refracting
telescopes and reflecting telescopes.
.
Types of Telescopes
Refracting Telescopes
 A refracting telescope is similar
in design to a microscope, in
that they both have two lenses,
one on each end of a long tube.
Cameras
 A camera is a lightproof box with a lens at one end
to form a real, inverted image on a light detector
or light-sensitive plate or film.
 For a distant object, the image distance di is equal to
the focal length of the lens. For nearer objects, the
lens must be moved farther from the light detector
so that the image is still focussed.
Lasers
 A laser is an optical device that produces a
form of light in which all the light rays are
almost perfectly parallel, all have the same
wavelength, and all of the wave crests and
troughs are exactly lined up.
CLIMATE
Weather and Climate
Although weather and climate are related, they
are not the same thing.
 Weather - refers specifically to the
environmental conditions that occur at a
particular place at a particular time.
 Temperature, air pressure, cloud cover, and
precipitation.
 The effects of weather are immediate and
obvious.
Weather and Climate
 Climate - is the average weather conditions
that occur in a region over a long period of
time, usually a minimum of 30 years.
 Average monthly temperatures and
precipitation, average wind speed and
direction, and a variety of other data.
 Climate is studied by climatologists
Earth’s Biosphere
Earth may be divided into four spheres
 Biosphere (bio = living, Sphere = ball) ; The
living layer around the planet
 Includes – atmosphere, lithosphere, and
hydrosphere
Earth’s Biosphere
 Atmosphere (atmos = gas) ; The gas layer
around the planet
 Lithosphere (lithos = rock); The rock layer
around the planet
 Hydrosphere (hydro = water); The water
layer around the planet
Atmosphere
Air is the mixture of different gases found in the
Earth’s atmosphere.
 The layer of gas that extends out 300km from the
Earth’s surface.
 Major gasses – Oxygen and Nitrogen
 Trace Gases – Argon, carbon dioxide, helium,
methane, and krypton
Layers in the Atmosphere
Earth’s Biomes
 A biome is a large geographical region with a
defined range of temperature and
precipitation - its climate.
 Each biome is characterized by the plants and
animals that are adapted to that climate.
 The Earth has 11 different terrestrial biomes.
◦ The oceans are the marine biome which about 70
percent of Earth.
Trapping Heat
 Some of the solar radiation heats the
objects in the greenhouse which then heat
the air.
 The warm air cannot escape the glass.
Insolation and the Natural
Greenhouse Effect
 Different areas on Earth receive different
amounts of solar radiation.
 Insolation - the amount of solar radiation
received by a region of Earth’s surface.
 Insolation depends on latitude, which is the
distance of any place on Earth from the
equator, shown on a globe by a series of lines
drawn around it parallel to the equator.
The Natural Greenhouse
Effect
 The absorption of thermal energy by the
atmosphere is known as the natural greenhouse
effect.
 This helps keep the temperature of our planet in the
range that supports life.
 Water vapour, carbon dioxide, nitrous oxide, and
methane are called greenhouse gases, gases that
contribute to the natural greenhouse effect. Since so
much water vapour is present in the atmosphere, it is
the main contributor to the natural greenhouse
The Net Radiation Budget
 Almost all the energy absorbed by Earth’s
atmosphere, lithosphere, and hydrosphere is
eventually radiated back into space as
infrared radiation (heat)
 Less than one percent of the incoming solar
radiation is transformed by photosynthesis
into chemical energy.
Albedo
 The albedo of a surface is the percent of the
incoming solar radiation that it reflects.
 Light-coloured, shiny surfaces like snow, ice, and
sand reflect much more solar radiation, 90%
 Darker, duller surfaces such as open water
(about 10 percent), forests, and soils.
 Albedo varies with the seasons and can affect a
region’s radiation budget because it can affect
the temperature and rate of evaporation in that
Thermal Energy Transfer
 The movement of thermal energy from an
area of high temperature to an area of low
temperature.
 Thermal energy transfer can occur by
radiation, conduction, or convection.
Radiation
 Radiation - the emission of energy as waves.
When radiant energy encounters particles of
matter, it may be reflected or absorbed.
Absorbed energy increases the motion of
particles.
 An increase in kinetic energy increases the
temperature of the matter.
 Any substance at a higher temperature than
its surroundings will emit radiant energy,
usually as infrared radiation. The warmed
matter then transfers some of its thermal
energy to substances at lower temperatures or
Conduction
 Conduction - The transfer of thermal
energy through direct contact between the
particles of a substance, without moving
the particles to a new location. Thermal
energy transfer by conduction usually takes
place in solids. During conduction, particles
with more kinetic energy transfer some of
their energy to neighbouring particles with
lower kinetic energy increases the kinetic
energy of the neighbouring particles.
The Coriolis Effect
 The air currents from the equators and poles
would move directly North and South but since the
Earth is rotating on its axis, the winds are
deflected either toward the right or toward the
left. The Coriolis effect is the deflection of any
object from a straight-line path by the rotation of
Earth. The Coriolis effect causes moving air or wind
to turn right in the northern hemisphere and left in
the southern hemisphere.
Convection
 - The transfer of thermal energy through the
movement of particles from one location to
another. Thermal energy transfer by convection
usually occurs in gases and liquids. During
convection, the movement of the particles forms a
current, which is a flow, from one place to another in
one direction. Liquid water has a high heat capacity
which means that it takes a lot of energy to increase
the temperature of a mass of water. Since Earth’s
surface is over 70 percent water, water has a large
effect on Earth’s climate. Therefore, regions closer to
Global Wind Patterns
Jet Streams
 Local conditions such as the presence of continents
or large bodies of water also affect wind patterns.
 A jet stream is a band of fast-moving air in the
stratosphere. Because of their high altitude, these
winds are not subject to much friction and so are
much faster than winds closer to Earth’s surface.
Thermal Energy Transfer in the
Oceans
Greenhouse Gases
Gas
Carbon Dioxide
CO2
Methane CH4
Nitrous Oxide
N2O
Global Warming
Potential over 100
years
1
Persistence
(Years)
-
25
12
298
114
Greenhouse Gas Concentrations
 The additional greenhouse gas emissions are
causing the anthropogenic greenhouse
effect, which is the enhancement of the
natural greenhouse effect due to human
activities.
Greenhouse Gases
Greenhouse
Sources
Gases
Carbon
- Burning coal, oil,
dioxide CO2
gasoline, and natural gas
- Cement making
Methane CH4 - Production of petroleum
products
- Rice paddies, landfills,
cattle
Nitrous
- Burning coal, oil,
Oxide N2O
gasoline, and natural gas
- Deforestation
- Natural gas
leaks
- Coal mining
- Fertilizer
Increasing Greenhouse Gas
Emissions
Human Activities Contribute to
Climate Change
The Pasterze, Austria's longest
glacier
Portage Glacier
Mt. Hood Oregon
Mt. Hood Oregon
Physical Effects of climate
change
 In Canada’s north, areas of permafrost
(permanently frozen soil) are thawing much
more in the summer than they used to. As a
result, the soil becomes looser.
 Trees that tilt or fall over because of this are
called drunken trees
Drought
 Droughts are most severe when they affect
regions near deserts. Until recently, many of
these regions had seasonal rains that
provided the water needed to grow crops and
keep animals.
Wildfires
 When the weather is hot and dry for a long
time, the trees may become so dry that they
lose their leaves. The probability of wildfires
increases.
 While the frequency of wildfires is low around
the world compared with other natural
disasters such as drought, it is increasing.
Storms
 Changes in the frequency and severity of
storms are one potential effect of the rapid
increase in average global temperature and
the movement of energy throughout the
world
Floods
 When the air temperature warms rapidly in
spring, the snow can melt too quickly for the
rivers and streams to handle the run-off.
 These “seasonal” floods damage homes
and cropland and are becoming more
frequent.
Melting Ice
 In the Arctic Ocean, the
amount of sea ice in the
summer has decreased
substantially. The
average level of the
world’s oceans has
increased by about 20
cm over the past
century. This is caused
by land glaciers melting
Ocean Warming
 As the water warms, it expands, so warmer oceans
mean higher sea levels, loss of coastal land.
 Warmer water absorbs less carbon dioxide (just as cold
pop retains more carbon dioxide than warm pop does),
so it is less effective as a carbon sink.
Ocean Currents
 Oceans act as Earth’s heating and cooling
circulation system. As the temperature of
Arctic water increases, it can lead to more
extreme weather around the planet.
Effects of Climate Change on
Wildlife
 Polar bears normally walk on the
ice to hunt seals, because seals
swim too quickly for the bears to
catch them in open water.
 However, when the seals come up
to a hole in the ice to breathe, the
bears can capture them. Less ice
means poorer hunting, and polar
bears are going hungry.
Range Shifts
 Ticks and other pests are also moving North
as the climate warms.
 Wildflowers are blooming 26 days earlier
now.
Organisms That Benefit from
Climate Change
 Some organisms may find their environments
improved as the climate changes.
 Several species of free-living jellyfish have
increased up to 100 times in many coastal
areas of the oceans.
Study Hard
GOOD LUCK ON YOUR FINAL