Homework Mark Scheme
P1a&P1b Foundation & Higher
OCR GCSE
Science
P1b Keeping homes warm
P1a Heating houses
Foundation
Foundation
1
1
2
3
4
(a) The amount of energy a material can
hold (or formal definition); J/kg/°C
(b) (i) Sand has lower shc, therefore
temperature rise is greater
(ii) Water has higher shc, therefore
holds heat better
(a) The amount of energy required to
boil or melt 1 kg of material; J/kg
(b) Latent heat of alcohol; is taken from
skin
Graph to show horizontal portion,
followed by positive gradient, followed
by flat portion, correct melting and
boiling points shown
(a) Joules
(b) Degree of hotness
(c) (i) Rises
(ii) Rises; from block into water
[2]
[2]
[2]
2
[2]
[2]
3
[4]
[1]
[1]
[1]
[2]
4
Higher
1
2
3
4
5
Melting; ice; lower; fixed; point; steam;
upper; fixed; point
Temperature of body varies e.g. if you
are ill; composition of ice/salt mixture is
not specified
(a) E = mcT; meanings of terms
(b) (i) 5 × 800 × 15; 60 000 J
(ii) 5 × 4200 × 70; 1 470 000 J
(a) E = ml; meanings of terms
(b) (i) 2 × 2 300 000; 4 600 000 J
(ii) 1 × 4200 x 90; 378 000 J; to
vaporise needs 2 300 000 J;
total 2 678 000 J
(a) Ice is melting; inter-molecular
bonds in solid are being broken
(b) Water is being heated; velocity of
molecules is increasing; molecules
are still close together
(c) Intermolecular bonds are broken;
molecules become well separated;
velocity of molecules becomes
much greater
[9]
[2]
[2]
[2]
[2]
[2]
[2]
[4]
[2]
[3]
[2]
[2]
[2]
[1]
[2]
[3]
[1]
[2]
[2]
[1]
[2]
[7]
Higher
1
[3]
(a) (i) Two methods, score 1 each
(ii) Double glazing; curtains
(iii) Polystyrene granules; glass
fibre matting
(iv) Carpets
(b) Loft insulation; since warm air rises,
this is biggest heat loss
(a) Foil 0.5 years; Cavity wall 10 years;
Double glazing 40 years
(b) (i) New payback time is 27 years
(ii) No; Payback time on cavity
wall insulation is far better
(a) (i) Efficiency = 800/1000; this is
0.8
(ii) Through the flue
(b) Flue is directly over fire, hot air
rises
Open fire is expensive to install; and to
operate; also dangerous; portable electric
heater is cheap to install; but expensive
to run; storage heater is more expensive
to install; but running cost is lower
2
3
Heat loss by air movement is called
convection it can take place in the spaces
in cavity walls. Radiation is a process by
which heat is lost from hot surfaces it
can be reduced by making surfaces
shiny. Heat can be wasted through solid
materials like floors this is an example of
conduction. Insulating materials like
glass fibre matting work because they
contain pockets of trapped air. Heat loss
through outside walls can be reduced by
filling the wall cavity with foam. In hot
countries, the outside walls of houses are
often painted white because white walls
do not absorb radiant heat well.
[6]
(a) (i) 2000 × 60 × 60; 7.2 × 106
[2]
(ii) 7.2 × 106 × 0.95; 6.8 × 106
[2]
(b) Any three sensible moves, e.g. draw
curtains; draught proofing
[3]
A heat; B roof; C rises; D insulation;
E glass fibre matting; F polystyrene
beads; G carpets; H air; I conductor;
J payback; K radiation.
[11]
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Homework Mark Scheme
P1c&P1d Foundation & Higher
OCR GCSE
Science
P1c How insulation works
P1d Cooking with waves
Foundation
Foundation
1
1
2
(a) Reflects radiant heat
[1]
(b) Traps air against floor.
[1]
(c) Heat loss/draughts through windows
reduced
[1]
(d) Cold part of convection current;
produced by radiator
[2]
(a) Sensible scale for axes; axes correct
way around; points correctly plotted
score 2 marks per line; smooth
curves score 1 each
[10]
(b) Can 3; rate of temperature fall is
greatest
[2]
(c) Traps pockets of air
[1]
(d) Prevents heat loss; by convection
[2]
2
Higher
1
2
(a) Sensible scale for axes; axes correct
way around; correct plotting scores
2 marks per line; smooth curves
score 1 each
(b) Matt black can; rate of temperature
rise is greatest
(c) 100 °C; boiling point of water
(d) Matt black can; this has higher
temperature and better radiating
surface
(e) Temperature of heater is higher
(a) High temp at one end of rod excites
atoms; increased KE is passed to
neighbouring atoms, and so along
the rod; reference to excitation of
electrons earns bonus mark
(b) (i) Simple experiment described
for liquid; similarly for gas
(ii) Gas/liquid expands when
heated; this increases its
volume; thus lowering its
density; the less dense material
rises
[8]
[2]
[2]
Infrared
Black; best radiator of heat
Glass fibre matting
Prevents heat loss
By conduction
To ensure oven is up to temperature;
to radiate sufficient heat
(g) (i) 20 minutes
(ii) Oven temperature
[1]
[2]
[1]
[1]
[1]
(a) See student sheet
(b) See student sheet
(c) Allow steam to escape, otherwise
bag will burst
(d) Reflect microwaves
(e) Ensures even cooking
(f) Twice the time in (b)
(g) Water
(h) Allow heat to penetrate; by
conduction/convection
[1]
[1]
[2]
[1]
[1]
[2]
[1]
[1]
[1]
[1]
[2]
Higher
1
[3]
[1]
[3]
[2]
2
[4]
(a)
(b)
(c)
(d)
(e)
(f)
(a) Polarity of molecule
(b) A timer is used; to turn magnetron
on and off
(c) To ensure even cooking
(d) Wire mesh in door
(e) (i) See student sheet – value is
interpolated
(ii) Twice the above time
(iii) Allow steam to escape/prevent
bag exploding
(iv) Allow heat to penetrate beyond
surface layer; by conduction or
convection
(a) She is hidden from the transmitter
by buildings
(b) Provide an additional transmitter
(c) Microwaves
(d) Affect brain cells
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Homework Mark Scheme
P1e&P1f Foundation & Higher
OCR GCSE
Science
P1e Infrared signals
P1f Wireless signals
Foundation
Foundation
1
2
(a) Infrared
(b) Control is inside car; hold it out of
window
(c) (i) Yes; oscilloscope gives a trace
(ii) Digital
(iii) No; it would give the incorrect
digital code
(a) Analogue is continuously variable;
digital is on/off
(b) Little energy loss during
transmission
(c) To boost signals; to overcome signal
loss
(d) Total internal reflection
(e) A series of short beeps
[1]
1
[2]
[2]
[1]
2
[2]
[2]
3
[1]
[2]
[1]
[1]
Higher
1
2
(a) Infrared
(b) A book is blocking the signal
(c) (i) An on/off signal
(ii) Less interference
(iii) Correct diagram
(iv) Both have different digital
codes
(a) Suitably labelled diagram
(b) (i) Less than critical angle;
refraction is towards normal;
angle y is less than angle x
(ii) Greater than critical angle; TIR
takes place
[1]
[1]
[1]
[1]
[1]
4
[2]
(6)
[2]
[1]
[1]
[1]
[3]
[5]
Higher
1
[1]
[1]
[3]
A electromagnetic; B communication;
C twenty four; D cables; E portable;
F convenient
(a) Walls etc. are in the way;
interference from electrical
equipment
(b) (i) Change to a different channel
(ii) Wavelength/frequency is
changed
(a) Increases the ‘horizon’ of the
transmitter
(b) Both reflection, and refraction of
waves, take place in the atmosphere
See textbook p168. Each correct feature
scores one mark plus additional mark for
quality of diagram
2
(a) To focus waves onto receiving aerial
(b) Wave has to travel further; both are
electromagnetic waves; both have
same speed; satellite signal therefore
takes longer
(c) Orbital period matches speed of
rotation of Earth; satellite is
therefore always over the same spot
(d) Avoids energy loss; due to
diffraction at edge of dish
(a) Suitable labelled diagram; mention
of different densities of air
(b) Suitable labelled diagram; mention
of charged layer
3 of 16
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[4]
[2]
[2]
[2]
[2]
Homework Mark Scheme
P1g&P1h Foundation & Higher
OCR GCSE
Science
P1h Stable Earth
P1g Light
Foundation
Foundation
1
2
1
(a) Vibrations at right angles to
direction of propagation of wave
(b) Standard diagram – features score 1
each – see below.
(c) 20 x 0.5, 10 m
(d) (i) Two named score 1 each
(ii) Speed
(e) Monochromatic; intense; narrow
beam; coherence
(a) Can you come for tea tonight?
(b) Digital; light is on or off
(c) No wires needed
[2]
2
[4]
[2]
[2]
(1)
3
[4]
[5]
[2]
[1]
A Sun; B space; C ultraviolet;
D sunburn; E skin; F cancer; G fair;
H sunblock; I sun; J protection; K factor [11]
(a) Traps the heat from the sun;
greenhouse effect; temperature rises
[3]
(b) Reflect suns rays; Earth less hot
[2]
(c) Reflect heat from Earth; temperature
rises
(2)
(a) Reading down the table:
S waves – side to side movement;
transverse; yes; no; slower
P waves – up and down movement;
longitudinal; yes; yes; faster
[10]
(b) Seismograph
[1]
Higher
Higher
1
1
2
3
4
(a) Sound wave 1.29 m; Radio wave
1500 m; Microwaves, 1010 Hz;
Light 3 × 1015 Hz
(b) Sound; speed is different
(a) At right angles to direction of
propagation
(b) Correct names 1 each
(c) Any three score 1 each
(a) Disc surface has minute pits; laser
light; is reflected; gives digital
signal
(b) All peaks come together
(c) No splitting takes place; light is
monochromatic
This is open to the imagination of the
student but some possibilities are:
banging on walls; flashing the lights on
and off; tying to tension-retaining lines.
Reasonable methods should score 1 each
and an explanation adds a further mark
Electromagnetic
field
+
C
[5]
(2)
[1]
[4]
[3]
2
[4]
[1]
[2]
[2]
(a) P waves; these are faster; and can
travel right through the earth
(b) S waves; these cannot travel through
liquid interior of Earth
(c) P waves are faster; they arrive first
(d) (i) P waves
(ii) This is a longitudinal wave;
caused by push and pull on the
Earth’s crust
(a) Ultraviolet
(b) Ozone
(c) (i) CFCs
(ii) Refrigerants; aerosol
propellants
(d) Penetrative; short wavelength;
disrupts chemical bonds; damages
tissue etc.
(e) Dark skins absorb these rays; in the
upper layers; lower layers protected
C: crest
B: amplitude
B
0
Distance
along
wave
A: wavelength
-
A
D
D: trough
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[3]
Self-assessment quiz: Answers
P1a Foundation and Higher
OCR GCSE
Science
Heating houses
1
Complete the following sentences by writing the appropriate word from this list in the
spaces provided.
temperature
[F]
°C
low temperature
Heat is a form of energy
joules
high temperature
hotness
energy
.It is measured in the units of energy which are called
. Temperature is a measure of hotness
units called °C
. It is measured in
. Heat flow is directed by temperature . Heat
energy flows from objects with high temperature
low temperature
2
joules
to objects with
.
Complete these definitions:
[F/H]
Specific heat capacity is the quantity of heat required to raise the temperature of
one kilogram
of a substance by one degree celsius
quantity of heat energy required to convert one kilogram
from solid
to liquid
to vapour
capacity is J/kg/°C
3
of a substance
at its freezing point. OR the
quantity of heat energy required to convert one kilogram
liquid
Specific latent heat is the
of a substance from
at its boiling point. The unit of specific heat
and of specific latent heat is J/kg
.
Complete this paragraph:
[F/H]
The specific heat capacity of a substance measures how much heat a substance can hold
.
Substances which have a low value of specific heat capacity are generally metals
whereas non-metals
generally have higher values. Water
has the particularly high
value of 4200 J/kg/°C.
4
Complete this paragraph:
[H]
The heat energy gained by an object may be calculated using the formula E = mcT.
In this formula, E represents heat energy
m represents mass of the object
and is measured in joules
and is measured in kilograms
.
.
c represents specific heat capacity and is measured in joules per kilogram per °C .
T represents temperature change
and is measured in °C
.
The heat energy change when a substance changes state may be calculated using the
formula E = ml. In this formula, E represents heat energy
joules
. m represents mass of substance
l represents specific latent heat
and is measured in
and is measured in kilograms
and is measured in joules per kilogram
.
.
5 of 16
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Self-assessment quiz: answers
P1b Foundation and Higher
OCR GCSE
Science
Keeping homes warm
1
Use the following words to complete the paragraph below.
[F]
conductors fibreglass air insulation blocks money energy
If we insulate our homes properly we can save a great deal of money
energy
as the
costs of running the house are reduced. To reduce energy loss we can use
materials which are poor conductors
are fibreglass
and insulator blocks
of heat in house building. Good examples
since these materials trap air
which is a good insulator.
2
Join the following methods of insulation to the place in which they are used to reduce heat loss
in houses.
3
[F]
Method
Where used
Fibreglass
Windows
Double glazing
Cavity walls
Insulating foam
Behind radiators
Reflecting foil
Lofts
Draught proofing
Doors
The payback time for house insulation may be calculated using the formula: Payback
time = installation cost/fuel saving
[F/H]
Explain what is meant by the following.
(a) Payback time The period of time taken for the cost of the improvement to be
met by the savings
(b) Installation cost The cost of installing the improvement
(c) Fuel saving The cost of the fuel which the improvement saves in one year
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Self-assessment quiz: answers
P1c Foundation and Higher
OCR GCSE
Science
How insulation works
1
True or false? Put T or F in the boxes.
[F]
F
Loss of heat from our homes does not matter since energy is cheap.
Air is a poor conductor of heat.
Fibreglass traps pockets of air.
Heat loss by convection can take place in solids.
Movement of particles in liquids and solids causes heat loss by radiation.
Convection is due to infrared rays.
Hot air falls because it is more dense than cold air.
T
T
F
F
F
F
T
Aluminium foil placed behind radiators reduces heat loss by radiation.
2
Complete the following which concerns methods of heat transfer.
[H]
(a) Conduction
solids
This takes place through
particles transferring their
as fibre
glass
and is caused by
kinetic
vibrating
energy to one another. Materials such
can reduce heat loss by this method which is
roof
greater through the
of a house because hot air rises. Metals
are
particularly good conductors of heat because their structure contains electrons
which can move, so making energy transfer easy.
(b) Convection
This takes place in liquids
particles are free to move
and gases
because their
. When the material becomes hot it
expands
, increasing its
volume
density
. The hot material rises
and reducing its
and is replaced by cold
material. We call this movement a convection current. Convection
can take place inside a
cavity
wall unless it is filled with foam or some
similar material.
(c) Radiation
This is caused by infrared
rays and needs no medium
method by which we receive energy through space
Sun
.
Dull black
heat. They are also the best absorbers
. It is the
from the
surfaces are particularly good radiators of
of this type of energy. This is why
houses in hot countries are often painted white
to reduce the effect of
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Self-assessment quiz: answers
P1c Foundation and Higher
Science
radiant heat from the Sun.
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Self-assessment quiz: answers
P1d Foundation and Higher
OCR GCSE
Science
Cooking with waves
1
True or false? Put T or F in the boxes.
[H]
Microwaves and infrared are both part of the electromagnetic spectrum.
Shiny surfaces emit infrared very well.
Microwaves can be used for cooking but we cannot cook using infrared waves.
Microwaves are absorbed by water molecules causing their temperature to rise.
Dull black surfaces absorb infrared well.
Mobile phones use microwaves but there is absolutely no risk of brain damage
from them.
Infrared emission increases as objects become cooler.
2
T
F
F
T
T
F
F
Complete the labels on this diagram of a microwave oven.
[F/H]
outer casing
protects from
wave guide
microwaves
directs waves to food
magnetron
produces
microwaves
food
turntable
ensures even
cooking
3
Complete the following paragraph concerning microwaves and infrared waves.
Microwaves and infrared both transfer
absorbed by
[H]
to materials. Microwaves are
molecules increasing their
but there is insufficient energy to break the
Infrared is absorbed by all particles in the
bonds.
increasing their
. Energy is then transferred into the centre of the food by
and
. Energy loss in microwave transmissions
used for communications is a problem. This is caused by
and
of the waves.
9 of 16
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Self-assessment quiz: answers
P1e Foundation and Higher
OCR GCSE
Science
Infrared Signals
1
Use words from the list to complete the paragraph below.
phones internal
digital total
reflection
videos computers security analogue
automatic
[F]
televisions
burglar
The remote controls which we use for things such as televisions
and automatic
doors use infrared
lights. The signals may be either analogue
variable) or digital
, videos
signals. Because infrared comes from
hot objects it can be used to detect body heat to operate burglar
security
infrared
alarms and
(continuously
(on/off).
Infrared signals can be transmitted along optical fibres. This is possible because of
total
2
internal
reflection
.
Complete the following sentence.
[F/H]
Total internal reflection takes place where two materials, such as glass and air, meet if
the angle of incidence of the beam at the surface exceeds an angle which we call the
.
3
Complete the diagram below which shows a beam of radiation hitting a glass/air
boundary at an angle of incidence which exceeds this value.
air
glass
i r
normal
4
The diagram below shows an optical fibre being used to transmit a beam of light.
Complete the diagram to show how the beam of light reaches the other end of the fibre.
[H]
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OCR GCSE
Self-assessment quiz: answers
P1f Foundation and Higher
Science
Wireless Signals
1
Use the words from the list to complete the paragraph below:
laptop computers, electromagnetic, wiring, refracted, frequency, reflected, mobile
telephones, 24 hours, portable and convenient, interfered, communication
Wireless signals are a type of ___electromagnetic_____________ wave which are
widely used for _communication
. They have the advantage that they are
available ___24 hours_________ a day, need no __wiring
and are
___portable and convenient_________. They have the disadvantage that they are easily
__interfered with by other transmissions of a similar ___frequency_____________ .
Like other radiations, they can be ___reflected_____________ from surfaces and
_____refracted______________ where they travel from one medium to another. But
they are commonly used in radio, __laptop computers______________ and ____mobile
telephones_________ .
2
(a) Draw a sketch to show what is meant by the horizon of a transmitter.
[F/H]
(b) Draw a second sketch to show how the horizon of a transmitter increases when the
height of the mast increases.
refer to page 168 of the foundation student book or page 169 or the higher
textbook
3
Some definitions are given below. For each, give a word which best fits the definition. [H]
(a) The effect which causes bending of radio waves as they pass from one region of the
atmosphere to another.
refraction
(b) The effect which causes loss in signal strength of radio waves if transmission
reflecting dishes are made too small.
diffraction
(c) The effect which bounces radio waves back from the ionosphere to Earth.
reflection
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P1f Foundation and Higher
Science
(d) The effect which takes place when two radio stations of similar frequencies broadcast in the
same area.
interference
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Self-assessment quiz: answers
P1g Foundation and Higher
OCR GCSE
Science
Light
1
[F]
crest
amplitude
trough
wavelength
The diagram shows a transverse wave. Mark on the diagram: (i) the wave crest; (ii) the wave
trough; (iii) the amplitude of the wave; (iv) the wavelength of the wave.
2
Use the words from the following list to complete the paragraph below.
transverse
Morse
speed
communication
water
All electromagnetic waves are transverse
is perpendicular
[F]
perpendicular
waves. The motion of the particles
to the direction of travel of the wave. Waves on water
are also an example of this type of wave. All electromagnetic waves travel at the same
speed
in space. Historically, light was used to increase the speed of
communication
3
but it required the use of a code such as Morse
code.
Write the equation which relates the speed of a wave to its frequency and wavelength.
[H]
speed = frequency × wavelength
4
Radio 4 broadcasts at a wavelength of 1500 m. If the speed of radio waves is
3 × 108 m/s, calculate the frequency of this wave.
200 kHz
5
Complete the following paragraph which refers to lasers.
Lasers produce a very narrow
waves are of the same
[H]
beam of light in which all the
and are in
with
one another. Lasers are used in CD players. A laser beam is shone onto the surface of
the disc from which it is
because it is
.
The surface of the disc carries the information as a series of
which result in the signal being
. This improves the quality of
the sound when it is reproduced.
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Self-assessment quiz: answers
P1h Foundation and Higher
OCR GCSE
Science
Stable Earth
1
True or false? Put T or F in the boxes.
[F]
F
Earthquakes can be detected using an instrument called a shiftmeter.
Ultraviolet rays are harmless to us.
Ultraviolet rays cause sunburn and even skin cancer.
Sun blocks allow us to spend longer periods in the sunshine.
Increasing levels of carbon dioxide in the atmosphere have no effect upon
climate.
The destruction of the rain forests has no effect upon the level of carbon dioxide
in the atmosphere.
2
F
T
T
F
F
Complete the following sentences.
[F/H]
Earthquakes produce shock waves which also travel inside the Earth. These waves are
of two types. P waves are longitudinal
solids
and liquids
waves which travel through both
. Their speed is greater
S waves. S waves are transverse
solids
waves which travel through
but not through liquids
the outer core
than
so they do not travel through
of the Earth’s structure.
Dark skinned people have a lower risk of skin problems due to exposure to the Sun
because more ultraviolet radiation is absorbed in the
less reaches the
lower
outer
layer of the skin so
layers. Sophie has fair skin and finds that she can
only expose herself to the Sun for 10 minutes. If she uses a sun block with a SPF of 10
she should find that she is able to expose herself for
3
100
minutes.
(a) Describe how seismic waves can be used to give evidence for the structure of the
Earth.
[H]
Your answer should refer to the difference in time of travel between S and P
waves. P-waves travel faster than S-waves so will be detected sooner. But P waves
can travel through all layers of the Earth’s structure, whereas S-waves cannot
travel through the outer core.
(b)
Describe how the Earth is protected from the harmful ultraviolet rays from the Sun
and how atmospheric pollution is damaging the upper atmosphere.
[H]
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Self-assessment quiz: answers
P1h Foundation and Higher
Science
Harmful ultraviolet rays are absorbed by the layer of ozone in the upper atmosphere.
This layer is being damaged by a complex series of chemical reactions involving CFCs.
This is creating a hole in the ozone layer through which harmful rays can pass.
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P1h Foundation and Higher
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