SAMPLE PAGES FROM UNIT K
Heinemann Science Scheme
Teacher Resource Pack 2
ISBN: 0 435 58245 3
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This sample contains most of Unit K from Heinemann Science Scheme
Teacher Resource Pack 2 in a PDF format. Because this advance
material has not yet been through all checking stages, it may still contain
minor errors. The following pages are not included in this sample
material but will be in the Pack: test-yourself answers; keywords lists;
glossary lists and teacher notes and answers.
© S Mitchell, 2002, The Heinemann Science Scheme
This material may be freely copied for institutional use prior to the publication of the pack from which it is taken.
However, this material is copyright and under no circumstances may copies be offered for sale.
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Scheme of work
3
5
Teacher and technician notes
6
15
Activities
16
29
Homework
30
34
Specials
35
40
Extension
41
43
Test Yourself
44
46
End of unit test
47
50
Mark scheme
51
52
Student record sheet
53
53
Book
spread
K1
How does light
travel?
Learning objectives
(from QCA Scheme of Work)
Pupils should learn:
l
l
l
l
l
K2
Materials and
light
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C
K3
How do we see
things?
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S Mitchell, 2002, The Heinemann Science Scheme
l
Teaching
activities
that light travels from a source
that light travels at a very high
speed, much faster than sound
to interpret evidence and draw
conclusions from it
that light travels in a straight
line
that the path of light can be
represented by rays
K1
How does light
travel?
(teacher led ± no
student activity
sheet)
that materials may be
transparent, translucent or
opaque
to use ICT to make
measurements
that light may be absorbed,
transmitted or reflected when it
hits an object
K2a Core:
The effect of light
on materials (1)
K2b Core:
The effect of light
on materials (2)
K2b Extension:
The effect of light
on materials (2)
that we see non-luminous
objects because light is reflected
from them and enters our eyes
to represent the path of light by
rays
K3 Help:
How we see things
Learning outcomes
Homework
resources
Specials
recognise that light is all around
state that light travels much
faster than sound
describe evidence to support the
idea that light travels in a
straight line
represent simply the path of
light as rays
K1
How does light
travel?
K1
How does light
travel?
use words precisely when
describing the effects of
materials, eg transparent,
translucent, opaque, reflect,
absorb
use a light sensor to make
comparisons
explain that some light may be
absorbed when it hits an object
K2
Materials and
light
K2
Materials and
light
explain how non-luminous
objects are seen, using words,
eg `because light is reflected from
them and enters our eyes', and
ray diagrams
K3
How do we see
things?
K3
How do we see
things?
(from QCA Scheme of Work)
Pupils:
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l
l
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l
l
l
l
(learning support)
Extension
resources
K2
Bar codes
1
2
C
S Mitchell, 2002, The Heinemann Science Scheme
Book
spread
K4
How does light
reflect?
Learning objectives
(from QCA Scheme of Work)
Pupils should learn:
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l
l
l
l
l
l
that light is reflected from plane
surfaces in a predictable way
to make accurate measurements
to represent data graphically
and draw a line of best fit
to draw a conclusion from data
and to say whether it matches
their prediction
that when light is reflected from
plane surfaces an image is
formed
to make and test predictions
about reflections
to make and test predictions
about the number of images
formed in paired mirrors
Teaching
activities
K4a Core:
Reflection of light
from a plane
mirror
K4b Core:
Images in a plane
mirror
K4c Core:
Images in two
mirrors
K4c Extension:
Images in two
mirrors
Learning outcomes
(from QCA Scheme of Work)
Pupils:
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l
l
l
l
l
l
l
make predictions about the way
that light is reflected from plane
surfaces
make and record accurate
measurements of angles of
incidence and reflection with
respect to the normal
represent the data as a line
graph and draw a line of best fit
make a generalisation, eg the light
is reflected from a plane surface at
the same angle at which it hits it
describe the nature of the image
formed in a plane mirror
eg inverted
suggest how such an image is
formed
make and test predictions about
the number of images formed in
mirrors
record findings, describing
patterns in these
Homework
resources
Specials
K4
How does light
reflect?
K4
How does light
reflect?
(learning support)
Extension
resources
Book
spread
K5
Can light be
bent?
Learning objectives
(from QCA Scheme of Work)
Pupils should learn:
l
l
l
l
l
l
that light changes direction at a
boundary between two different
media
to identify patterns in
observations
to apply understanding of
refraction to everyday situations
that white light can be dispersed
to give a range of different
colours
why the spectrum has seven
colours
to use scientific knowledge to
suggest reasons for physical
phenomena
Teaching
activities
K5a Core:
Can light be bent?
K5a Help:
Can light be bent?
K5b
Making and
dividing white light
(teacher led ± no
student activity
sheet)
Learning outcomes
l
l
l
l
l
l
C
S Mitchell, 2002, The Heinemann Science Scheme
K6
How can we
change colour?
l
l
l
l
l
how coloured filters change
white light
to combine knowledge from
different sources to explain how
coloured filters work
how coloured light can be
combined to produce new
colours
how coloured objects appear in
white light and in different
colours of light
to use scientific knowledge and
understanding to explain
observations
K6a Core:
How can we
change colour? (1)
K6b Core:
How can we
change colour? (2)
K6c
How can we
change colour? (3)
(teacher led ± no
student activity
sheet)
Homework
resources
Specials
Extension
resources
make generalisations from their
observations of refraction,
eg that a change of direction
occurs only at an interface; light
bends towards the normal
(inwards) when travelling from a
more dense to a less dense
medium, and vice versa
draw selected angles of incidence
and refraction and use these to
establish generalisations, eg when
the ray travels from air to glass,
the angle of refraction is smaller
than the angle of incidence
draw a ray diagram to explain a
phenomenon of refraction
identify the colours of the
spectrum
describe how white light is
dispersed by a prism to give a
range of different colours
describe how a spectrum can be
recombined to form white light
K5
Can light be
bent?
K5
Can light be
bent?
K5
Fishing
investigate how coloured filters
change white light
suggest how filters affect white
light
investigate how coloured light
can be combined to produce
new colours
investigate how coloured objects
appear in white light and in
different colours of light
identify and explain patterns of
their observations using
appropriate vocabulary,
eg reflect, absorb, transmit
K6
How can we
change colour?
K6
How can we
change colour?
K6
How do we get
colours on a
television
screen?
(from QCA Scheme of Work)
Pupils:
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l
l
l
l
(learning support)
3
How does light travel?
K1
Resources available
Running the activity
No student sheet ± this activity is teacher led.
Several pieces of rubber tubing can be used with
one mounted 60 W lamp.
Links with
A piece of thread through the three holes is
useful to confirm that the light can only be seen
when the holes are aligned (that is, when the
thread is taut).
Book 2
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Sc1
K1
8K page 1
2fgk
Safety
l
230 V mains lamps must be maintained in
suitable holders with careful supervsion to
ensure bulbs are not removed.
l
Warn students that lamps get hot when in
use.
l
The laser should be handled only by the
teacher. Students must be seated in front of
the laser and facing away from it. Students
must be told not to look directly at the
laser.
Activity procedure
Circus of activities
1 Students look at a lamp along a length of
flexible rubber tubing, with the rubber tubing
both straight and curved.
2 Students shine light through three parallel
cards with central holes. They move the cards
around until light can be seen through them.
3 Students use a ray box and slits to produce
Shadows can be linked with eclipses. More able
students could compare areas of umbra and
penumbra for different sources and source±
screen distances.
These activities could all be done as
demonstrations if time is short.
When using the laser, use chalk dust from the
board rubber to show up the light path, for
example by tapping it with a wooden block or
blowing the dust into the beam.
Materials required
For circus (per class or group)
1 lamp; one (or more) lengths of flexible
rubber tubing
2 three pieces of card, approximately 20 cm
square, with a small hole at the centre of
each; lamp (as in 1); length of thread
3 ray box with single and triple slits, if
available; power supply for ray box; sheet of
white paper
4 large light sources, eg mounted 40 W and
60 W household lamps; small light sources,
eg lamps as above enclosed in a box with a
circular aperture of about 2 cm diameter and
smaller holes for ventilation to prevent
overheating; screen about 1 m away from the
sources; objects to place between source and
screen to cast shadows
rays of light.
4 Students look at shadows with large/small
and bright/dim light sources.
Demonstration with laser
5 A laser is set up behind the class, projecting a
spot of light onto a screen at the front.
6 Chalk dust can be used to make the path of
the laser light visible.
For laser (per class)
l laser, eg 1 mW helium±neon laser
l
board rubber
1
C
S Mitchell, 2002, The Heinemann Science Scheme
The effect of light on materials (1)
Resources available
Materials required
Core sheet
The effect of light on
materials (1)
CD-ROM
All resources customisable
Links with
Book 2
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Sc1
K2
8K page 2
2fgk
Safety
l
Warn students that lamps get hot when in use.
l
If water is used, make sure there are no wet
hands or water near the power supply and
plug.
l
Care is needed in the choice of materials
tested, for example that glass samples do not
have sharp edges. Some materials will melt,
burn and produce fumes if they come into
contact with hot lamps.
Activity procedure
1 An object is placed in front of a ray box, on a
sheet of paper. (The paper makes it easier to
see the rays clearly.)
2 By looking at the paper on the opposite side
of the object to the ray box, students decide
whether the material is transparent,
translucent or opaque.
3 This is repeated for each object in turn.
Results are recorded in a table.
Running the activity
Have a variety of objects available that includes
transparent, translucent and opaque materials.
2
C
S Mitchell, 2002, The Heinemann Science Scheme
Per group
l ray box with single slit and low voltage
power supply
l
sheet of A4 plain paper
l
various objects made from different
materials: some transparent (eg glass,
Perspex, clear polythene/cling film); some
translucent (eg frosted glass); some opaque
(eg a book, a card ± most objects are
opaque)
Sample results
With transparent objects, rays of light are
unaffected.
With translucent objects, rays emerge but their
paths are distorted.
With opaque objects, no light emerges.
Answers
1 a Transparent materials allow light to pass
through unaffected (an object can be seen
clearly through them).
b Translucent materials allow light to pass
through but the light is scattered (an
object cannot be seen clearly through
them).
c Opaque materials do not allow light to
pass through (an object cannot be seen at
all through them).
2 Some transparent objects absorb some of the
light so the object may appear less bright.
Coloured glass or filters will change the
colour of the object, but this is discussed in
Unit K6.
K2a
The effect of light on materials (2)
Resources available
K2b
Running the activity
Core sheet
The effect of light on
materials (2)
Extension
sheet
The effect of light on
materials (2)
CD-ROM
All resources customisable
Links with
Book 2
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K2
8K page 2
2fg
Teachers can decide how much processing is
done by computer, but they should ensure that
all students attempting the extension work know
how to calculate the percentages.
Materials required
For core (per group)
l ray box and low voltage power supply
l
light sensor connected to data logger and
computer
l
materials including good reflectors,
transmitters and absorbers of light,
eg mirror, sheet of glass or Perspex, frosted
glass, wood, carpet
30 cm ruler
Safety
l
Warn students that lamps get hot when in
use.
l
l
Make sure there are no wet hands or water
near the power supply and plug.
Additional for extension (per group)
l glass beaker
l
Care is needed in the choice of materials
tested, for example that glass samples do not
have sharp edges.
l
Activity procedure
Core
1 A light sensor reading is taken at a fixed
distance from the ray box with no material
present.
2 An object is placed mid-way between the ray
box and the light sensor and the amount of
light transmitted by the material found.
3 The light sensor is then placed on the same
side of the material as the ray box to obtain
the amount of light reflected by the material.
4 This procedure is repeated for each of the
materials provided.
5 The amount of light absorbed by each of the
materials is calculated by subtraction.
Extension
This extends the original core activity to
materials that are liquids. Students use the
results from the core experiment to calculate the
percentage of light transmitted, reflected and
absorbed by each material.
liquids (eg water, brine, oil)
Answers
Core
1 To act as a control, so that all other results
can be compared with it
2 Polish it so that it is smoother
3 Discussion question. Possible points include:
need to minimise the amount of light
absorbed by the lampshade, unless a subdued
effect is required; shape ± a wide shallow
cone could be made of a reflective material to
increase light intensity downwards.
Extension
1 Results can be compared universally as they
are not dependent on the light sensor used.
2 Air is a perfect transmitter of light/does not
absorb or reflect any light.
3 For example: smooth, shiny surfaces are the
best reflectors of light. Rough surfaces reflect
light as well but in random directions
(diffuse reflection) so a clear image is not seen.
A pane of glass transmits and reflects light,
particularly when clean! Opaque objects do
not transmit light but can reflect and absorb it.
3
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S Mitchell, 2002, The Heinemann Science Scheme
How we see things
K3
Resources available
Running the activity
Help sheet
How we see things
CD-ROM
All resources customisable
Extra questions can be set for further practice
using other objects in the room.
The teacher or students could add extra objects
to the diagram.
Links with
Book 2
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K3
8K page 2
Students could produce their own diagrams on a
range of themes.
Sc1
The sheet could be set as a homework task.
Materials required
Activity procedure
1 Remind students how we see luminous and
Per student
l copy of the help sheet
non-luminous objects. Look at the first two
diagrams on the activity sheet and discuss
them. (Alternatively, the whole sheet can be
set as a self-study exercise.)
l
sharp pencil
l
ruler
Answers
2 Students add rays to the diagram of a room
See diagram.
to show how various objects are seen.
1
2
2
3
3
4
C
S Mitchell, 2002, The Heinemann Science Scheme
Reflection of light from a plane
mirror
Resources available
Core sheet
Reflection of light from a
plane mirror
CD-ROM
All resources customisable
Links with
The laboratory will probably need to be partially
blacked out for this activity.
This activity can be used to reinforce
investigative techniques, particularly analysis and
evaluation skills.
Materials required
Book 2
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K4
8K page 3
2cfgjl
Safety
l
K4a
Students should take care when handling
mirrors; make sure the mirrors have no sharp
edges.
Per group
l
plane mirror in holder
l
ray box with single slit and low voltage
power supply
l
sheet of A4 plain paper
l
protractor
l
sharp pencil
ruler
l
Warn students that lamps get hot when in use.
l
l
Clear walkways of bags or other obstacles
before using any form of blackout.
Sample results
Activity procedure
1 Students shine a ray of light at a plane mirror
at an angle of incidence of 408 and measure
the corresponding angle of reflection.
2 This is repeated for angles of incidence of
208, 608 and 808.
3 Students plot a graph of their results and
look for a pattern.
Running the activity
Sharp pencils and accurate use of a protractor
are essential if good results are to be obtained.
Students often measure angles of incidence and
reflection to the mirror instead of to the normal
to the mirror.
If the activity is carried out carefully, students
should obtain equality within 1 or 28 for
angles of incidence and reflection. This should
then lead to a graph of y 4 x with very little
scatter.
Answers
1 Straight line graph through the origin with
angle of incidence (i ) equal to angle of
reflection (r )
2 Reference to prediction
3 Accuracy can be judged by the amount of
scatter on the graph
4 Any anomalous points should be checked
5 Angle of incidence 4 angle of reflection
5
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S Mitchell, 2002, The Heinemann Science Scheme
Images in a plane mirror
Resources available
Materials required
Core sheet
Images in a plane mirror
CD-ROM
All resources customisable
Links with
Book 2
SoW
K4
8K page 3
Sc1
Safety
l
K4b
Students should take care when handling
mirrors; make sure the mirrors have no sharp
edges.
Activity procedure
1 Students look at the reflections of letters of
the alphabet in a plane mirror as an aid to
understanding lateral inversion. Cards with
various letters and words on are viewed in a
plane mirror.
2 They also consider which letters are
unchanged, leading to ideas about the
symmetry of some letters.
Per group or student
l
plane mirror in holder (or vertical mirror at
home)
l
pieces of paper or card, about 10 cm24 cm
for words and 4 cm square for single letters
l
bold pen (eg marker pen)
Notes on materials preparation
Teachers of lower ability students may prefer to
prepare the cards with words and letters in
advance to ensure uniformity.
Results
TOT reflects as TOT
HAT reflects as TAH
But SUN reflects so that the N and S are
reversed though the U is unchanged:
NUS
This happens because T O A H U are all
symmetrical about a vertical axis, but N and S
are not.
Answers
Running the activity
1 AHIMOTUVWXY
This activity can be carried out individually if
sufficient plane mirrors are available. As a plane
mirror is the only apparatus required, it is
suitable as a homework task.
3 Individual answers
It is a good idea to consider only capital letters
so that consistent answers are obtained
throughout the group.
6
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S Mitchell, 2002, The Heinemann Science Scheme
2 These letters are all symmetrical about a
vertical axis.
Images in two mirrors
Resources available
l
sheet of A4 plain paper
cork or polystyrene mat (to stick pin in if used)
l
protractor
l
Core sheet
Images in two mirrors
Extension sheet
Images in two mirrors
CD-ROM
All resources customisable
Links with
Book 2
SoW
Sc1
K4
8K page 3
2fgk
Safety
l
K4c
Students should take care when handling
mirrors; make sure the mirrors have no sharp
edges.
Activity procedure
Core
1 Students place two plane mirrors at 908 to
each other and place an object, such as an
optical pin, between them.
2 They count the number of images they can see.
3 This is repeated with the mirrors inclined at
1208.
4 They predict the number of images at 608
and then test their prediction.
Sample results
Core
Angle between mirrors
Number of images
90
3
120
2
60
5
Extension
As core plus:
45
7
30
11
Answers
Core
1 The mirrors and their images make a circular
pattern with a pin in each sector. One of
these is the object pin!
2, 3 Answers depend on prediction made. There
will be 5 images.
Extension
1 For example:
Extension
As an alternative to the core activity, this is
extended to other angles and students are helped
to arrive at an equation for calculating the
number of images seen for a given angle.
object
Running the activity
Give students either the core or the extension
sheet.
The mirrors must be vertical and the angle
between them measured precisely if good results
are to be obtained.
Students often include the object when counting
the number of images and so get a value that is
one more than it should be.
Materials required
Core and extension (per group)
l two plane mirrors with holders
l object (eg optical pin)
120°
object
2 See core answer for question 1.
360
11
3 N4
A
4 23
5 An infinite number (angle between
mirrors 4 08; 360/0 4 infinity)
7
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S Mitchell, 2002, The Heinemann Science Scheme
Can light be bent?
K5a
Resources available
Core sheet
Can light be bent?
Help sheet
Can light be bent?
CD-ROM
All resources customisable
Links with
Book 2
SoW
Sc1
K5
8K page 4
2fgj
Students should take care in handling glass
blocks. Make sure the blocks have no sharp
edges. Glass blocks must not be knocked
together as splinters may fly off.
l
Warn students that lamps get hot when in use.
l
Clear walkways of bags or other obstacles
before using any form of blackout.
Activity procedure
Demonstration/Help
Place a metre ruler in a large glass trough of
water to show that it appears bent due to
refraction. (The help sheet gives support for this
demonstration by guiding students through
drawing a diagram of what is happening.)
Core
1 Students use a ray box to trace the path of a
ray of light through a rectangular glass or
Perspex block for angles of incidence of 208
and 358.
2 The procedure is then repeated for
semicircular and triangular blocks if available.
Running the activity
Students often measure angles of incidence to
the block instead of to the normal to the block.
Note that students do not need to measure the
angles of refraction, as Snell's law and refractive
index (sin i/sin r 4 n) are not required at Key
Stage 3.
8
C
The angles of incidence have been chosen to
avoid total internal reflection. If other shapes of
block are used, teachers should choose suitable
angles of incidence to avoid this.
Materials required
Safety
l
The laboratory will probably need to be partially
blacked out for this activity.
S Mitchell, 2002, The Heinemann Science Scheme
Demonstration
l large glass trough, or similar (must be
transparent)
l
metre ruler
Core (per group)
rectangular, semicircular and equilateral
triangular glass or Perspex blocks
l
l
ray box with single slit and low voltage
power supply
l
three sheets of A4 plain paper
l
protractor
l
sharp pencil
l
ruler
Answers
Core
1 A straight line from the point at which it
enters to the point at which it leaves the
block. The ray of light is pulled back towards
the normal by the block.
2 The incident and energent rays are parallel.
3 As for question 1.
4 The ray of light would have changed
direction (refracted) as it entered the
semicircular block as well as when it left it.
This does not happen if the incident ray is
along a radius so strikes the block at 908 and
hence is not deviated. (A tangent and radius
to a circle are perpendicular.)
5 It would follow the same path through the
block as the original ray, but in the opposite
direction.
Making and dividing white light
K5b
3 Add a second similar prism, inverted with
Resources available
respect to the first, as shown below.
No student sheet ± this activity is teacher led.
white
Links with
Book 2
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K5
8K page 4
light
white
Sc1
light
4 Show that the spectrum disappears from the
screen and white light is seen.
Safety
l
l
Take care in handling prisms. Make sure
the prisms have no sharp edges. Prisms
must not be knocked together as splinters
may fly off.
Lamps get hot when in use.
Activity procedure
1 Use a ray box with a single slit to shine a ray
of white light at one side of an equilateral
triangular glass prism.
screen
red
white
violet
light
I
V
R
O
Y
G
B
equilateral
triangular
prism
Running the activity
Use the largest equilateral triangular prisms
available.
Emphasise that dispersion occurs as light enters
the prism. The spectrum is spread out further by
refraction as it leaves the prism.
The teacher can mention a mnemonic for
remembering the order of the colours,
eg. Richard of York gave battle in vain ± red,
orange, yellow, green, blue, indigo, violet.
Indigo is difficult to distinguish. It is thought
that Newton included it because of the
mysticism associated with the number seven at
that time.
Materials required
l
ray box with single slit and low voltage
power supply
l
two equilateral triangular glass prisms (the
largest available)
l
white screen
2 Place a white screen as shown to display the
spectrum of white light.
9
C
S Mitchell, 2002, The Heinemann Science Scheme
How can we change colour?
Resources available
Core sheets
CD-ROM
Materials required
K6a How can we change
colour? (1)
K6b How can we change
colour? (2)
All resources customisable
Links with
Book 2
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K6
8K page 5
2fgijk
Safety
l
K6a, b, c
See notes for Activity K5b (page 000).
Activity procedure
K6a How can we change colour? (1)
1 Students see the effect of placing red, blue and
green filters, in turn, in front of a ray box.
2 They then use an equilateral prism to
produce a white light spectrum and see the
effect of each of the filters on the appearance
of this spectrum.
K6b How can we change colour? (2)
Students combine the coloured filters used in
Activity K6a, first in pairs and then all three
together, to find out about primary and
secondary colours.
K6c How can we change colour? (3)
This is a teacher demonstration. Place coloured
mains lamps or ray boxes with coloured filters as
before on the bench. Put various coloured objects
in the path of the light and observe their apparent
colour. (The objects will need to be small,
particularly if a ray box is used as the light source.)
Activities K6a and K6b (per group)
l ray box with single slit and low voltage
power supply (one for K6a, three for K6b)
l
red, blue and green filters for the ray box
l
sheet of A3 plain paper
l
equilateral triangular glass prisms (K6a only)
Activity K6c (per class)
l coloured mains lamps or ray boxes with
coloured filters (red, blue and green)
l
objects of different colours
All activities (optional)
l three slide projectors and slide coloured
filters (red, blue and green)
l
projector screen
Sample results
Activity K6a
red filter
red light (R); blue filter
blue
light (B); green filter
green light (G)
Activity K6b
Colours of lights
Colour in overlap
red ` blue
magenta (M)
blue ` green
cyan (C)
red ` green
yellow (Y)
red ` blue ` green
white (W)
Answers
Activity K6a
1, 2, 4, 5 Individual answers.
Students can then be asked to explain why, for
instance, a red object looks black in blue light.
3 Filters absorb all the colours in white light
except their own, eg a red filter transmits
only red light.
Running the activities
6 It is absorbed by the filters.
One or all of the activities can be done as a
demonstration. Three projectors and slide
coloured filters can be used to project the
primary colours onto a screen. The projectors
can be angled to overlap the areas of colour.
7 See Activity K5b.
It may be necessary to partially black out the
laboratory for these activities.
10
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S Mitchell, 2002, The Heinemann Science Scheme
Activity K6b
1 They cannot be made from other colours.
2 They are made by combining two primary
colours (see results table).
3 White: M ` C ` Y42(R ` B ` G)
The effect of light on materials (1)
K2a
Core
Aim
To find out whether various materials are transparent, translucent or opaque.
Equipment
l ray box with single slit and power supply
l plain paper
l objects made of different materials
Ray box lamps get very hot.
What to do
1 Draw a table with five columns like the one below to
record your results.
2
Place the object in front of the ray box, on a sheet of paper.
paper
look at the
paper here
ray box
with
single slit
object
3
Look at the paper behind the object.
4
Decide whether the material is transparent, translucent
or opaque.
5
Fill in your results table by ticking the correct box.
6
Repeat for all the other objects.
Results
Name of object
Material
Transparent
Questions
1 What do you notice about materials
that are:
a transparent?
b translucent?
c opaque?
Translucent
Opaque
2 Think again about the transparent
objects you tested. Did the ray of light
always look exactly the same as when
the object was not there?
Can you suggest a reason for any
differences?
1
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S Mitchell, 2002, The Heinemann Science Scheme
The effect of light on materials (2)
K2b
Core
Aim
To see how much light is transmitted and reflected by
various materials.
Equipment
l ray box with single slit and power supply
l light sensor connected to data logger and computer
Ray box lamps get very hot.
l
l
various materials
ruler
What to do
1 Draw a table with four columns
like the one below to record your
results.
2
3
Place the light sensor a fixed
distance (say 10 cm) from the ray
box. Take a reading.
Put a sample of a material midway between the ray box and the
light sensor. Take a reading of the
amount of light transmitted by
the material.
to data
logger and
computer
ray box
with
single slit
4
Put the light sensor on the same
side of the material as the ray
box. Take a reading of the
amount of light reflected by the
material.
5
Repeat steps 2 and 3 for each of
the other materials provided.
6
Record the results in your table.
7
Calculate the amount of light absorbed
by each of the materials.
light
sensor
object
ray box with
single slit
to data
logger and
computer
light
sensor
Results
Light meter readings (lux)
Material
Transmitted
none (control)
Reflected
Absorbed
0
0
Questions
1 Why did you take a reading with no material present?
2 How could you increase the amount of light reflected by a particular material?
3 How could your results be used in the design of a lampshade?
2
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S Mitchell, 2002, The Heinemann Science Scheme
object
The effect of light on materials (2)
K2b
Extension
Aim
To calculate the percentage of light transmitted, reflected and absorbed by various
materials, including liquids.
Equipment
l ray box with single slit and power supply
l light sensor connected to data logger and
computer
l
l
l
beaker
water and other liquids if available
ruler
What to do
1 Draw a table with four columns like the one in the
core activity to record your results. You may be able to
add more rows to your previous table.
2
Carry out the same procedure as in the core activity,
using a glass beaker as the material.
3
Repeat the procedure with water in the beaker.
4
Use your results to find the amount of light
transmitted, reflected and absorbed by the water.
5
Repeat for other liquids, if available.
6
Draw up a new table like the one below.
Ray box lamps get very hot.
Results
Material
Transmitted (%)
Reflected (%)
Absorbed (%)
none (control)
100
0
0
7
Taking your reading for the amount of light
transmitted with no material present as 100%,
calculate the percentage of light transmitted, reflected
and absorbed by each material, using your results from
both the core and extension activities.
Questions
1 What is the advantage of calculating percentages for
the amount of light transmitted, reflected and absorbed
in each case?
2 What have you assumed about the transmission
properties of air?
3 Use your results to make conclusions about the
transmission, reflection and absorption properties of
different materials.
3
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S Mitchell, 2002, The Heinemann Science Scheme
How we see things
Aim
To draw ray diagrams to show how we see luminous and non-luminous objects.
Introduction
We see luminous objects because light travels from them to our eyes.
We see non-luminous objects because light is reflected from them and enters our eyes.
Because light travels in a straight line, we always draw rays with a ruler.
We show the direction in which the light travels by an arrow.
What to do
Look at the picture of a room.
1
Draw a ray or rays to show how the girl sees the light.
2
Draw a ray or rays to show how the girl sees the clock.
3
Add another light to the diagram so that the girl can
read her book more easily. Show how this helps by
drawing more rays on the diagram.
4
The vase on the window ledge casts a shadow. Draw
rays to show how the shadow is formed. Draw the
shadow of the vase.
4
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S Mitchell, 2002, The Heinemann Science Scheme
K3
Help
Reflection of light from a plane
mirror
K4a
Core
Aim
To investigate reflection of light from a plane mirror.
Ray box lamps get very hot.
paper
cid
en
t
ra
y
plane mirror
in
Equipment
l plane mirror in holder
l ray box with single slit and
power supply
l plain paper
l protractor
l ruler
l sharp pencil
normal
ray box with
single slit
Prepare
1 Predict the result you expect to get.
2
Draw a table with two columns to record your results.
Angle of
incidence
(degrees)
What to do
3 Place the plane mirror on the sheet of paper,
towards the top, and mark its position.
Angle of
reflection
(degrees)
40
20
4
Remove the mirror and draw a line at 908 to
its centre point. This is called a normal.
5
Use a protractor to draw a line at 408 to the
normal. This is called the angle of incidence.
6
Replace the mirror and shine a ray of light along
the line you have drawn, as shown in the diagram.
7
Mark the path of the reflected ray with a pencil.
8
Remove the mirror and use a ruler to draw the reflected ray precisely.
9
Use a protractor to measure the angle between the reflected ray and the normal. This
is called the angle of reflection.
10
Repeat steps 3 to 7 for the other angles of incidence shown in the table.
11
Plot a graph of angle of reflection (y-axis) against angle of incidence (x-axis).
60
80
Analyse
1 What pattern have you found in your
results from the graph?
Evaluate
3 How accurate are your results? How
do you know?
2 Was your prediction correct? If not,
why do you think your results were
different?
4 If the equipment is still set up, check
any results that do not fit the pattern.
5 Write a general rule for reflection of
light from a plane surface.
5
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S Mitchell, 2002, The Heinemann Science Scheme
Images in a plane mirror
Aim
To look at images in a plane mirror.
Equipment
l plane mirror in holder
l pieces of card or stiff paper
l pen (a marker pen is useful)
What to do
1 Place the mirror in its holder vertically on the bench in
front of you.
2
Write TOT on a piece of card.
3
Hold the card in front of the mirror. What do you see?
4
Write HAT on a piece of card and hold it in front of
the mirror. What do you see now?
5
Write SUN on a piece of card and hold it in front of
the mirror. What do you see now?
Questions
1 List all the letters of the alphabet that you think will
look exactly the same in the mirror as on the piece of
card. Use the mirror to see if you are correct.
2 What do you notice about these letters?
3 Write your name on a piece of card as you think it will
look in the mirror. Hold the card in front of the
mirror. What do you see?
If you were right, you should see your name written
correctly. Try again if it was not quite right.
6
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S Mitchell, 2002, The Heinemann Science Scheme
K4b
Core
Images in two mirrors
K4c
Core
Aim
To look at images in two mirrors at an angle to each other.
Equipment
l two plane mirrors in holders
l small object (eg pin)
l plain paper
l polystyrene tile or cork mat
(to stick pin in)
l protractor
paper
object pin
What to do
1 Draw a table with two columns like the one below to
record your results.
2
Arrange the mirrors on the paper so that they are at
exactly 908 to each other.
3
Place the pin, or other object, between the mirrors as
shown.
4
Look into the mirrors and count how many images
you can see.
5
Repeat with the mirrors at 1208 to each other.
Results
Angle between mirrors
Number of images
908
1208
1 Do you notice a pattern? If so, explain it in words.
2 Now predict how many images you would expect to
see if the mirrors were at 608 to each other.
6
Use your equipment to set up this arrangement and
count how many images you can see.
7
Add the result to your table.
3 Was your prediction correct? If not, why do you think
your result was different?
7
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S Mitchell, 2002, The Heinemann Science Scheme
Images in two mirrors
K4c
Extension
Aim
To look at images in two mirrors at an angle to each other.
Equipment
l two plane mirrors in holders
l small object (eg pin)
l plain paper
l polystyrene tile or cork mat (to stick pin in)
l protractor
What to do
1 Draw a table with two columns to record your results.
Head the columns `Angle between mirrors' and
`Number of images'.
2
Arrange the mirrors so that they are
at exactly 908 to each other.
3
Place the pin, or other object, between
the mirrors as shown.
4
Look into the mirrors and count how
many images you can see.
5
Repeat with the mirrors at 1208, 608,
458 and 308 to each other.
6
Record your results in the table.
paper
Questions
1 Draw diagrams, one for each arrangement, to show
what you see.
2 Do you notice a pattern? If so, explain it in words.
3 Write a mathematical equation to link the number of
images (N) and the angle between the mirrors (A).
Start the equation N 4
(Hint: Remember there are 3608 in a complete circle.)
4 How many images would you expect to see if the
mirrors were at 158 to each other? (This is hard to do
experimentally but you can try if you have time.)
5 Now place the two mirrors parallel to each other. How
many images can you see?
How does this fit the equation you wrote in question 3?
(Hint: What is the angle between the mirrors now?)
8
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S Mitchell, 2002, The Heinemann Science Scheme
object pin
Can light be bent?
K5a
Core
Aim
To trace the path of a ray of light through a glass or
Perspex block.
Equipment
l glass or Perspex blocks
l ray box with single slit and power supply
l plain paper
l protractor
l sharp pencil
l ruler
Ray box lamps get very hot.
Do not knock glass
blocks together as splinters
may fly off.
What to do
1 Place a rectangular block of glass or Perspex in
the middle of a sheet of plain paper and draw
around it.
2
Remove the block.
3
Draw a normal line at the middle of one of the long
sides of the block.
4
Draw a line at 208 to this normal to mark the path of
your incident ray.
paper
normal
incident
ray
ray box with
single slit
rectangular
glass block
5
Replace the block.
6
Use a ray box and single slit to shine a ray of light
along the path you have marked for the incident ray.
7
Look at the path followed by the ray of light within the
block and after leaving it.
Continued
9
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S Mitchell, 2002, The Heinemann Science Scheme
Can light be bent? continued
8
Mark two dots on the path of the refracted ray with a
pencil. Join the dots with a ruler to show the path of
the refracted ray.
Ray box lamps get very hot.
Do not knock glass
blocks together as splinters
may fly off.
paper
normal
incident
ray
ray box with
single slit
rectangular
glass block
9
Remove the block and draw the path taken by the ray
of light inside the block.
10
Repeat steps 4 to 9 for an angle of incidence of 358.
1 Describe the path of the ray of light inside the block.
2 What do you notice about the incident and emergent
rays in each case?
11
Repeat steps 1 to 10 for a semicircular and a triangular
block if available. (With the semicircular block, the
normal must be drawn at the middle of the diameter.)
3 What do you notice about the path of the ray of light
in each case?
4 With the semicircular block, how would the path of
the ray of light have changed if the incident ray had
not been drawn to the middle of the diameter? Explain
why.
5 What would happen if the ray box was moved and the
ray of light was shone along the path of the refracted
ray?
10
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K5a
Core
S Mitchell, 2002, The Heinemann Science Scheme
Can light be bent?
K5a
Help
Aim
To draw a ray diagram to show how we see a stick in a trough of water.
What to do
1 Draw a trough of water and a stick, AB, placed in it at
an angle as shown. (Your diagram should take up
about half a sheet of A4 paper.)
A
eye
stick
trough of
water
B
2
Draw a normal (perpendicular line), BN, from the
bottom of the stick.
3
Draw an eye at one side of the tank of water as shown.
4
The end B of the stick appears to be at a point P, about
one-third of the way along BN from B. Mark P on
your diagram.
5
The brain thinks the light from B has come from P in a
straight line to the eye. Draw a dotted straight line
from P to the eye.
6
The light has actually changed direction ± been
refracted ± at the surface of the water at X. The light
has travelled from B to X to the eye. Show this path as
a solid line. Mark on it the direction in which light has
travelled from B to the eye.
7
Draw in the apparent position of the stick.
A
normal
N
eye
X
P
B
11
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S Mitchell, 2002, The Heinemann Science Scheme
How can we change colour? (1)
K6a
Core
Aim
To investigate the effect of coloured filters first on white
light, and then on the spectrum of white light produced
by a prism.
Equipment
l ray box with single slit and power supply
l red, blue and green filters to place in front of the
ray lamp
l plain paper
l equilateral triangular glass prisms
Ray box lamps get very hot.
Predict (1)
1 Predict what you expect to see when:
a
b
c
d
a red filter is placed in front of the ray lamp
a blue filter is placed in front of the ray lamp
a green filter is placed in front of the ray lamp
a blue and a green filter are placed together in
front of the ray lamp.
What to do
paper
eye
ray box
coloured
filter
1
Switch on the ray box (without the slit) to give a beam
of white light.
2
Place a red filter in front of the ray lamp. What do you see?
3
Repeat step 2 using blue and green filters in turn.
4
Repeat step 2 using the blue and green filters together.
2 Were your predictions correct?
3 What do the filters do to the white light?
12
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S Mitchell, 2002, The Heinemann Science Scheme
Continued
How can we change colour? (1)
continued
K6a
Core
Predict (2)
4 Predict what you expect to see when:
a a red filter is placed in the white light spectrum
produced by a prism
b a blue filter is placed in the white light spectrum
produced by a prism
c a green filter is placed in the white light spectrum
produced by a prism.
What to do now
red
Ray box lamps get very hot.
Do not knock glass
blocks together as splinters
may fly off.
white
violet
light
ray box
with slit
equilateral
triangular
prism
coloured
filter
5
Use a triangular prism and a ray box with a single slit
to produce a spectrum of white light.
6
Place a red filter in the path of the spectrum. What do
you see?
7
Repeat step 6 using blue and green filters in turn.
5 Were your predictions correct?
6 What happens to the light that does not pass through
the filters?
7 How could you use a second prism to recombine the
colours to make white light again? Try it out.
13
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S Mitchell, 2002, The Heinemann Science Scheme
How can we change colour? (2)
K6b
Core
Aim
To study the effect of combining coloured filters.
Equipment
l three ray boxes with power supply
l red, blue and green filters to place in front of the ray lamps
l plain paper
What to do
1 Draw up a table for your results like
this one.
2
3
Colours of
lights
Place one filter in front of each ray box so
that you produce beams of red, blue and
green light.
Arrange the red and blue lamps on a sheet
of plain paper so that the beams of light
overlap. What colour do you see in the
overlap region?
red filter
red ` blue
blue ` green
red ` green
red ` blue ` green
paper
red light
ray boxes
blue light
blue filter
4
Repeat step 2 for blue and green filters.
5
Repeat step 2 for red and green filters.
6
Repeat step 2 for red, blue and green filters together.
Questions
1 Why are red, blue and green called primary colours?
2 The colours you made in steps 3, 4 and 5 are called
secondary colours. Why?
3 What colour would you expect to see if you combined
all three secondary colours? Explain your answer.
14
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S Mitchell, 2002, The Heinemann Science Scheme
Ray box lamps get very hot.
Colour in
overlap
How does light travel?
K1
1 Light travels 3 2 106 (300 000) kilometres in 1 second.
a How far in kilometres does it travel in 1 hour?
b How far in kilometres does it travel in 1 day?
c How far in kilometres does it travel in 1 year?
Your answer to c is called a light year.
The nearest star (other than the Sun) is 4 light years away from us.
d How far away is it in kilometres?
2 What evidence do we have that light can travel through a vacuum?
3 Name one thing you have seen that would help you to convince a friend that light
travels in straight lines. Write down what you would say and draw a diagram to
help your explanation.
"
........................................................................................
Homework
Materials and light
K2
1 From the list below, select the object or objects that best fit the following descriptions.
mirror
unpainted wooden door
frosted glass window
a opaque
d the best reflector of light
TV screen
painted wall
b transparent
e the best absorber of light
c translucent
2 What is the difference in the way in which light travels through normal glass and
through frosted glass? Draw diagrams to help explain your answer.
3 a What happens to light when it strikes the unpainted
wooden door?
b The door is rubbed down with sandpaper (to make it smoother) and then
painted.
Explain what happens to light when it strikes the
door now.
1
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S Mitchell, 2002, The Heinemann Science Scheme
How do we see things?
K3
1 a Give one example of a luminous object.
b Give one example of a non-luminous object.
c Draw diagrams to show how the eye sees luminous and non-luminous objects.
2 Copy the diagram of a pinhole camera and a tree.
pinhole
a Draw two rays, one from the top and one from the bottom of the tree, to show
how an image of the tree is formed on the screen.
b How would the image change if:
i the hole is made bigger?
ii three more pinholes are added?
iii the pinhole camera is made longer?
"
........................................................................................
Homework
How do we see things?
K3
1 a Give one example of a luminous object.
b Give one example of a non-luminous object.
c Draw diagrams to show how the eye sees luminous and non-luminous objects.
2 Copy the diagram of a pinhole camera and a tree.
pinhole
a Draw two rays, one from the top and one from the bottom of the tree, to show
how an image of the tree is formed on the screen.
b How would the image change if:
i the hole is made bigger?
ii three more pinholes are added?
iii the pinhole camera is made longer?
2
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S Mitchell, 2002, The Heinemann Science Scheme
How does light reflect?
K4
1 Copy the diagram of a plane (flat) mirror.
30°
a Label:
i the normal
ii the incident ray.
b Add the reflected ray and mark the size of the angle
of reflection.
2 a Ambulances have the word AMBULANCE written
in `mirror writing' on the front. Why is this?
b Some letters appear the same as usual even when
reflected. Why is this?
c Which letters are unchanged?
3 Two plane mirrors are placed at 908 to each other.
A candle is put in front of them.
90°
candle
eye
a How many images of the candle are seen?
b Draw a diagram to show what is seen.
c Copy the diagram and draw a ray of light from the
candle to the eye reflecting off both mirrors.
3
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S Mitchell, 2002, The Heinemann Science Scheme
Can light be bent?
K5
1 Copy and complete the following diagrams to show the
path of the ray of light as it passes through the glass
shapes.
2 A triangular prism can be used to produce the
spectrum of white light.
Copy and complete the diagram to show the formation
of the spectrum.
3 A practical investigation
l Place a coin in the bottom of a cup.
l Move your head to one side so that you just cannot
see the coin.
l Without moving your head, pour water into the cup
until you can see the coin. (You may need to get
someone to help you do this.)
eye
Copy the diagram second. Add rays to the second cup
to show how the coin becomes visible.
4
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S Mitchell, 2002, The Heinemann Science Scheme
eye
How can we change colour?
K6
1 Copy and complete this table.
Colour of lights
Result
red ` blue ` green
red ` green
blue ` green
magenta ` green
blue ` yellow
magenta ` cyan ` yellow
2 Kim has a yellow card with red writing on it. When
she looks at it in red light the writing disappears.
Explain why this happens.
3 At an evening football match, one team wears red strip
and the other wears green. When the floodlights are
switched on they give out blue light. Why does this
cause problems for the players as well as the spectators?
green shirt
red shirt
4 The triangle shows how the three primary colours can
be combined.
Copy it and fill in the missing colours.
R
M
R ⫽ red
M ⫽ magenta
B ⫽ blue
B
5
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S Mitchell, 2002, The Heinemann Science Scheme
How does light travel?
K1
Complete these sentences using the words in the box to fill in the gaps.
distance
lamp
medium
1 A desk
shadow
source
straight
vacuum
gives out light.
Something that gives out light is called a
Light travels in
of light.
lines.
2 Light does not need a
to travel through. Light from the
Sun travels through the
of space to reach us. A light
year is the
light travels in one year.
3 When an object blocks light there is a
.
"
........................................................................................
Specials
How does light travel?
K1
Complete these sentences using the words in the box to fill in the gaps.
distance
lamp
medium
1 A desk
shadow
source
straight
vacuum
gives out light.
Something that gives out light is called a
Light travels in
2 Light does not need a
Sun travels through the
year is the
of light.
lines.
to travel through. Light from the
of space to reach us. A light
light travels in one year.
3 When an object blocks light there is a
.
1
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S Mitchell, 2002, The Heinemann Science Scheme
Materials and light
K2
The word search contains 18 words used when describing the effect of light on
materials. Look for the words listed below.
s
e
r
d
s
m
o
o
t
h
t
d
r
y
m
f
j
o
d
a
o
r
s
t
g
r
l
u
n
o
t
n
u
n
u
r
g
c
r
m
a
e
j
e
s
m
h
g
e
v
s
k
a
a
a
n
f
s
f
h
n
w
h
r
u
b
t
t
n
t
s
q
u
a
i
d
s
e
n
s
o
r
t
s
e
p
i
r
n
n
a
q
q
l
d
q
f
e
m
r
a
r
f
c
y
b
r
q
a
i
b
x
r
i
i
r
j
a
j
g
s
e
r
o
s
g
g
t
s
a
e
d
c
x
l
o
f
m
p
i
u
h
m
s
l
n
s
e
f
a
r
l
y
a
n
b
v
t
i
r
t
g
t
j
s
b
e
n
q
t
t
i
e
o
r
u
i
x
l
s
w
c
o
u
a
t
a
g
n
t
r
v
b
v
o
e
t
v
e
e
i
r
h
k
c
a
o
b
l
s
e
t
r
a
n
s
l
u
c
e
n
t
r
s
h
Here are the words:
absorb
light
mirror
rough
shiny
transmission
2
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S Mitchell, 2002, The Heinemann Science Scheme
dark
material
opaque
scatter
smooth
translucent
glass
matt
reflect
sensor
surface
transparent
How do we see things?
K3
1 a Draw a ray to show how light travels from the torch
bulb to the girl's eye.
b Draw a ray to show how the girl sees the book.
2 The phrases A to E describe the words numbered 1 to
5, but they have been put in the wrong places. Draw a
line to match each word with the letter that describes
it.
1 retina
A it focuses light
2 luminous
B it changes size depending on the brightness
3 lens
C it gives out light
4 fuzzy
D the back of the eye
5 pupil
E blurred
3
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S Mitchell, 2002, The Heinemann Science Scheme
How does light reflect?
K4
1 A ray of light is shone at a flat mirror, as shown in the
diagram. It hits the mirror at X.
a Draw a normal (angle at 908) to the mirror at X.
b Use a protractor to measure the angle of incidence,
i, between the ray of light and the normal.
c Draw the position of the reflected ray as accurately
as you can. Mark the size of any angles that you
measure. Add an arrow to show the direction of the
reflected ray.
2 Fill in the missing angles:
z
x
y
40°
20°
x⫽
z⫽
y⫽
3 Write the word POLICE so that it will look correct
when seen in a mirror.
POLICE
4
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S Mitchell, 2002, The Heinemann Science Scheme
Can light be bent?
K5
Solve the clues and write the answers in the answer grid below. If you get all the
answers correct the first vertical column will show you another word connected
with this topic.
Clues
1 A natural light source.
2 A transparent material, similar to glass.
3 Something you do in the science lab to find out how things behave.
4 `Richard of York gave battle in vain.' This rhyme helps you to remember
the
in a rainbow.
5 The shape of a glass prism used to show dispersion of light.
6 This happens to light as it passes from air into water.
7 The direction in which light travels to your eye when you look at the bottom
of a glass.
8 Light refracts when it passes from one
to another.
Answer grid
1
2
3
4
5
6
7
8
5
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S Mitchell, 2002, The Heinemann Science Scheme
How can we change colour?
K6
Complete these sentences using the colours in the box to fill in the gaps. You may use
each colour once, more than once or not at all.
black
blue
cyan
green
magenta
red
white
yellow
1 If we shine white light through a red filter, only
light
comes through. The red filter transmits only
light and
absorbs all the other colours.
2 The primary colours are
,
and
.
3 When the three primary colours are mixed together we get
light.
4 Red and green filters are used together to get
and
5
light.
filters must be used
together to get cyan.
6 A blue ball looks blue because it is reflecting mostly
light.
7 If we look at the blue ball in blue light, it looks
.
8 If we look at the blue ball in green light, it looks
.
9 If we look at a yellow ball in green light, it looks
.
6
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S Mitchell, 2002, The Heinemann Science Scheme
Bar codes
K2
Read about bar codes and then answer the questions that follow.
Most items purchased, from your text book to
a packet of cornflakes, have a bar code on the
outside.
The bar code, or UPC (universal product
code), represents a numbered code for the
article. The UPC symbol printed on a package
has two parts:
l
the machine-readable bar code
l
the human readable 12-digit UPC
number.
The first six digits of the number identify the
manufacturer.
6
39
38
20
00
39
3
3
Bar codes were originally created to help
supermarkets speed up the check-out process
and keep better control of their stock. The
system quickly spread to all other retail
products because it was so successful.
The bar code is a series of dark lines of various
widths. Each bar code is unique to a particular
item. It is read by a bar-code reader which
shines a beam of laser light on the dark lines.
This is explained in more detail opposite.
The next five digits identify the item.
The last digit is called a check digit. This lets
the scanner determine whether it scanned the
number correctly or not.
Each digit in the bar code is represented in
binary code, using only the numbers 0 and 1.
These digits are represented by a `dark line'
and `no line' to produce a bar code that is
unique to a particular item.
At the checkout the bar code is read
optically using a laser. Laser light is intense
and does not spread out. It passes through
the gaps but is stopped by the dark lines on
the bar code, giving a unique signal that
identifies the item. The unique signal from
the laser is passed on in binary code as the
numbers 0 and 1 so that computers can
understand it.
1 Give two advantages of the bar-code system.
2 Why must the number code be changed to binary for
the laser reader to work?
3 Why is laser light used to `read' the bar code?
4 Manufacturers register with a central body that
oversees the bar-code system. Why is registration
necessary? (Think of as many reasons as you can.)
5 Explain the purpose of the check digit.
1
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S Mitchell, 2002, The Heinemann Science Scheme
Fishing
Primitive hunters probably did not know much about
Physics but they knew how to apply ideas of refraction to
spear fish.
If the fisherman aims his spear directly at the point where
he sees the fish, he will miss it.
1 Explain why he will miss the fish.
2 Make a sketch of the drawing and add a normal to the
surface of the water through the fish's eye. Add the
path of a ray of light from the fish's eye to the
fisherman's eye to show how he sees the fish. Mark the
apparent position of the fish.
3 On your sketch, add a spear in the fisherman's hand
pointing in the direction he must aim to catch the fish.
4 Do you think the fish can see the fisherman? Explain
your answer.
2
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S Mitchell, 2002, The Heinemann Science Scheme
K5
How do we get colours on a
television screen?
K6
Read about colour television and then answer the
questions that follow.
When you watch television, you are watching pictures built up by beams of very small negatively
charged particles (electrons). A beam of particles is produced by a gun at the narrow end of the
tube, so called because it sends particles down the tube at very high speed.
groups of 3 dots
(to make red, blue
and green light)
cover the screen
3 guns
producing tiny
particles (electrons)
When a particle strikes a special coating on the back of the screen, a spot of light is given out. In
a colour television set there are three different coatings. When struck by a particle, one gives out
red light, one gives out blue light and one gives out green light. These coatings are arranged in
groups of three dots, one for each colour, all over the screen. (You can see these dots if you look
closely at a television screen when the set is switched off.) There are three guns, each firing
particles at dots of one particular coating on the screen. In this way one gun produces a red
picture, one a green picture and one a blue picture. The pictures overlap so you see the correct
colours on the screen.
1 Why are screen coatings chosen that give out red, blue
and green light?
2 If only the `red' and `green' guns are giving out
particles, what colour is seen on the screen?
3 Jim thinks that red, blue and green particles are given
out by the gun. What would you say to convince him
that he is wrong?
4 Which guns must be firing particles at the screen to
produce the following colours:
a blue?
b white?
c magenta?
d black?
5 It is often said that black is not a colour. Use your
answers to question 4 to suggest why.
3
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S Mitchell, 2002, The Heinemann Science Scheme
Light
Unit K
1 Draw lines to match up the terms about light with the correct meaning.
term
source
shadow
light year
transparent
translucent
opaque
ray diagram
meaning
the distance light travels in a year
letting no light through
transmitting light in an organised way
represents the path of light
where an object blocks light
scattering light as it is transmitted
something that gives off light
2 Complete the sentences by crossing out the wrong words:
a The Sun/Moon gives out light.
b Light can/cannot travel through a vacuum.
c Light travels 300 m/300 million m in one second.
d Light travels in straight lines/curves.
e A shiny metal surface reflects/absorbs most of the light shining on it.
f A carpet reflects/absorbs most of the light shining on it.
3 Choose from the words in the box to fill in the gaps in the sentences. You may use
each word once, more than once or not at all.
bigger
camera
dark
film
Moon
more
non-luminous
retina
scatter
smaller
a Sources of light are
lens
pupil
Sun
less
luminous
reflect
refract
upside down
because they give out light.
b We see
objects by the light they
c We see the planets because they
the
light from
.
d The human eye is rather like a
. Light passes into the eye
through a hole called the
when it is
. This gets
to let in
light.
The image in the eye is formed on the
is
.
. The image
.
Continued
1
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S Mitchell, 2002, The Heinemann Science Scheme
Light continued
Unit K
4 a Label the diagram below using these words.
mirror
normal
incident ray
reflected ray
b Mark the angle of incidence with a letter i.
c Mark the angle of reflection with a letter r.
d What can you say about the sizes of these angles?
5 Two flat mirrors are placed at 458 to
each other.
A candle is placed between them.
How many images of the candle
45°
can be seen?
6 Complete the diagrams to show the path taken by the ray of light.
7 Cross out the incorrect words so that these sentences make sense.
If we shine white light through a blue filter, only red/blue/green light comes
through. The other colours are absorbed/reflected/scattered. Red, blue and green
are the three primary/secondary colours.
If red and blue lights are shone onto a white screen so that the beams of light
overlap, red/magenta/yellow light is seen.
A yellow scarf looks yellow because it reflects red and blue/green light and absorbs
blue/green light.
Continued
2
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S Mitchell, 2002, The Heinemann Science Scheme
Light continued
Unit K
8 Use the clues below to fill in the words to reveal the name of a famous scientist in
the shaded squares.
1
2
3
4
5
6
The line to which angles of incidence and refraction are measured.
The colour that bends most when light is refracted in a prism.
The colour made by mixing the three primary coloured lights.
The colour of light transmitted by red and blue filters together.
The bending of a ray of light when going from one material to another.
The splitting of light into a range of colours.
1
2
3
4
5
6
3
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S Mitchell, 2002, The Heinemann Science Scheme
Light
Unit K
Tier 3±6
1 How do we see objects that are non-luminous?
(1 mark)
2 Mary holds a doll between a bright light and a screen.
screen
a A clear shadow of the doll is seen on the screen.
What does this tell you about the way that light
travels?
(1 mark)
b Copy the diagram and continue the three rays of
light to show how a shadow of the doll is formed on
the screen.
(3 marks)
c When the light is turned on, Mary can see the
shadow and the brightly lit part of the screen
straight away. What does this tell you about the
speed of light?
(1 mark)
3 Sam sees an EXIT sign reflected in a flat mirror.
Which diagram below shows what Sam sees. (1 mark)
EXIT
b
TIXE
c
EXIT
a
d
EXIT
4 The diagram shows a ray of light reflected from a flat
mirror.
50°
incident
ray
normal
reflected
ray
a Calculate the size of the angle of incidence.
(1 mark)
b i What is missing from the ray diagram?
ii What is the size of the angle of reflection?
(2 marks)
Continued
1
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S Mitchell, 2002, The Heinemann Science Scheme
Light continued
Unit K
Tier 3±6
5 The diagrams A, B and C show a ray of light passing
through a rectangular glass block.
A
B
C
a What is the process of bending light like this called?
A Reflection
B Dispersion
C Refraction
D Scattering
(1 mark)
b Which diagram, A, B or C, shows the correct path
of the light?
(1 mark)
6 Sunlight is split up into a spectrum of colours by a
triangular prism, as shown below.
white
X
light
a What name is given to the splitting up of sunlight in
this way?
A Diffraction
B Dispersion
C Differentiation D Division
(1 mark)
b What colour is the light at X?
(1 mark)
c How does the prism split white light up into a
spectrum?
(1 mark)
7 a White light is shone at a green filter.
What colour is the light transmitted by the green
filter?
(1 mark)
b Grass looks green in white light because it reflects
green light and absorbs all the other colours.
i Explain why a blue flower looks blue in white
light.
(1 mark)
ii If you have a bunch of red and blue flowers, which
flowers will look black in blue light?
(1 mark)
8 A school is presenting `Alice in Wonderland'. In one scene
some of the cast dress up as playing cards. Their costumes
are white with the playing card patterns painted on.
The stage is lit by red light. The red nine of hearts and
the red nine of diamonds look red all over.
Explain why the white background looks red. (1 mark)
2
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S Mitchell, 2002, The Heinemann Science Scheme
Light
Unit K
Tier 4±7
1 The diagram shows a ray of light reflected from a flat mirror.
50°
incident
ray
normal
reflected
ray
a Calculate the size of the angle of incidence. (1 mark)
b i What is missing from the ray diagram? (1 mark)
ii What is the size of the angle of reflection?
(1 mark)
2 The diagrams A, B and C show a ray of light passing
through a rectangular glass block.
A
B
C
a What is the process of bending light like this called?
(1 mark)
b Which diagram, A, B or C, shows the correct path
of the light?
(1 mark)
3 Sunlight is split up into a spectrum of colours by a
triangular prism, as shown below.
white
X
light
a What colour is the light at X?
(1 mark)
b How does the prism split white light up into a
spectrum?
(1 mark)
c A green filter is placed in the path of the spectrum.
i What is seen now?
(1 mark)
ii Explain your answer to i.
(1 mark)
d What would you expect to see if a second prism
were arranged next to the first, as shown in the
diagram below? (There is no need to draw the
diagram.)
(1 mark)
white
light
Continued
3
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S Mitchell, 2002, The Heinemann Science Scheme
Light continued
Unit K
Tier 4±7
4 Kim dives into the swimming pool to fetch a brick
from the bottom. She finds that the water is deeper
than it appeared to be from the side of the pool before
she dived in.
brick
a Copy the diagram and draw a ray of light from the
brick to Kim's eye.
(2 marks)
b Explain why the pool appeared shallower before she
dived in. (You may add line(s) to your diagram to
help your explanation.)
(2 marks)
5 A school is presenting `Alice in Wonderland'. In one
scene some of the cast dress up as playing cards. Their
costumes are white with the playing card patterns
painted on.
The stage is lit by red light. The red nine of hearts and
the red nine of diamonds look exactly the same.
a How will they both look?
(1 mark)
b Explain why.
(1 mark)
6 a Explain why a blue flower looks blue in white light.
(1 mark)
b What colour will the blue flower look in green light?
(1 mark)
7 The Sun is about 150 000 000 km from Earth. Light
travels 300 000 km in one second. How long does it
take light to reach us from the Sun?
(2 marks)
4
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S Mitchell, 2002, The Heinemann Science Scheme
Light
Question
Unit K
Tier 3±6
Part
Answer
Mark
Level
By reflection or light is scattered off them
1
5
Light travels in straight lines
1
3
3
4
Very, very fast or almost instantaneous
1
3
TIXE (E reversed but XIT look the same)
1
5
a
408
1
4
bi
ii
Arrows showing the direction of light
408
1
1
5
5
a
C Refraction
1
4
b
B
1
6
a
B Dispersion
1
4
b
Red
1
5
c
The different colours in white light are refracted by
different amounts by the prism
1
6
a
Green
1
5
bi
The blue flower reflects blue light
and absorbs all the other colours
Black
1
5
1
5
a
All red
1
5
b
The white background material looks red as only red
light is present
1
6
1
2
a
b
screen
c
3
4
5
6
7
ii
8
Scores in the range of:
Level
3±5
3
6±10
4
11±13
5
14±20
6
1
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S Mitchell, 2002, The Heinemann Science Scheme
Light
Unit K
Tier 4±7
Question
Part
Answer
Mark
Level
1
a
408
1
4
bi
ii
Arrows showing the direction of light
408
1
1
5
5
a
Refraction
1
4
b
B
1
5
a
Red
1
5
b
The different colours in white light are refracted by
different amounts by the prism so come out in
different places
1
6
ci
ii
Green part of the spectrum only
Only green light can pass through the filter, all the
other colours are absorbed
1
1
5
5
d
One from:
White light
Parallel to the incident ray
1
6
a
Diagram shows a straight line from brick to water surface
refracted away from the normal to Kim's eye
1
1
5
5
b
Kim's brain thinks that light travels in a straight line
so thinks the brick is nearer the surface or ignores
refraction at the surface (refracted ray continued back
to show position of image)
1
1
6
6
a
All red
1
5
b
Red hearts and diamonds will reflect red light and so will
the white background material as only red light is present
1
6
a
The blue flower reflects blue light and absorbs all the
other colours
1
5
b
Black
1
6
Time 4 distance/speed 4 150 000 000/300 000 4 500 s
or 8.3 minutes (one mark for correct equation and correct
substitution but incorrect calculation; one mark for correct
equation and incorrect substitution but correct calculation;
two marks for correct answer with no working shown)
2
7
2
3
4
5
6
7
Scores in the range of:
Level
4±7
4
8±11
5
12±14
6
15±20
7
2
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S Mitchell, 2002, The Heinemann Science Scheme
Light
Unit K
I can
do this
very
well
I can
do this
quite well
I need to
do more
work on
this
I know what a source of light is
I know how light travels
I can represent the path of light in various circumstances
I can use words precisely to describe what happens to light
when it hits various types of material
I know how to use a light sensor to make comparisons
I know how we see luminous and non-luminous objects
I know how light is reflected from a flat surface
I can measure angles of incidence and reflection accurately
I can represent data as a line graph and draw a line of best fit
I can make and test predictions about the number of images
formed in two inclined mirrors
I can describe the image formed in a plane (flat) mirror
I know how light changes direction at the boundary between
two different media
I can draw ray diagrams to show reflection and refraction
I know the colours of the spectrum formed from white light
I can use a prism to show dispersion
I know how coloured filters change white light
I know how coloured lights can be combined to produce new
colours
I know how coloured objects appear in white light and in
different colours of light
What I enjoyed most in this unit was
The most useful thing I have learned in this unit was
I need to do more work on
1
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S Mitchell, 2002, The Heinemann Science Scheme