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Scheme of work – Cambridge International AS Level Physical Science (8780)
Ph4 PHYSICS
Unit 4: Oscillations and waves
Recommended prior knowledge
Students should be able to describe basic wave behaviour, gained through a study of optics. They should be aware of the basic ideas of reflection and refraction of
light.
Context
Waves and wave theory are an important aspect of any physics course since wave phenomena are present throughout our everyday lives. The course provides an
understanding for those students who will not be studying physics beyond AS level and a basis for further study in physics and physical science courses including
wave-particle duality.
Outline
The quantities by which a wave is specified are considered. Different types of wave are studied. Emphasis is placed on the phenomena of superposition,
interference and diffraction.
Syllabus ref
Learning objectives
Suggested teaching activities
Learning resources
Candidates should be able to
There is a limited supply of past papers
for the 8780 examination, therefore all
examples of examination questions are
taken from Physics 9702 AS papers.
These reflect the type of question that
candidates are likely to meet in the
8780 examinations.
8(c)
8(a) & (b)
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describe what is meant by wave
motion as illustrated by vibration
in ropes, springs and ripple tanks.
describe basic wave behaviour
Discussion: wave as a means of energy transfer by vibrations
no mass motion of the medium (if there is one)
Revision: Link the ideas in 8(c) and (g) to previous knowledge, show
Cambridge International AS Level Physical Science (8780)
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Syllabus ref
8(d)
Learning objectives
Suggested teaching activities
gained through a study of optics
show an understanding of the
basic reflection and refraction in
light
reflection and refraction on the ripple tank
recognise transverse and
longitudinal waves
Experiments with ropes, slinkies and ripple tanks
Discussion:
Transverse waves:
defined in terms of direction of vibration
and of energy transfer
Examples
Longitudinal waves:
defined in terms of direction of vibration
and of energy transfer
Examples
Learning resources
Rope, slinky spring, ripple tank
Transverse: plotting displacement (y-axis) and
distance or time (x-axis)
Longitudinal: mapping undisturbed and
disturbed layers of air –
compressions and rarefactions.
Displacement along direction of
travel plotted on y-axis.
Could also be excess pressure
(y-axis) against distance or time
(x-axis).
Similarity of transverse & longitudinal graphs
8(i)
8(g)
v1 2Y05
analyse and interpret graphical
representations of transverse and
longitudinal waves.
Transverse: plotting displacement (y-axis) and
distance or time (x-axis)
Longitudinal: mapping undisturbed and
disturbed layers of air –
compressions and rarefactions.
Displacement along direction of
travel plotted on y-axis.
show an understanding that
Discussion: wave as a means of energy transfer by vibrations
Cambridge AS Level Physical Science (8780)
Examples:
Oct/Nov 2011, 9702 Paper 23,
question 5(a) &(c)
Oct/Nov 2010 9702 Paper 22,
question 5
2
Syllabus ref
Learning objectives
Suggested teaching activities
Learning resources
Discussion: meaning/ definitions of
(i) frequency f and period T
(ii) displacement x and amplitude A
(iii) wavefront and wavelength λ
(iv) speed
(v) phase difference/angle between two
points on a wave and between two
continuous waves
x/t and x/distance graphs as worked examples
Example:
Oct/Nov 2009, 9702 Paper 21,
question 5(a) & (b)
energy is transferred due to a
progressive wave.
8(e)
show an understanding of and
use the terms displacement,
amplitude, phase difference,
period, frequency, wavelength
and speed.
sine wave generator, loudspeaker,
leads microphone, c.r.o.
ripple tank
deduce, from the definitions of
speed, frequency and
wavelength, the equation
v = fλ.
Derivation of v = fλ
8(h)
recall and use the relationship,
intensity ∝ (amplitude)2.
Revision: a wave as a means of energy transfer
Discussion: what is intensity
define as power incident per unit
area – units W m–2
intensity ∝ (amplitude)2.
Examples:
Oct/Nov 2010 9702 Paper 23
question 5
Oct/Nov 2011 9702 Paper 23
question 5(a)
May/June 2011, 9702 Paper 23,
question 6
Oct/Nov 2009, 9702 Paper 21,
question 5(a) (b)
May/June 2008, 9702 Paper 2,
question 5(a)
8(j)
Determine the frequency of sound
using a c.r.o.
Experiment: determine of frequency of a sound wave
sine wave generator, loudspeaker,
microphone, leads, c.r.o.
8(f)
Worked examples
Examples
May/June 2010, 9702 Paper 23,
question 5
8(k)
v1 2Y05
state that all electromagnetic
Discussion: speed of sound in gases and solids
Cambridge AS Level Physical Science (8780)
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Syllabus ref
Learning objectives
Suggested teaching activities
Learning resources
waves travel with the same speed
in free space and recall the
orders of magnitude of the
wavelengths of the principal
radiations from radio waves to γrays.
speed of e.m. waves in free space
The e.m. spectrum – principal radiations
– wavelengths
Worked examples – calculation of
corresponding frequencies
8(l)
recognise that higher frequency
electromagnetic radiation has
energy to initiate reactions which
lower frequency radiation cannot
initiate
Discussion: Examples of e-m initiated reactions, e.g. photosynthesis, the
photoelectric effect (the emission of photoelectrons), photographic films.
Photoelectric Effect (If available)
Zinc rod, copper rod, ionisation
chamber with gauze lid, nanoammeter,
u.v. source, white light, sources
9(a)
explain the meaning of the term
diffraction
Demonstration: diffraction of waves
Discussion: meaning of diffraction
9(b)
show an understanding of
experiments which demonstrate
diffraction including the diffraction
of water waves in a ripple tank
with both a wide gap and a
narrow gap.
Experiments;
diffraction of water waves
diffraction of ‘laser light’
diffraction of colured light – make a slit your two thumbs, hold to the eye,
view coloured lamps – the lamps ‘spread’, red more than blue and the
narrower the slit the greater the spreading.
Ripple tank, wide and narrow slits,
objects of different diameters (e.g. pen
lid, boiling tube, petrie dish)
Laser, single slit (of adjustable width)
screen
Make a slit with two thumbs, hold to the
eye, view coloured lamps – the lamps
‘spread’, red more than blue and the
narrower the slit the greater the
spreading.
Examples including:
Oct/Nov 2010, Paper 21,
question 5(a) & (b)
May/June 2010, Paper 21,
question 5(a)
Oct/Nov 2010, Paper 2, question 6
site 5
9(c)
explain and use the principle of
superposition in simple examples.
9(d)
show an understanding of the
terms interference and
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Discussion: what happens when two waves meet
Development: principle of superposition
Discussion linked to experiments showing interference of water waves
(coherence better discussed after seeing interference of light.)
Cambridge AS Level Physical Science (8780)
Ripple tank, double dipper OR two slits
site 6
4
Syllabus ref
Learning objectives
Suggested teaching activities
Learning resources
site 7
coherence.
9(e)
show an understanding of
experiments which demonstrate
two-source interference using
water, light and microwaves.
Demonstration: double slit interference for light and microwaves
Laser or monochromatic light source,
suitable single (for monochramtic
source) and double slit, screen
Microwave transmitter and receiver,
metal plates to make suitable slits.
9(f)
show an understanding of the
conditions required if two-source
interference fringes are to be
observed.
discussion of coherence and role of wavelength
Examples including:
May/June 2011, Paper 21, question 7
May/June 2011, Paper 22, question 6
Oct/Nov 2009, Paper 21, question 5
Oct/Nov 2009, Paper 22, question 5
v1 2Y05
Cambridge AS Level Physical Science (8780)
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