Download GCSE Physics criteria sheet

GCSE Physics criteria sheet
PD1
WAVES IN ACTION
Candidates should be taught:
3a about the reflection, refraction and diffraction of waves including light and
sound as examples of transverse and longitudinal waves.
3b the meaning of frequency, wavelength and amplitude of a wave
3c the quantitative relationship between the speed, frequency and wavelength of
a wave
3d that waves transfer energy without transferring matter
3e that the electromagnetic spectrum includes radio waves, microwaves, infrared, ultraviolet waves, X-rays and gamma rays
3f some uses and dangers of microwaves, infra-red and ultraviolet waves in
domestic situations
3g some uses of X-rays, and gamma rays in medicine
3h how information can be transmitted along optical fibres
3i that radio waves, microwaves, infrared and visible light carry information
over large and small distances
3l about sound and ultrasound waves and some medical uses of
ultrasound
3m that longitudinal and transverse waves are transmitted through the Earth
producing wave records that provide evidence for the Earth’s layered structure
RATIONALE:
This module explores the ways in which waves affect our lives in domestic situations, communications and
medicine. The wave concept encompasses not only the sound and light of everyday experience but also the
full electromagnetic spectrum and ultrasound.
The nature and properties of waves are covered. The measurable quantities of speed, frequency and
wavelength are linked by the wave equation, and the effects on waves of reflection, refraction and
diffraction are explored. Work in the module also includes the main features and uses of sound, ultrasound
and the electromagnetic spectrum. A more detailed study of light includes reflection and refraction
(including positive lenses and total internal reflection). A key idea encountered in this
module that of the electromagnetic spectrum (including the use of X-rays in medicine). This idea underpins
later work and will be tested in the terminal question papers.
There is a link with module PD6 where ideas about waves are developed in connection with the layered
structure of the Earth and radioactivity. There is also a link with module CD3 where the theory of plant
tectonics is explored. There are links with the speed of sound in module PD3 where pupils learn to
calculate speed from distance and time.
KEY DEFINITIONS & TERMS:
Wavelength ()– Length occupied by 1 complete wave (distance from one crest to adjacent crest), in metres
Frequency (f) – Number of complete waves or oscillations produced per second, in Hertz.
Amplitude (a) – maximum displacement (vibration) of the wave, measured in metres.
Velocity (v) – Speed at which a wave travels, in metres per second.
Longitudinal wave – Oscillations are along the wave in the direction of travel, eg, Sound waves and P waves.
Transverse waves – Oscillations are at right angles to the direction of travel, eg, Light waves and S waves.
Compressions – Points on a longitudinal wave where particles are pushed closer together (higher pressure).
Rarefactions – Points on a longitudinal wave where particles are pulled further apart (lower pressure).
Diffraction – When waves spread out going through a gap or around an edge.
Refraction – When waves change direction & move towards the normal line entering a denser medium.
Total Internal reflection – When waves are reflected back inside a material if they hit the surface at greater
than the critical angle (about 42 for glass).
Ultrasound – High frequency sound waves that are beyond human hearing (over 20,000Hz).
Foundation & Higher
state and recognise that water ripples and light
travel as transverse waves
state and recognise that waves can be refracted
describe the main features of transverse waves
° crest
° trough
° amplitude
° wavelength
° frequency
state and recognise that sound travels as a
longitudinal wave
state and use the qualitative relationship between
frequency and wavelength for waves of the same
speed:
 the frequency of the waves increases as their
wavelength decreases for waves at constant
speed and vice versa
state & use the qualitative relationship between
wave speed & wavelength for waves of constant
frequency
 the wavelength decreases as the wave
speed increases and vice versa
state and describe how light can be internally reflected in:
 optical fibres
 binoculars
 periscopes
 bicycle reflectors
 endoscopes
draw simple ray diagrams to illustrate refraction or reflection
(including the normal line)
state and recognise that the frequency of ultrasound is
higher than the upper threshold of human hearing (above
20,000Hz)
describe applications of ultrasound:
 body scans
 breaking down kidney and other stones
 sonar
 cleaning
describe the physical state of each layer of the Earth
 crust is a solid
 mantle contains solid and liquid rock
 outer core is a liquid
 inner core is a liquid (denser)
state that waves can be transmitted through the Earth and that
this provides evidence for the structure inside the Earth
describe longitudinal P waves and transverse S waves.
Higher
state and recognise that waves can be diffracted
identify & describe features of transverse & longitudinal
waves
° crest
° trough
° amplitude
° wavelength
° frequency
° compression
° expansion (rarefaction)
state and explain that waves transfer energy without
transferring matter
describe the motion of particles in longitudinal and
transverse waves
state and use the quantitative relationship between wave
speed, frequency and wavelength: (change of subject
required)
Velocity = frequency x wavelength
V=f
Velocity in m/s
Wavelength in m
Frequency in Hz
explain total internal reflection in the following
contexts:
 binoculars
 periscopes
 bicycle reflectors
 endoscopes
by drawing or interpreting simple ray diagrams
describe application of total internal reflection in fibre
optics
explain how ultrasound is used in:
 body scans (reflection from different layers)
 breaking down accumulations in body such as
kidney stones
 sonar and echo sounding
 cleaning
describe how waves transmitted through the Earth can be
used to provide evidence for its structure
 longitudinal P waves travel through solid and
liquid (so they are faster)
 transverse S waves cannot travel through liquid
 longitudinal P waves can travel through all layers
of the Earth
 transverse S waves cannot travel through the
outer core