Download WAVES, LIGHT AND SOUND, ELECTRICITY AND MAGNETISM,

WAVES, LIGHT AND SOUND, ELECTRICITY AND MAGNETISM, EARTH IN SPACE
Waves
- Waves transfer energy from one point to another.
- Transverse waves vibrate at right angles to the wave direction.
- Longitudinal waves vibrate back and forward with the wave.
- give examples of transverse and longitudinal waves.
- describe, using simple wavefront diagrams, how waves are reflected and
refracted.
- Know the meanings of frequency, wavelength and amplitude of a wave.
- know the wave equation: speed = frequency X wavelength (v=fλ)
Amplitude
Wavelength
Sound
- describe experiments to demonstrate that sound can travel through different
materials at different speeds but cannot travel through a vacuum.
- relate pitch and loudness of sound to its waveform displayed on a CRO.
- recall that the range of human hearing is 20 Hz to 20 kHz and that the upper limit
decreases with age.
- recall that frequencies greater than 20 kHz are called ultrasound.
- describe damaging effects of loud sounds on the ear and understand the need to control
noise levels in the environment.
- recall that sound is reflected so that the angle of incidence = the angle of reflection.
- describe applications of echoes and carry out simple calculations on the echo principle.
- describe some applications of ultrasound in industry and medicine.
Light
- recall that luminous objects are seen by the light they emit and that all other objects
are seen by the light they reflect.
- explain with the help of ray diagrams the formation of shadows by point and extended
sources of light.
- light is reflected from flat surfaces so that the angle of
incidence = the angle of reflection
- a change of speed causes light to be refracted at air/glass,
glass/air, air/water, and water/air boundaries.
- know that when light enters glass it slows & is bent in
towards the normal (when it goes out of glass it bends out away from normal.
- use a wave model to explain refraction of light at a plane surface using simple plane
wavefront diagrams.
- describe how light is dispersed by prisms and understand that a spectrum can be
produced because different colours of light are refracted by different amounts.
The electromagnetic spectrum
Radio
Microwave
Infra red
Visible
Ultra
Violet
X-ray
Gamma
- describe some uses & dangers of microwaves, infrared and ultraviolet.
- describe some uses of X-rays and gamma-rays in medicine.
- describe uses of radiowaves, microwaves, infra red and visible light in communication.
Electricity and Magnetism
Static charge
- recall that insulating materials can be charged by friction and explain this in terms of
electrons being removed or added.
- understand that positively charged objects have less electrons and negatively charged
objects have more electrons.
- describe the dangers and use of electrostatic charges.
Charge flow
- understand that an electric current is a flow of electrons and that it is in the opposite
direction to that of a conventional current.
- recall that charge is measured in coulombs.
- know the charge equation: charge = current X time (Q=It)
- current is a flow of free electrons which generates heat when they collide with atoms.
Electric circuits
- understand the role of conductors, insulators and switches in simple series and parallel
circuits.
- know the symbol for a cell and its polarity ( + - )
- know simple circuit symbols
- measure current and voltage in series and parallel circuits.
- in a series circuit the current is the same everywhere.
- in a series circuit the sum of the voltages is equal to voltage across the whole circuit.
- in a parallel circuit the sum of the currents in the branches is equal to the current
entering the parallel section.
- voltages across components in parallel are equal.
- calculate the total resistance of resistors in series. R = R1 + R2
- calculate the resistance of two equal resistors in parallel. (½ of one of the resistors)
- calculate any number of resistors in series and/or parallel
Any number of parallel resistors calculated using: 1 = 1 + 1 + 1
RT R1 R2 R3
Ohm’s Law
- plot and interpret voltage - current graphs for metallic conductors at constant
temperature.
- state and use Ohm’s Law in the form V = IR
- plot and interpret voltage-current graphs for a filament bulb. (Resistance increases as
the current increases.)
- understand that voltage is the energy transferred per unit charge.
- know the equations:
Energy = power x time
Power = voltage x current
Using electricity
- understand one-way and two-way switching.
- describe how to wire a fused three pin plug.
- understand the functions of live and neutral wires and
how the earth wire and fuse protect the user from electric
shock.
- describe how double insulation protects the user.
- understand the positioning of switches and fuses on the live side of appliances.
- calculate the costs of using electricity from meter readings.
- understand the meaning of the kilowatt hour and calculate the cost of using electrical
appliances using their power rating. (Energy = power X time)
Electromagnetic induction
-current can be induced in a conductor by either moving the wire or a magnet and by
changing the current in a neighbouring conductor.
- know the difference between a.c. and d.c.
- recall that a.c. generators are used in the generation of electricity.
- describe how step-up and step-down transformers
- are used in the transmission of electricity, including the relationship between the
number of turns and voltage across the coils.
Ns = Vs
Np
Vp
- understand that stepping up the voltage reduces energy losses in the grid.
Earth in Space
- recall the names and position of the Sun and 8 planets. Recall, evaluate and discuss the
historical evidence for the heliocentric solar system as opposed to the geocentric.
- know that gravity provides the centripetal force which acts towards the centre of
every astronomical object and that this force determines the motion of the planets and
comets round the Sun and satellites round the planets.
Stars
- Know that studies of the light from stars, including our Sun, show that they are
composed mainly of hydrogen and helium and that their energy is supplied by the fusion
of hydrogen into helium, and describe how stars are formed.
- Know that the stability of stars depends on the balance between gravitational
force and gas/radiation pressure;
The Universe
- Recall that the Universe began as a Big Bang which, according to current measurements,
occurred 12–15 billion years ago;
- Recall that evidence for the Big Bang includes that light from other galaxies is shifted
to the red end of the spectrum, and that this can be explained by space expanding;
The Structure of the Earth
- Know the Earth is divided into layers;
- Know the topmost layer is the lithosphere, which is comprised of the crust and the solid
portion of the upper mantle;
- Explain the cause of earthquakes and volcanoes (Wegener’s Theory).