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OverviewEdit

P1 Part 2 covers the energy sources used to generate electricity, waves and evidence for the big bang.

P1.4 Methods we use to generate electricityEdit

Various energy sources can be used to generate the electricity we need. We must carefully consider the advantages and disadvantages of using each energy source before deciding which energy source(s) it would be best to use in any particular situation. Electricity is distributed via the National Grid.

P1.5 The use of waves for communication and to provide evidence that the universe is expandingEdit

Electromagnetic radiations travel as waves and move energy from one place to another. They can all travel through a vacuum and do so at the same speed. The waves cover a continuous range of wavelengths called the electromagnetic spectrum. Sound waves and some mechanical waves are longitudinal, and cannot travel through a vacuum. Current evidence suggests that the universe is expanding and that matter and space expanded violently and rapidly from a very small initial "point", ie the universe began with a "big bang".

Lesson SummariesEdit

Specification Reference Summary of Specification contents. Learning Outcomes

P1.4.1 Generating electricityEdit

P1 Lesson 17&18 How a nuclear or fuel burning power station worksEdit

a In some power stations an energy source is used to heat water. The steam produced drives a turbine that is coupled to an electrical generator. Understand the purpose of the main parts of a power station.
Know that different energy sources which heat the water include: the fossil fuels (coal, oil and gas) which are burned to heat water or air, uranium and plutonium, when energy from nuclear fission is used to heat water, biofuels that can be burned to heat water.
Know that, of the fossil fuel power stations, gas-fired have the shortest start-up time.
Be aware of the advantages of pumped storage systems in order to meet peak demand, and as a means of storing energy for later use.

P1 Lesson 19&20 The use of water, wind and geothermal energy resources to generate electricityEdit

b Water and wind can be used to drive turbines directly. Know the basic principles by which wind turbines operate.
Know that water can be used to drive turbines in a variety of ways, which include, but are not limited to, waves, tides and the falling of water in hydroelectric schemes.
d In some volcanic areas hot water and steam rise to the surface. The steam can be tapped and used to drive turbines. This is known as geothermal energy. Know the basic principles of how geothermal energy is used.

P1 Lesson 21 Solar energy and advantages of small scale energy generationEdit

c Electricity can be produced directly from the Sun’s radiation. Know that solar cells can be used to generate electricity.
e Small-scale production of electricity may be useful in some areas and for some uses, eg hydroelectricity in remote areas and solar cells for roadside signs Be able to describe the advantages and disadvantages of the use of solar cells in generating electricity.

P1 Lesson 22&23 Effect of different energy resources on the environmentEdit

f Using different energy resources has different effects on the environment. Understand effects on the environment such as: the release of substances into the atmosphere, the production of waste materials, noise and visual pollution, the destruction of wildlife habitats.
Understand that carbon capture and storage is a rapidly evolving technology.
Understand that to prevent carbon dioxide building up in the atmosphere we can catch and store it; some of the best natural containers are old oil and gas fields, such as those under the North Sea.
Evaluate different methods of generating electricity given data including start-up times, costs of electricity generation and the total cost of generating electricity when factors such as building and decommissioning are taken into account. The reliability of different methods should also be understood.

P1.4.2 The National GridEdit

P1 Lesson 24&25 The National GridEdit

a Electricity is distributed from power stations to consumers along the National Grid. Identify and label the essential parts of the National Grid.
b For a given power, increasing the voltage reduces the current required and this reduces the energy losses in the cables. Know why transformers are an essential part of the National Grid.
c The uses of step-up and step-down transformers in the National Grid

P1.5.2 ReflectionEdit

P1 Lesson 27&28 ReflectionEdit

a The ‘normal’ is a construction line perpendicular to the reflecting surface at the point of incidence. Draw diagrams showing rays of light being reflected from a plane mirror, labelling incident and reflected rays, angles of incidence and reflection, and the normal.
b The angle of incidence is equal to the angle of reflection.
c The image produced in a plane mirror is virtual, upright and laterally inverted. Understand how an image is formed by a plane mirror, and why it is virtual.

P1.5.1 General properties of wavesEdit

P1 Lesson 29&30 Basic Properties of WavesEdit

a Waves transfer energy. Understand that in a transverse wave the oscillations are perpendicular to the direction of energy transfer.
b Waves may be either transverse or longitudinal. Understand that in a longitudinal wave the oscillations are parallel to the direction of energy transfer.
c Electromagnetic waves are transverse, sound waves are longitudinal and mechanical waves may be either transverse or longitudinal. Recall examples of transverse and longitudinal waves
d All types of electromagnetic waves travel at the same speed through a vacuum (space). Describe similarites between electromagnetic wave eg, speed, travel through a vacuum, they are transverse.
f Longitudinal waves show areas of compression and rarefaction. Explain the terms ‘compression’ and ‘rarefaction’ and how they are formed.
I The terms ‘frequency’, ‘wavelength’ and ‘amplitude’. Explain the terms ‘frequency’, ‘wavelength’ and ‘amplitude’ and be able to annotate a diagram to show these terms.

P1 Lesson 31&32 Reflection, Refraction and DiffractionEdit

g Waves can be reflected, refracted and diffracted. Describe the circumstances where a wave is reflected, refracted or diffracted.
Be able to complete wavefront diagrams for reflection, refraction and diffraction.
h Waves undergo a change of direction when they are refracted at an interface. Know that waves are not refracted if travelling along the normal.

P1 Lesson 33 The Wave EquationEdit

I The terms frequency, wavelength and amplitude. Be able to use the equation, knowing that v is speed in metres per second (m/s) f is frequency in hertz (Hz) and λ is wavelength in metres (m).
j All waves obey the wave equation: v = f × λ

P1 Lesson 34&35 Uses of Radio waves, Microwaves, Infra Red and Visible light for communication.Edit

k Radio waves, microwaves, infrared and visible light can be used for communication. Describe situations in which waves are typically used for communication, eg: radio waves – TV and radio (including diffraction effects), microwaves – mobile phones and satellite television, infrared – remote controls, visible light – photography.

P1.5.3 SoundEdit

P1 Lesson 36&37 SoundEdit

a Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound. Know how sound waves are produced.
b The pitch of a sound is determined by its frequency and loudness by its amplitude. Understand the relationship between the pitch of a sound and the frequency of the sound wave.
c Echoes are reflections of sounds. Understand how echoes are formed.

P1.5.4 Red-shiftEdit

P1 Lesson 38 Evidence for the big bangEdit

a If a wave source is moving relative to an observer there will be a change in the observed wavelength and frequency. This is known as the Doppler effect. Be able to explain the Doppler effect.
Know that when the source moves away from the observer, the observed wavelength increases and the frequency decreases; when the source moves towards the observer, the observed wavelength decreases and the frequency increases.
b There is an observed increase in the wavelength of light from most distant galaxies. This effect is called the ‘red-shift’. Be able to explain the term ‘red- shift’.
c How the observed ‘red-shift’ provides evidence that the universe is expanding and supports the ‘Big Bang’ theory. Know that the further away the galaxies are, the faster they are moving, and the bigger the observed increase in wavelength.
Be able to explain how ‘red-shift’ provides evidence that the universe is expanding.
d Cosmic microwave background radiation (CMBR) is a form of electromagnetic radiation filling the universe. Know that the ‘Big Bang’ theory indicates that the universe began from a very small initial point.
e The ‘Big Bang’ theory is currently the only theory that can explain the existence of CMBR. Know that CMBR comes from radiation that was present shortly after the beginning of the universe.

Summary of P1.4 and P1.5Edit

P1 Lesson 39 Summary of P1.4 and P1.5Edit

Summary of section P1.4 and P1.5