Module 6: Waves, atoms and space

Module 6: Waves, atoms and space

Units
Candidates will be assessed on their ability to:

Use the following units:

� hertz (Hz), metre (m), newton per kilogram (N/kg) (6.01)

Waves
Candidates will be assessed on their ability to:

describe longitudinal and transverse waves in terms of frequency, wavelength and amplitude (6.02)

recall that the electromagnetic spectrum includes radio waves, microwaves, infra-red (IR), visible, ultraviolet (UV), X-rays and gamma rays (6.03)

recall the order of the electromagnetic spectrum in decreasing wavelength and increasing frequency including the colours of the visible spectrum (6.04)

recall that the energy associated with an electromagnetic wave, and thus its potential danger, increases with increasing frequency (6.05)

recall that all electromagnetic waves are transverse and travel at the same speed in a vacuum (6.06)

understand the difference between analogue and digital signals (6.07)

understand some uses of electromagnetic radiation including

� radio waves: broadcasting and communications including satellite transmissions

� microwaves: cooking and communications including satellite transmissions

� infra-red: grills, night vision, remote controls, security systems and treatment of

muscular problems

� visible light: vision and photography

� ultraviolet: sunbeds, security marking, fluorescent lamps and detecting forged bank

notes

� X-rays: observing the internal structure of objects and materials including the human

body

� gamma rays: sterilising food and medical equipment, and treatment of cancers (6.08)

understand the detrimental effects of excessive exposure of the human body to

� microwaves: internal heating of body tissue

� infra-red: skin burns

� ultraviolet: damage to surface cells (including skin cancer) and eyes

� X-rays: damage to cells (6.09)

describe the change of direction of light as it enters glass from air and as it leaves glass into air (eg, glass block, glass prism) (6.10)

understand the refraction of light in terms of the change of speed when light crosses a boundary (6.11)

recall that light and infra-red radiation pass through an optical fibre with very little energy loss (6.12)

recall that sound is transmitted as a longitudinal wave (6.13)

understand that sound with frequencies greater than 20,000 Hz is known as ultrasound and recall that human ears detect a limited range of frequencies (6.14)

describe the use of ultrasound in medical imaging and echo sounding (6.15)

Space
Candidates will be assessed on their ability to:

recall that the Moon orbits the Earth and that some other planets also have moons (NB names of moons are not required) (6.16)

understand gravitational field strength, g, and recall that it is different on other planets and the Moon to that on Earth (6.17)
explain that gravitational force

� causes the planets to orbit the Sun

� causes the Moon and artificial satellites to orbit the Earth

� causes comets to orbit the Sun (6.18)

describe how the orbit of a comet differs from that of a planet (6.19)

recall that the solar system is part of the Milky Way galaxy

� describe a galaxy as a large collection of millions of stars

� state that the Universe is a large collection of galaxies (6.20)

describe the methods used to gather evidence for life elsewhere

� soil experiments on landers (e.g. Viking)

� listening on radio wavelengths (SETI) (6.21)

describe the evolution of small stars like our Sun through stages from nebula to main sequence to red giant, white dwarf and black dwarf (6.22)

understand that gravitational forces cause a nebula to collapse to form a star (6.23)

describe the �Big Bang� theory of the origin of the Universe and consider other theories such as the �Steady State� theory (6.24)

outline the evidence in support of the current theory about the origin of the Universe

� the �Big Bang�

� red shift gives evidence that the Universe is expanding

� microwaves give evidence of the original explosion (6.25)

explain how the future of the Universe depends on the amount of mass present (6.26)

Atoms
Candidates will be assessed on their ability to:

understand the terms atomic (proton) number and mass (nucleon) number and explain the existence of isotopes (6.27)

use symbols such as 14 6 C to describe particular nuclei (6.28)

understand that radioactivity arises from the breakdown of an unstable nucleus of an atom and is a random process (6.29)

recall the three main types of radiation from radioactive sources and their comparative mass, charge and ionisation ability (6.30)

describe the properties of alpha and beta particles and gamma radiation, including their penetrating powers and their uses in smoke alarms, for controlling the thickness of sheet material and sterilising medical instruments (6.31)

recall the existence of background radiation from the Earth and from space including the regional variations in the United Kingdom, eg because of radon gas released from rocks (6.32)

describe the dangers of ionising radiations including

� radiation can cause mutations in living organisms

� radiation can damage cells and tissue

� the problems arising in the disposal of radioactive waste (6.33)

describe the problems associated with the safe disposal of radioactive waste (6.34)