GCSE Science A Physics 1 Waves Learning Outcomes Characterise waves in terms of their wavelength, frequency, speed and amplitude. Distinguish between the different regions of the electromagnetic spectrum. Including their uses and dangers Appreciate that all the regions of the electromagnetic spectrum transfer information and energy. Characterise waves in terms of their wavelength, frequency, speed and amplitude. Distinguish between the different regions of the electromagnetic spectrum. Including their uses and dangers Appreciate that all the regions of the electromagnetic spectrum transfer information and energy.

GCSE Science A Physics 1 Waves Key Words: Electromagnetic Spectrum: The collective name for radio waves, microwaves, infrared etc... Wavelength: The “length” of one complete wave. Frequency: The number of complete waves passing a point per second. Amplitude: The height of the wave Electromagnetic Spectrum: The collective name for radio waves, microwaves, infrared etc... Wavelength: The “length” of one complete wave. Frequency: The number of complete waves passing a point per second. Amplitude: The height of the wave

GCSE Science A Physics 1 Waves

GCSE Science A Physics 1 Waves Start Consider a wave on the wave machine (click start to begin)… Stop the motion by clicking again anywhere on the page – can you see that there is a repeat in the pattern? Using the ruler, measure the distance between the pattern starting and the repeat starting. You should find that the length is about 7.7cm – this is the WAVELENGTH of the wave. Show/ hide ruler

GCSE Science A Physics 1 Waves Using the ruler, measure the distance between the central starting point (the blue dotted line) and the maximum distance moved by any particle. Start In the same way…. Stop the motion by clicking again anywhere on the page. You should notice that the individual parts of the wave move between two extremes. You should find that the length is about 1.3cm – this is the AMPLITUDE of the wave. Show/ hide ruler

GCSE Science A Physics 1 Waves wavelength (m)amplitude (m) cresttrough Label the diagram by moving the terms from the box below to their correct positions on the diagram.

GCSE Science A Physics 1 Waves Wavelength (m) = amplitude (m) = 1. Number of complete waves = 30m 2m Wavelength (m) = amplitude (m) = 2. Number of complete waves = 2m 0.5m Wavelength (cm) = amplitude (cm) = 3. Number of complete waves = 4.5cm 3cm Answers

GCSE Science A Physics 1 Waves Wavelength (m) = amplitude (m) = 1. Number of complete waves = 30m 2m Wavelength (m) = amplitude (m) = 2. Number of complete waves = 2m 0.5m Wavelength (cm) = amplitude (cm) = 3. Number of complete waves = 4.5cm 3cm 3 30/3 = 10 2/2 = 1 6 2/6 = /2 = /1.5 = 3 3/2 = 1.5

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum All EM Waves; Travel at the speed of light (3x10 8 m/s). All carry Energy and Information. All EM Waves; Travel at the speed of light (3x10 8 m/s). All carry Energy and Information.

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Used for communicating over vast distances Transmitting TV and radio programmes

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Heating food. Some people are concerned about possible health risks with the signals from mobile phones. In particular; long term exposure for children Mobile phone signals

GCSE Science A Physics 1 Waves Waves and communication Satellite Communications Geostationary orbit: Satellite orbits above the same point on the Earth at all times The satellite takes 24 hours to orbit the Earth. Satellites (mainly) use microwaves to communicate with base stations on Earth. Fibre Optic Cable Use infrared to send information down special cable using “total internal reflection” Speed of infrared radiation in the cable is 2x10 8 m/s Satellite Communications Geostationary orbit: Satellite orbits above the same point on the Earth at all times The satellite takes 24 hours to orbit the Earth. Satellites (mainly) use microwaves to communicate with base stations on Earth. Fibre Optic Cable Use infrared to send information down special cable using “total internal reflection” Speed of infrared radiation in the cable is 2x10 8 m/s

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Heating food (toasters, grills) Can cause skin burns Heating people (patio warmers) Remote controls Fibre-optic cables (broadband)

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Seeing Can cause eye damage if very bright Communication CD-players and Blu-Ray Lasers

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Used to sterilise water.Can ionise skin cells causing sunburn and skin cancer. Detected forged notes Sick RavesCan cause eye damage (cataracts)

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Medical ImagingX-rays are highly ionising, and can cause cancer anywhere within the body. Detected by some space telescopes.

GCSE Science A Physics 1 Waves The Electromagnetic Spectrum UsesDangers Used for medical imagingGamma Rays are highly ionising, and can cause cancer anywhere within the body. Sterilisation of medical equipment Chemotherapy

GCSE Science A Physics 1 Waves What if we had never discovered EM – waves (excluding visible light)? Write an account of what the world would be like in the absence of these waves. How would it be different, and what would be our main challenges as human beings? What if we had never discovered EM – waves (excluding visible light)? Write an account of what the world would be like in the absence of these waves. How would it be different, and what would be our main challenges as human beings?