6.6 Electromagnetic Waves 25 March 2017 6.6 Electromagnetic Waves Think about: How well behaved you are How good you are at science How much you like chocolate hob nobs

Aims Describe visible light as part of the electromagnetic spectrum State other types of radiation

Electromagnetic waves

Travel through empty space

Travel at 300 000 km/s

Transverse waves

They transfer energy

LIGHT SOUND Light vs Sound Example of wave Type of wave Speed in air / km/s Material of medium

LIGHT SOUND Light vs Sound Example of wave Type of wave Transverse Longitudinal Speed in air / km/s 300 000 340 Material of medium No material required Solid, liquid, gas

LIGHT SOUND LIGHT SOUND Example of wave LIGHT SOUND Type of wave Speed in air / km/s Material of medium Example of wave LIGHT SOUND Type of wave Speed in air / km/s Material of medium

Electromagnetic radiation actually comes in packets or lumps Electromagnetic radiation actually comes in packets or lumps. I call these packets ‘quanta’. A quanta of light is called a photon. Nobel prize please…

The higher the frequency, the more energy the photon has

Intensity Energy of each photon Number of photons arriving each second

The electromagnetic spectrum

Accelerated electrons Radio waves Accelerated electrons

Radiowaves Communications: TV, mobile phones, local radio, police

Molecular transitions Microwaves Molecular transitions

Microwaves Microwaves ovens, communicating with satellites, RADAR

Molecular transitions Infrared Molecular transitions

Infra-red Search and rescue teams, detect circulation problems, (cancer, arthritis), astronomy, burglar alarms

Atomic transitions and electron acceleration Light Atomic transitions and electron acceleration

Ultraviolet Atomic transitions

UV Produce vitamin D in our skin, suntan, skin cancer

Electron transitions and collisions X-rays Electron transitions and collisions

X-rays X-rays (bones, teeth), check welds and joints, food

Nuclei transitions and annihilation Gamma rays Nuclei transitions and annihilation

Gamma rays Make Hulks, sterilise food and utensils, tracers, radiotherapy

3.13 recall the detrimental effects of excessive exposure of the human body to electromagnetic waves

Make an EM spectrum booklet Guest starring Mr. Simon Porter

The EM spectrum You now have seven sections to fill in with information regarding the seven types of electromagnetic radiation Include uses, dangers, detectors, examples and origins if you can The better you make it the better it will help your revision