4.3 Light and the Electromagnetic Spectrum Chapter 4 notes

A little vocab Radiant energy – energy, such as light, that travels by radiation Electromagnetic radiation – the transmission of energy in the form of waves that extend from the longest radio waves to the shortest gamma rays

Electromagnetic spectrum diagram

Wavelengths longer than visible light 1. Radio waves longest wavelength and lowest energy and frequency  different wavelengths have different uses radio and television broadcasting microwaves and radar Magnetic resonance imaging (MRI) uses radio waves to get an image of the inside of our bodies

Still longer 2. Microwaves shortest wavelength and highest frequency of all radio waves  used in microwave ovens to heat up water particles  used in telecommunications with satellites and to learn more about the composition, motion and structure of distant objects  shorter microwaves are used in remote sensing, like radar, to locate and object and determine its speed also used in weather forecasting

And longer again 3. Infrared Waves Longer wavelength and lower energy and frequency than light Used to control TV sets or read discs in a computer Infrared images show the warmest parts of objects

wAvelengths shorter than visible light 1. Ultraviolet waves Shorter wavelengths and higher energy and frequency than light Enables our body to make Vit D but can also cause sunburns and skin cancer  Can be used to detect fingerprints or kill bacteria in food, water and medical supplies

Shorter cont 2. X rays Much shorter wavelengths and higher energy and frequency than UV waves Used to photograph teeth and bones Low doses can form images of internal organs Shields are used to reduce exposure

Shorter still 3. Gamma rays Highest energy and frequency and the shortest wavelengths Result from nuclear reactions Focussed bursts are used to kill cancer cells