1. 4.3 Light and the Electromagnetic Spectrum
Chapter 4 notes

2. 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

3. Electromagnetic spectrum diagram

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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