The Electromagnetic Spectrum It’s more than just the rainbow

I. What is the EM spectrum? A. Electromagnetic radiation travels in the form of waves B. They have both magnetic and electrical properties C. Unlike sound waves or water waves, they can travel through space without a medium

D. These waves have a frequency and a wavelength like other waves 1. Wavelength = distance from one crest to another (λ) 2. Frequency = number of crests in one second

E. The EM spectrum is all types of EM radiation arranged according to frequency

II. Parts of the EM spectrum A. radio waves: 1. have the lowest frequency 2. also have the lowest energy 3. used for communication and radar

B. Microwaves 1. can cause certain atoms to vibrate 2. we interpret that as heat 3. used in cooking and communication

C. Infrared: given off by objects as heat D. Visible light: portion of the spectrum we can see from red (lowest frequency) to violet (highest frequency)

E. Ultraviolet: 1. just beyond where we can see 2. too much can damage the skin F. X-rays: 1. can pass through many substances 2. used in medicine and security

G. Gamma rays 1. Have the highest frequency and energy 2. Can damage DNA 3. Often used to kill cancer cells