Light and the

Electromagnetic Spectrum

What Kind of Wave Is Light and What Vibrates to Make It?

• When an electric charge vibrates, the electric field around it changes, creating a changing magnetic field.

http://www.youtube.com/watch?feature=player_detailpage&v=hajIIGHPeuU

• When a magnet moves, the magnetic field around it changes, creating a changing electric field.

• The magnetic and electric fields create each other again and again.

An EM wave travels in all directions.

So…. what kind of wave is light?

What is Light Made of And How do We Know?

Two Theories1. Waves

2. Particles

Photons!!

Double Slit Experiment – Thomas Young 1803

What Types of Light Are There?

The Electromagnetic Spectrum

RedOrangeYellowGreenBlueIndigoViolet

ROY G BIV

How to Remember Order of Visible Light?

What Does Light Have To Do With Astronomy?

Age? Composition?

• Neon

• Argon

• Helium