1. Chapter 22 - The Nature of Light
Section 1 – What Is Light? pp

2. TERMS TO LEARN
Electromagnetic (EM) wave– a wave that can travel through space and matter. It consists of changing electric and magnetic fields.
Radiation – the emission of energy in the form of EM waves

3. LIGHT Light is an EM wave. Light can travel through space and matter.
A field is a region around an object that can exert a force on another object without actually touching it (ex.: a magnet is surrounded by a magnetic field that can pull a paper clip toward it).

4. AN ELECTROMAGNETIC WAVE

5. The Split Personality of Light
Scientists think that light has the properties of both a particle and a wave.
This is known as the particle-wave theory of light.

6. HOW LIGHT IS PRODUCED
Electrons in an atom move around the nucleus at different distances depending on the amount of energy they have. When an electron absorbs energy, it can jump to a new position.
This electron cannot stay at the new position for very long. It then returns to its original position, releasing the energy it absorbed in a tiny packet called a “photon”.

7. HOW LIGHT IS PRODUCED
3. The movement of electrons back and forth creates a stream of photons. This stream of photons (the EM wave) carries the energy released by the electrons.

8. THE SPEED OF LIGHT In space, the speed of light is 300,000,000 m/s.
Light travels slower in air, glass and other types of matter.
Light travels more than 880,000 times faster than sound!