In this topic, you will see how light exhibits wave properties.

Sound waves propagate through the air; therefore, air is a medium for sound waves.  Water, rope or strings, and springs can also be media for waves, but light is able to travel through the vacuum of space and does not require a medium. What allows light to travel without a medium?

The types of waves you have learned about earlier in this module are mechanical waves. Most mechanical waves are created by vibrating objects and require a medium to transmit energy. For example, sound is created when a vibrating object sets air molecules into motion, creating a pressure wave. 

Essential Questions:

• In what ways does light act as a wave?
• How does light behave as an electromagnetic wave?