1. Construct ray diagram

2. Sound L.O.:  Describe how sound waves are produced.  Explain how a sound echo is produced.  State the main differences between light and sound waves.

3. As you watch this animation think how to answer these questions: 1)What type of waves are sound waves? Sound waves are longitudinal waves. They vibrate along the direction they travel in. 2) How is a sound echo produced? A sound echo is a reflection of sound. 3) What happens if walls are covered in soft fabric? The fabric will absorb sound instead of reflecting it and no echo will be heard.

4. Watch the bell jar animation and decide. Can sound travel in vacuum?

5. Tasks: 1)Workbook page 118, Q: 1,2 &4 2)Sound echoes worksheet

6. Sound L.O.:  Describe how sound waves are produced.  Explain how a sound echo is produced.  State the main differences between light and sound waves.