Across
- 4. takes up space and has mass
- 6. when light changes direction
- 7. where light enters the eye
- 8. unit for measuring light
- 11. an observable event
Down
- 1. to bounce off of
- 2. to go through
- 3. controls how much light enters the eye
- 5. allows light to pass through
- 8. can help to focus light
- 9. not transparent
- 10. sends an electrical signal from eye to the brain