1. A straight-line beam of light as it travels outward from its source.

• Transverse wave
• prism
• light ray

2. A lens that is thicker at the edges than at the middle. As it curves inward, it spreads light rays apart making images appear smaller.

• convex lens
• concave lens

3. A mirror that curves in on the shiny side.

• convex mirror
• concave mirror

4. A lens or a mirror that is thicker at the middle than at the edges. As it curves outward, it brings light together, making images appear larger.

• convex
• concave

5. The bouncing of a light ray off a surface.

• reflection
• refraction

6. The bending of light rays as they pass from one substance into another.

• reflection
• refraction

7. Letting all light through, so that objects on the other side can be seen clearly.

• opaque
• transparent
• transcluent

8. Letting only some light through, so that objects on the other side appear blurry.

• opaque
• transparent
• transcluent

9. Completely blocking light from passing through it.

• opaque
• transparent
• transcluent

10. A cut piece of clear glass (or plastic) with two opposite sides in the shape of a triangle or other geometric shape.

• prism
• concave lens
• concave mirror