| A | B |
|---|
| vibration | a back-and-forth movement of matter |
| volume | the loudness of a sound |
| pitch | how high or low a sound is |
| frequency | the number of vibrations per second |
| reflection | the bouncing of light off an object |
| refraction | the bending of light as it moves from one material to another |
| translucent | allowing only some light to pass through |
| transparent | allowing light to pass through |
| opaque | not allowing light to pass through |
| concave lens | a lens that is thicker at the edges than in the middle |
| convex lens | a lens that is thicker in the middle than at the edges |
