Waves

3. Curving outward.
6. The distance between a point on one wave and the same point on the next wave.
9. The maximum disturbance of a wave from its undisturbed position.
12. The point on a wave with the maximum value or upward displacement within a cycle.
13. Curved inward.

1. The minimum or lowest point in a cycle.
2. The magnitude or intensity of a certain sound.
4. A constant backwards and forwards motion.
5. The number of waves produced by a source each second.
7. Vibrations that transfer energy from place to place without matter (solid, liquid or gas) being transferred.
8. A word that comes from the Greek, meaning "small".
10. How high or low a sound seems.
11. Empty space with nothing inside, not even air.