Across
- 1. / a material that can be seen or touched
- 3. / created by vibrations that move through air, water or solids
- 4. / vibrating energy that looks like waves
- 6. / the rate at which something moves
- 8. / a movement that produces sound
- 9. / invisible mixture of gases
- 10. / measured in distance
Down
- 2. / caused by the reflection of sound waves
- 5. / to take in energy
- 7. / can use this to make objects