1. Notes 1:The Nature of Waves
Chapter 10 Section 1 (page 290)

2. What You’ll Learn Recognize that waves carry energy but not matter.
Define mechanical waves.
Compare and contrast transverse waves and compressional waves.

3. Why It’s Important
You can see and hear the world around you because of the energy carried by waves.

4. Review Vocabulary
Energy - the ability to cause change.

5. What’s in a wave? Examples of waves:
A surfer bobs in the ocean waiting for a wave.
A microwave warms up your leftover pizza.
Sound waves from your iPod brings music to your ears.
Wave - a repeating disturbance or movement that transfers energy through matter or space.

6. A falling rock has energy because it is moving.
Waves and Energy
A falling rock has energy because it is moving.
As it splashes into water, the falling rock transfers some energy to nearby water molecules, causing them to move.

7. Waves and Energy
Those molecules then pass the energy along to neighboring water molecules, which, in turn, transfer it to their neighbors.
What we see is energy traveling in the form of a wave on the surface of the water!

8. Waves and Matter
All waves carry energy without transporting matter from place to place.
When the ripples were formed by the rock, the water never actually moved, just simply the energy carried by the waves moved forward.
All waves are produced by something that vibrates.
The rock ‘shakes’ or vibrates the water.

9. Mechanical Waves Medium - matter in which a wave travels.
Sound waves travel through the air.
Ocean waves move through water.
A medium can be a solid, liquid, or gas.
Mechanical waves need a medium, but not all waves need a medium (such as radio waves).

10. Transverse Waves
Transverse Wave - wave for which the matter in the medium moves back and forth at right angles to the direction the wave travels; has crests and troughs.

11. Compressional Waves
Compressional Wave - a wave for which the matter in the medium moves back and forth along the direction that the wave travels.

12. Summary
A wave is a repeating disturbance or movement that transfers energy through matter or space.
Waves carry energy without transporting matter.
Waves are produced by something that is vibrating.
Mechanical waves must travel in matter.
Mechanical waves can be transverse waves or compressional waves.
In a transverse wave, matter in the medium moves at right angles to the wave motion.
In a compressional wave, matter moves back and forth along the direction of the wave motion.