CH+17+Vocabulary

Vocabulary Chapter 17

A ** [|mechanical wave] ** is a disturbance in matter that carries energy from one place to another. Recall that energy is the ability to do work. In a wave pool, each wave carries energy across the pool. You can see the effects of a wave's energy when the wave lifts people in the water.

Mechanical waves require matter to travel through. The material through which a wave travels is called a ** medium **. Solids, liquids, and gases all can act as mediums. In a wave pool, waves travel along the surface of the water. Water is the medium. Waves travel through a rope when you shake one end of it. In that case, the medium is the rope.

A mechanical wave is created when a source of energy causes a vibration to travel through a medium. A vibration is a repeating back-and-forth motion. When you shake a rope, you add energy at one end. The wave that results is a vibration that carries energy along the rope.

The highest point of the wave above the rest position is the ** crest **.

The lowest point below the rest position is the ** trough ** ( trawf ).

A ** transverse wave ** is a wave that causes the medium to vibrate at right angles to the direction in which the wave travels.
 * [[image:http://www.pearsonsuccessnet.com/ebook/products/0-13-069977-2/hsp00602c04.gif]] ||  ||
 * **Figure 2** A transverse wave causes the medium to vibrate in a direction perpendicular to the direction in which the wave travels. In the wave shown here, each point on the rope vibrates up and down between a maximum and minimum height. **A** The ribbon is at a crest. **B** The ribbon is at the rest position. **C** The ribbon is at a trough. ||

An area where the particles in a medium are spaced close together is called a ** compression ** (kum presh un).

An area where the particles in a medium are spread out is called a ** r arefaction **(rehr uh fak shun).

A ** longitudinal wave ** (lawn juh too duh nul) is a wave in which the vibration of the medium is parallel to the direction the wave travels.

Ocean waves are the most familiar kind of surface waves. A ** surface wave ** is a wave that travels along a surface separating two media.
 * [[image:http://www.pearsonsuccessnet.com/ebook/products/0-13-069977-2/hsp00606c04.jpg]] ||  ||
 * **Figure 4** As the ocean wave moves to the right, the bobber moves in a circle, returning to its original position. ||

 Electromagnetic Wave Lengths

Annotated Time Line Assignment: Time line that includes a brief description of the key facts. Include:
 * Brief description of each wave component
 * Show frequency and how that changes within the electromagnetic spectrum
 * Show wavelength and how that changes within the electromagnetic spectrum
 * Color/Pictures/Examples
 * Be neat!