1. Wave Properties
7SCIENCE

2. Review What are the two main types of wave? What is the difference?
Mechanical and electromagnetic
What is the difference?
Mechanical waves must travel through matter
How do you describe the shape of these waves?
Transverse and compressional waves
What are the parts of a wave?
Crest, trough, amplitude and wavelength
What type of wave are sound waves?
Mechanical, compressional

3. Wave Properties Waves have characteristics we can see and measure
If you see a wave in the ocean, the distance it rises above the normal level of the water is called the wave’s amplitude
Amplitude is half the distance between the crest and the trough in a transverse wave
In compressional waves, the amplitude is greater when particles are squeezed together

4. Amplitude
A wave’s amplitude measures the amount of energy the wave carries
Waves with large amplitudes carry more energy than those with small amplitudes
Example: bright light has a greater amplitude than dim light, and sound waves that are loud have greater amplitudes than soft sounds

5. Wavelength and Frequency
Wavelength is the distance from a crest to crest or trough to trough
Wavelength is important to the study of light: wavelength determines the color
The frequency of a wave is the number of waves that pass a point in ONE second
Measured in waves/second, called hertz (Hz)
Do short wavelengths have a higher or lower frequency? Why?
Why does a wave with a long wavelength have a low frequency?