1. Waves

2. Objectives
Given a diagram, be able to identify the parts of a transverse and a compression wave
Given an illustration, be able to identify the amplitude, frequency, and wavelength
CLE Investigate the properties and behaviors of mechanical and electromagnetic waves.

3. Wave Properties Ways waves differ How much energy they carry
How fast they travel

4. Wave Properties How they look Transverse waves have
crests – the highest points, and troughs – the lowest points
Compressional waves have dense regions called compressions and less dense regions called rarefactions

5. Crest vs Trough

6. Wave Properties
Wavelength – the distance between two identical points

7. Frequency
Frequency – how many wavelengths pass a fixed point each second

8. Frequency Expressed in hertz (Hz)
As frequency increases, wavelength decreases
The frequency of a wave equals the rate of vibration of the source that creates it

9. Frequency
Speed of wave depends on properties of the medium it is traveling through
Wave velocity describes how fast the wave moves forward.
Velocity =
wavelength X frequency

10. Frequency Light waves travel faster than sound waves
Sound waves travel faster in liquids and solids than in gases
Light waves travel faster in gases and empty space than in liquids and solids

11. Amplitude Amplitude – a measure of the energy in a wave
The more energy a wave carries, the greater its amplitude

12. Amplitude
Amplitude of compressional waves is related to how tightly the medium is pushed together at the compression

13. Amplitude
The denser the compressions, the larger the amplitude is and the more energy the wave carries
The less dense the rarefactions, the larger the amplitude and the more energy the wave carries

14. Amplitude

15. Amplitude Amplitude of transverse waves
The distance from the crest or trough of a wave to the normal position of the medium
Example: how high an ocean wave appears above the water level

16. Amplitude

18. In a thunderstorm, why do you see lightning before you hear the thunder?
Light waves travel much faster than sound waves.

19. Thunder & Lightning

20. If a wave has a high point and a low point, is it a compressional or transverse wave?

21. Section Check 2
Answer
Transverse waves have alternating high points, called crests, and low points, called troughs.
FL: SC.A.2.4.6

22. What is the wavelength of a wave?

23. Section Check 2
Answer
A wavelength is the distance between one point on a wave and the nearest point just like it.
FL: SC.A.2.4.6

24. Which of the following refers to the number of wavelengths that pass a fixed point each second?
A. frequency
B. period
C. wavelength
D. wave speed

25. The answer is A. Period is a length of time, and wavelength is a distance.