1. 8th Grade integrated science
What are Waves?
8th Grade integrated science

2. Wave A disturbance that transfers energy from place to place.
Energy: the ability to do work.

3. What Carries Waves Medium: the material through which a wave travels.
Sound Waves-Air
Water waves-Surface of the water
Waves that require a medium through which to travel are called mechanical waves. Waves that don’t require a medium are called electromagnetic waves.

4. What Causes Waves?
Mechanical waves are produced when a source of energy causes a medium to vibrate.
Vibration: repeated back and forth, side to side, or up and down motion.

5. Types of Waves Mechanical Waves are classified by how they move
Two types: Transverse and Longitudinal.
Transverse: As a transverse wave moves, the particles of the medium move across, or at a right angle to the direction of the wave.
Crest: high part of a transverse wave.
Trough: low part of a transverse wave.

7. Longitudinal Waves
Move the medium parallel to the direction in which the waves travel.
Example: Coils being pulled apart. Sound waves.

8. Assessment Questions What is a mechanical wave?
How are mechanical waves produced?
What are the two types of mechanical waves?
Suppose you are a particle of water in a lake. Describe what happens to you when a motorboat passes by. Make sure and use the words vibration, crest, and trough in you answer.

9. 8th Grade Integrated Science
Properties of Waves
8th Grade Integrated Science

10. Properties
Amplitude
Wavelength
Wave Height
Frequency
Speed

11. Amplitude
Maximum distance that the particles of the medium carrying the wave move away from their rest positions.
Amplitude

12. Wavelength and Wave Height
Distance from crest to crest (or trough to trough, one complete cycle) is wavelength
Distance from crest to trough is wave height
Wave height is twice as much as amplitude
Wavelength
Wave Height

13. Frequency
The number of complete waves that pass a given point in a certain amount of time.
Measured in Hertz (Hz). A wave that occurs once every second has a frequency of 1 Hz.

14. Speed
The speed, wavelength, and frequency of a wave are related to one another by mathematical formulas.
Speed = Wavelength x Frequency
Frequency = Speed / Wavelength
Wavelength = Speed / Frequency

15. Assessment Questions What are the four basic properties of waves?
Which wave properties are distances?
Which properties are measured relative to time?
What formula relates speed, wavelength, and frequency?
A wave’s frequency is 2 Hz and its wavelength is 4 m. What is the wave’s speed?