# Physical Science B – Lesson # 15 (3-16-2020)

Waves

### Unit:

Physical Science B – Unit 8 (Mr. Tyler Version)

### Objectives:

• Explain that waves transfer energy, not matter.
• Distinguish between mechanical and electromagnetic waves.
• Summarize the major properties and behavior of waves, including (but not limited to) wavelength, frequency, amplitude, speed, refraction, reflection and diffraction.

### Vocabulary/Definitions

amplitude: How far the medium (crests and troughs, or compression and rarefaction) moves from rest position (the place the medium is when not moving).

compression: When the particles of a longitudinal wave are close together.

compressional (longitudinal) wave: A wave in which the medium moves back and forth in the same direction as the wave.

crest: The highest point on a transverse wave.

diffraction: The bending of waves around an object.

electromagnetic wave: A wave that does not require a medium to travel, for example, it can travel through a vacuum. Also called an EM wave.

energy: The capacity to do work.

frequency: How many waves go past a point in one second. Measured in hertz (Hz).

mechanical wave: A wave that requires a medium to travel.

rarefaction : When the particles of a longitudinal wave are far apart.

reflection: When a wave bounces off a surface.

refraction: When a wave bends.

transverse wave: A wave in which the medium moves at right angles to the direction of the wave.

trough: The lowest point on a transverse wave.

wave: A disturbance that carries energy from one place to another.

wavelength: Distance between one point on a wave and the exact same place on the next wave.

### Agenda:

Good Morning All! Class is canceled today and Wednesday. Your unit 8 should be done. Thank you for those who sought out help over the weekend! The test for Unit 8 is still this WEDNESDAY!!!!!! It will just be virtual. The window for the test is 10AM – 2PM. Be aware!!!

Resources:

Physical Science B – Unit 8 (Mr. Tyler Version)

Key Topics Today:

• Continental Drift and Plate Tectonics
• Seismic Waves
• Sound Waves
• Light
•  Light Reflections/Rarefaction