Unit 3 Waves and Light
Lesson 1 Waves
• A wave is the transmission of energy through matter or
empty space.
• There are several kinds of waves: light, sound, ocean,
micro, and radio
• Waves travel from a source and move away from that
source
• Energy transmits through materials through vibrations.
Vibrations are a back and forth motion that constantly
repeats within a set of objects (particles). For instance,
a vibrating particle passes its energy to a second
nearby particle causing it to vibrate like itself.
Unit 3 Waves and Light
Lesson 1 Waves
• When you hear the word wave, what do you
think of?
Unit 3 Waves and Light
Lesson 1 Waves
• Classification of Waves:
1. Mechanical waves: waves that need to travel
through a medium (solids, liquids, or gases)
- examples would be sound
(does not travel through a vacuum) and ocean
waves
2. Electromagnetic waves: waves that do not
need a medium in order to transmit
- examples are radiation, UV
light, x-rays, gamma rays, microwaves, infrared
waves, and visible light
Unit 3 Waves and Light
Lesson 1 Waves
• Types of Waves
1. Transverse waves – waves that have
particles that move up and down in a
perpendicular (across) direction.
-parts: crest (highest
point) and trough (lowest point)
-example: electromagnetic
waves
Unit 3 Waves and Light
Lesson 1 Waves
• Types of Waves (con’t)
2. Longitudinal waves – wave where particles
move back and forth along the direction of the
wave within a given medium
- parts: compression
(crunched together) and rarefaction (spread
apart)
- examples: sound
waves
Unit 3 Waves and Light
Lesson 1 Waves
• Types of Waves (con’t)
3. Surface waves = move in circles: particles
move forward at the crest and backwards at the
trough
-parts= transverse + longitudinal waves