1. Ch9: Waves
2. Lesson 1:What are
Waves?
3. What are Waves?
waves
5. Disturbance that transfers energy from one place to
another without transferring matter
5. Floating on raft; friend cannon balls into pool, and you
start to bob up and down (no forward motion)
4. A Source of Energy
5. Waves transfer energy away from the original source
5. Raindrops falling on pond water, the flame of a candle
4. Energy Transfer
Recall Energy is the ability to cause change
5. Energy from the diver transfers to the water and the
wave move outward causing a wave
Fig 2 pg 308
5. Because waves do not carry matter, the raft stays in
the same place (ex in book)
4.
How Waves Transfer Energy
5. Force is exerted on the particles of water, and each
water particle transfers the energy to surrounding
water particles
3.
mechanical
Ex:Water waves, sound waves
medium
Ex: Solids, liquids and gases
Mechanical Waves
5. Wave that can travel only through matter
5. Material in which a wave can travel
4. Transverse Waves
5. Disturbance is perpendicular (┴)in which the wave
travels
Fig 3 pg309 Ex: Up/Down motion on a wave on rope
Positions on a wave
Rest position
5. Position before waves has occurred
Crest
5. Highest points on a transverse wave
transverse
5. Mate
Troughs
5. Lowest points on a transverse wave
4. Longitudinal Waves
Longitudinal
Fig 4 pg310
compression
rarefaction
5. Makes the particles in a medium move parallel ( // )to
the direction that the wave travels
5. Compression and rarefaction are displayed in
longitudinal waves
5. regions of wave where particles are close together
5. regions of wave where particles are farthest apart
4. Vibrations and Mechanical Waves
vibration
5. Up-and-down or back-and-forth motion
5. Vibrating objects are the sources of energy that
produce mechanical waves
One Wave per Vibration
5. Transverse: ex rope caused by up-and-down motion of
hand
5. Longitudinal: ex spring compression caused by backand-forth motion of hand
Vibrations Stop-Waves Go
5. Waves do not stop immediately after the energy (hand)
stops
3. Types of Mechanical Waves
4. Sound Waves
Need a medium
Travels best in solid, liquid, gas
5. Travel in solids, liquids and gas
5. Made up compression and rarefactions
4. Water Waves
5. Combination of transverse and longitudinal waves
5. Wind causes ocean surface currents
4. Seismic Waves
5. Cause earthquakes
5. Mechanical waves that travel within Earth and on its
surface
5. Can be longitudinal and transverse
5. Travel along cracks, called faults
3. Electromagnetic Waves
Does not require a medium
5. Wave that can travel through empty space (vacuum)
and through matter
Ex: Light (solar energy)
4. Types of Electromagnetic Waves
5. Radio waves, microwaves, infrared, visible light, UV
rays, X-rays, gamma rays
4. EM waves and objects
5. All objects give off EM waves, thermal energy
(infrared waves) can be emitted (humans) as well as
visible light (glowing metal)
4. EM waves from the Sun
5. Most energy is carried through infrared and visible
light (92%) and the remaining energy is from UV
radiation (7%)