1. Ch. 4 Waves, Sound, Light Waves Think of the wave in a stadium.
A disturbance that moves through matter or space and carries energy
Matter does not move from place to place.
Energy transfers through the matter.
Think of the wave in a stadium.
The people (matter) do not change seats, but the energy travels around the stadium.

2. Compression Waves AKA: Longitudinal wave
A mechanical wave (through matter only)
Causes particles to move back and forth along the same direction in which the wave is moving.

3. Lesson 1 Sound Waves Sound Waves = Compression Waves
Cannot travel through empty space.
Mechanical waves
Travel fastest through solids, then liquids, then gases.
Travel fastest in warm
mediums.

4. Sound intensity Amount of energy carried by the wave.
Measured by the amplitude.

5. Amplitude The amount of energy that a wave carries.
Tighter compressions on a compression wave equal greater energy and louder sound.

6. Compression Wave Wavelength

7. Frequency and Pitch. Frequency Pitch
The number of wavelengths (compressions) that pass a point each second
Pitch
The human perception of the frequency of sound.
Sounds with a low pitch have a low frequency.
Sounds with a high pitch have a high frequency.

8. The Human Ear Outer Ear Visible ear and ear canal.
Compression wave funnel
Cup your hand around your ear?

9. Middle Ear Sound amplifier Eardrum 3 smallest bones in the body
Tiny membrane that acts like a drumhead and vibrates with the compression waves.
3 smallest bones in the body
Hammer - Malleus
Anvil - Incus
Stirrup - Stapes

10. Inner ear The sound converter
The amplified compression waves travel from the stirrup to the cochlea.
Cochlea
Fluid filled
Snail shell shaped organ lined with billions of tiny hair like structures.
convert compression waves into nerve impulses.
Nerve impulses travel through auditory nerve to brain where they are interpreted as sound.
Semi Circular Canals: Acts as device to keep a human balanced.

11. The Human Ear

12. Sound reflection Reverberations Echolocation Echoes
Sounds that reflect
Echolocation
Process of locating objects by bouncing sounds off of them.
Bats, Dolphins, Whales

13. Wave Speed Electromagnetic waves: light waves Travel fastest: Space
Air (gas)
Water
Transparent solid
Mechanical Waves: compression/transverse
Solids
Air
Do not travel through space

14. Section 2 Light Waves

15. Transverse waves A mechanical wave (Can only move through matter)
Causes particles to move back and forth at right angles to the direction of the wave motion.
Rock in a pond!
crest
trough

16. Electromagnetic Waves
Can travel through empty space, gases, liquids, and solids.
Two Transverse Waves: examples
Light waves
X rays
Wi-Fi
AM,FM radio signals
Remote controls
Contain electric transverse wave and a magnetic transverse wave

17. Electromagnetic Wave

18. Amplitude: brightness, energy, intensity!

19. Wavelength
The distance between two like points on a wave.
wavelength

20. Frequency The number of wavelengths that pass a point each second.
Count the crests or troughs
Count the compressions or rarefactions
1 second

21. Frequency equals……. 6 wavelengths / second 6 λ / s 6 hertz 6 Hz

22. Light Waves are…..
Able to travel up to 185,000 miles/s in empty space.
Able to travel from the sun to earth (150 million km) in 8 minutes.
Able to travel the fastest in empty space and the slowest in solids. (glass)

23. The electromagnetic spectrum
Increasing Energy
Decreasing wavelength

24. ROY G BIV R
O Y G B I V

26. E.M. Waves and examples Radio waves AM, FM, cell signals Microwaves
Wi-Fi, Microwave ovens, gps signals, satellite signals
Infrared waves
Heat producing bodies, remote controls
Visible Light
ROY G BIV
Ultraviolet waves
UV rays, bacteria killing lights
X-rays
Gamma Rays
Nuclear bombs, sun’s energy

27. Interaction of Light and Matter
Transmission
Light traveling through a material
Transparent
Almost all light travels through for a clear image
Translucent
Most light travels through, blurry image
Opaque
Light waves do not pass through
Reflection
Light bouncing off a material
Absorption
Light changing to heat

28. Refraction
Waves travel at different speeds depending on the properties of the material they are traveling through.
Causes the wave to change direction.

29. Law of Reflection
The angle of the incoming wave will equal the angle of the outgoing wave.
normal

30. Diffraction The bending of waves around an object.
Do shadows have crisp edges? If so, when?
Shadow of hand on desk?
Any light?

31. Diffraction: Look at the edges!

32. Sct. 3 Mirrors, lenses, the eye
2 major types of mirrors/lenses
Concave
The surface is curved inward

33. Concave lenses One or both surfaces are curved inward
Used to spread the light waves apart

34. Convex
Surfaces that are curved outward

35. Convex lens
One or both sides are curved outward

36. The human eye.

37. How we see! Light waves reflect off of an object.
Reflected light waves enter eye through cornea.
Transparent convex layer of outer eye.
Waves pass through the pupil.
Opening in the eye controlled by the iris.
Waves then pass through the lens.
Flexible convex lens that changes shape to allow you to focus on near and far objects.
Lens focuses waves on retina.
Back wall of the eye.

38. Retina Contains over a hundred million light sensitive cells. Rods
Sensitive to dim light
Help us to see in darkness.
Cones
Enable us to see colors.
3 types
Red/yellow
Green/yellow
Blue/violet

39. Image of rods and cones in retina.

40. Let’s see.

41. Nearsighted vs. Farsighted.
Cannot see objects far away.
Image focused to NEAR to the lens.
Farsighted
Cannot see object that are close.
Image focused to FAR from the lens.

44. Color in our world
The color of the objects you see represents the wavelength that reflects.
white light