1. Wave Properties

2. Waves In General: Sound speeds in different mediums Air (0 degrees)
Water
1500 m/s
Iron
4400 m/s
Glass
5100 m/s
Waves are energy traveling through a “medium” (solid, liquid or gas material)
Properties of waves depend on elasticity of the medium:
As you can see, sound travels
at different speeds depending
on the medium
Think: Why would waves
move through solids faster
than a gas like “air”?

3. Sound Travel in “Space”:
So if the astronauts communications device fails,
can they take their helmets off (don’t worry about the
whole “breathing” thing here) and just talk?
If there isn’t enough atoms (“air”) out there,
can the sound energy actual travel anywhere?
Think: What is missing for the energy of
sound to travel between them?
So can there be any sounds out there at all?

4. Properties of Waves:
They may not look like much, but waves have several features that we
use to describe what result the energy will have:

5. Wavelength:
Wavelength: The distance between any point on a wave and the equivalent point on the next phase. Literally, the length of the wave.
It is either the distance between
two different tops of waves
Or the distance between
two different bottoms of waves,
either way, it will be the same!

6. Wavelength:
Wavelength: The distance between any point on a wave and the equivalent point on the next phase. Literally, the length of the wave.

7. The Amplitude is from crest or trough, to equilibrium or rest position
Amplitude: The strength or power of a wave signal. The "height" of a wave when viewed as a graph.
The Amplitude is from crest or trough, to equilibrium or rest position

8. Amplitude
Amplitude: The strength or power of a wave signal. The "height" of a wave when viewed as a graph.
(Also note that high amplitude = high energy.)
A shape
If I wanted to increase the amplitude, I simply increase its height.

9. Amplitude Amplitude = Loudness = Volume
Higher amplitudes are interpreted as a higher volume, hence the name "amplifier" for a device which increases amplitude.

10. How we sense Amplitude = Loudness
Higher amplitudes are interpreted as a higher volume, hence the name "amplifier" (or “amp’s”) for a device which increases amplitude.

11. Frequency:
Frequency: The number of times the wavelength occurs in one second. (Like waves per second)
The faster the sound source vibrates, the faster the wave and the “higher” the frequency.
1 second
Low
High

12. How Frequency Affects Sound:
How we sense Frequency = “Pitch”
Higher frequencies are interpreted by our brain as a higher pitch. For example; when you sing in a high-pitched voice you are forcing your vocal chords to vibrate quickly.
(Also note that high frequency = high energy.)
“High” note = High Frequency
“Low” note = Low Frequency
Our ears are sensitive to sound energy. We perceive a high
frequency as a high pitched note; a low frequency as a low pitched note.
Notice: Did the Amplitude change when we changed the frequency?

13. “Light” Spectrum: A graph that shows the different frequencies of light waves and the resulting types of light and colors.
Light Frequency = Type of light and color
Higher frequencies are interpreted as different types light. For example; a higher frequency can make a darker color.
Radio | Micro | Infra Red | Visible Light | UV | X-Ray | Gamma
Notice that low Frequencies
make radio, micro, and Infrared
waves of energy
Higher Frequencies
make Ultraviolet, X ray, and Gamma
waves of energy
Also different Frequencies
make colors. This is the only
type of light Humans can see.
Lastly: Notice that all
These Waves have the
same amplitude!

14. So what is White Light?
White Light is actually made up of many different colors – each color is made up of its own frequency and wavelength.
When you combine the colors together
it actually makes white light!
You can shine white light into a prism
and it separates it out into the mix of colors

15. Notice the white light coming in
Notice the split spectrum coming out.

16. (Faster than most jets)
Wave Speed:
Average Wave Speeds: can vary depending on the type of energy
Light = 3.0x108 m/s
Sound ≈ 340 m/s
(Faster than most jets)
Of course it still depends on what medium the Energy is travelling through!!!

17. Light travels faster than Sound!!!
Why we see the firework first – then hear it after?
Light travels faster than Sound!!!

18. Hammering It takes longer for the sound energy
To reach your ear than for the light
Energy to reach your eye!
That’s why we can see something
before we can hear it!

19. If the Wave propagated out on a separate 2D plane, I wouldn’t see it.
Wave hitting my eye – I can see it!
If waves propagated in only 2D like waves on a pond, then if we moved the candle up a little higher we wouldn’t be able to see it.

20. Since waves propagate in 3D, we can see the light from this candle in all directions. Same thing applies with sound.

21. Wave motion is like an onion: Spreads out in all directions equally!
Think about it; is there any direction (up down, left, right…etc…)
that the sun DOESN’T shine it’s light and heat energy?
Intensity: The further out you go from the energy source, the less intense the wave is. The reason the farther out planets are “colder” is because they are farther from the source of the heat and light in our solar system.
EX: If you wanted to save your ears from the loudness of the speakers – scoot back!

22. In every direction equally at the same time!
Movement of Waves:
The layers of an onion, are a good representation of how waves look as they travel
In every direction equally at the same time!
HEY! I’ve got layers too!!!
The exception is “surface waves” (like wind generated ocean waves). They only travel on a “surface” (not up and down).

23. Common Instruments we use to sense light energy in our lives
Glasses
Telescope
MRI Machine
Satellite Dish

24. Common Instruments we use to sense waves in our lives
Hearing Aid
Microphone
Sonar
Stethoscope
Ultrasound