Unit 4: Waves, Sound, and Color

___________ - repetitive back and forth motions

Waves – a traveling ________ that carries _______ from one location to another.

Think about waves like ________ in a pond.

Mechanical Waves

_______ waves – must travel through _______.

Matter = ________, ________, and _______. _________ travel through a vacuum.

Electromagnetic Waves

___________ waves – can travel through transparent material and vacuums.

Example? __________.

Longitudinal Waves: compression waves

Transverse Waves: sinusoidal waves

Wave Terms!

_________ (λ) - the distance between two identical points on two consecutive waves.

__________(f) – The number of oscillations, vibrations, or waves passing a reference point per second. We measure this in ________ (Hz).

__________ (T) – The time for one single oscillation, vibration, or wave.

______ _____ (c) – How fast a wave travels.

Note: Frequency and wavelength are inversely proportional to each other.

Greater frequency shorter wavelength

Lower frequency greater wavelength

Mechanical Waves Energy begins moving via ________ or ________

through an elastic source. ________ medium is needed. Energy transfers ______ from the source. It temporarily ________ the medium. Medium _______ ______ to the way it was after

the wave has passed. The ______ of _______ (amplitude) weakens

the ________ it gets from the disturbance.

Stretch the spring using WORK against resistance, Create PE. If released, the spring will “snap back” to restore its original shape

Rest (equilibrium position): No motion, the shape of the spring is maintained by its restoring force.

Compress the spring using WORK against resistance, Create PE. If released, the spring will “snap back” to restore its original shape.

Energy relationship of a spring

Stretch the spring to induce PE, then release!

Compressed position: v = 0, PE = 100%. Instantaneous change in direction.

Passing through the rest position (equilibrium position): v = max, PE = 0

Passing through the rest position (equilibrium position): v = max, PE = 0

Passing through the rest position (equilibrium position): v = max, PE = 0

Stretched position: v = 0, PE = 100%. Instantaneous change in direction

Simple harmonic motion of a spring

Rest positionv = max, PE = 0

Max h: v = 0, PE = maxInstantaneous change in direction

Simple harmonic motion of a pendulum

Max h: v = 0, PE = maxInstantaneous change in direction

Simple harmonic motion of a standing wave (e.g., plucked string)

Rest position: v = max, PE = 0

Max displacement: v = 0, PE = max

Max displacement: v = 0, PE = max

Air molecules become compressed at the condensations (increased pressure) and become diffused at the rarefactions (decreased pressure).

Human hearing range: ____________ hertz Sound travels fastest through ______, and

slowest through ________.

Why we care about waves for sound _________ - the maximum displacement of the

wave (or height of it). Why we care: _________ is the _________ of the

sound. _________ - places where the wave has stopped

and is sitting at equilibrium. Why we care: _________ or ________ in the

music. Pause between notes. Compressions = __________ Rarefactions = __________ or _________.

________ - when a wave bounces off of something back toward you.

Why we care: This is how we _________ sound.

________ - when a wave is bent Why we care: this is what causes an

_______.

Refraction tendencies As sound waves pass through an air-solid boundary• Air Glass: Speed up and change direction• Glass Air: Slow down and change direction

As sound waves pass through cold air-warm air boundary• Cold air warm air: Speed up and change direction• Warm air cold air: Slow down and change direction

As sound waves pass through two different solids with different densities• More dense Less dense: Slow down and change direction• Less dense More dense: Speed up and change direction

Intencity of sound is measured in _______. Anything over ______ decibels (dB) can

cause permanent damage to your ears. Resonance – the __________ of sound left

after the initial cause has been hit.

Beat Beat Beat Beat

Noise Noise Noise Noise

Wave 1

Wave 2

Wave functions are additive. Wave 1 and Wave 2 have different frequencies and wavelengths. When Wave 1 and Wave 2 interact, the sum of the waves will produce noise and beats. Noise is where individual waves are out of phase, thus produce non-harmonic multiple tones. Beat is where individual waves are in phase and the amplitudes combine to produce a harmonic pure tone.

Wavelengths and Sound

Wavelengths cause “notes.” The ________ the wavelength, the _______

the sound. The _______ the wavelength, the _______

the sound.

Doppler Effect

The seeming change in ________ because of the object’s or your ________.

http://www.youtube.com/watch?v=z0EaoilzgGE

Sound travels at the same _______, but the objects or you ________.

LIGHT

Light is ________________ waves, NOT longitudinal/compression.

Why we see

Our eyes have two main types of receptors: _________ and _________.

_________ - measure “lightness,” “darkness,” and register motion.

_________ - detect color.

Our cones have ________ color receptors in them. These are the three primary colors IN LIGHT.

_________ _________ _________

This is our color spectrum. We see all of this because of those 3 color cones.

Other animals have different cones, and can see other colors.

Animal Color Trivia Dogs only have _______ color cones, so they

can see shades of green, blue, and some yellows.

Nocternal hunting animals can see into the _________ light spectrum.

Bees can see into the ultraviolet spectrum, and scientists call that “bee yellow.”

Butterflies have 5 different color cones in their compound eyes.

The mantis shrimp has 16.

More facts about the mantis shrimp

http://theoatmeal.com/comics/mantis_shrimp

http://www.youtube.com/watch?v=F5FEj9U-CJM

Back to light Light _________ and ___________. ___________ - we see reflection/color. ___________ - Bends light. This is why we

don’t see things straight on in water.

When light bends through mist, it’s bending over and over again through thousands of _________ ____________.

Every time it goes through a droplet, the light __________.

This makes us see the full ________ ________.

In other words: a ___________.

We see an object’s color because that’s the only color that object is ________. All the other color it absorbs.

WHITE – ______ color wavelengths reflected.

BLACK – absence of color. __________ is reflected, EVERYTHING is absorbed.

Color Wheels

The Primary colors of light are red, blue, and green:

The primary colors when painting are red, blue, and yellow.

For painting: Primary colors are ______, ________, _________.

Secondary colors are what they mix together to make: _________, ________, __________.

Complementary colors are colors __________ on the color wheel. When mixed they make _________.