Unit 4: Waves, Sound, and Color

1. Unit 4: Waves, Sound, and Color

2. ___________ - repetitive back and forth motions • Waves – a traveling ________ that carries _______ from one location to another. • Think about waves like ________ in a pond.

3. Mechanical Waves • _______ waves – must travel through _______. • Matter = ________, ________, and _______. • _________ travel through a vacuum.

4. Electromagnetic Waves • ___________ waves – can travel through transparent material and vacuums. • Example? __________.

5. Longitudinal Waves: compression waves Transverse Waves: sinusoidal waves

6. 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.

7. Note: Frequency and wavelength are inversely proportional to each other. Greater frequency  shorter wavelength Lower frequency  greater wavelength

8. 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.

9. Energy relationship of a spring Rest (equilibrium position): No motion, the shape of the spring is maintained by its restoring force. Stretch the spring using WORK against resistance, Create PE. If released, the spring will “snap back” to restore its original shape Compress the spring using WORK against resistance, Create PE. If released, the spring will “snap back” to restore its original shape.

10. Simple harmonic motion of a spring Stretch the spring to induce PE, then release! Passing through the rest position (equilibrium position): v = max, PE = 0 Compressed position: v = 0, PE = 100%. Instantaneous change in direction. Passing through the rest position (equilibrium position): v = max, PE = 0 Stretched position: v = 0, PE = 100%. Instantaneous change in direction Passing through the rest position (equilibrium position): v = max, PE = 0

11. Simple harmonic motion of a pendulum Max h: v = 0, PE = max Instantaneous change in direction Max h: v = 0, PE = max Instantaneous change in direction Rest position v = max, PE = 0

12. Simple harmonic motion of a standing wave (e.g., plucked string) Max displacement: v = 0, PE = max Rest position: v = max, PE = 0 Max displacement: v = 0, PE = max

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

14. Human hearing range: ____________ hertz • Sound travels fastest through ______, and slowest through ________.

15. 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 _________.

16. ________ - 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 _______.

17. 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

18. 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.

19. Wave 1 Wave 2 Noise Noise Noise Noise Beat Beat Beat Beat 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.

20. Wavelengths and Sound • Wavelengths cause “notes.” • The ________ the wavelength, the _______ the sound. • The _______ the wavelength, the _______ the sound.

21. 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 ________.

22. LIGHT • Light is ________________ waves, NOT longitudinal/compression.

23. Why we see • Our eyes have two main types of receptors: _________ and _________. • _________ - measure “lightness,” “darkness,” and register motion. • _________ - detect color.

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

25. 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.

27. 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.

28. More facts about the mantis shrimp • http://theoatmeal.com/comics/mantis_shrimp • http://www.youtube.com/watch?v=F5FEj9U-CJM

29. Back to light • Light _________ and ___________. • ___________ - we see reflection/color. • ___________ - Bends light. This is why we don’t see things straight on in water.

30. 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 ___________.

31. 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.

32. Color Wheels • The Primary colors of light are red, blue, and green: • The primary colors when painting are red, blue, and yellow.

33. 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 _________.