Ch 15 Lab Summaries…
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- The length of a string represents _____ of a wavelength of the fundamental frequency.
To find the whole wavelength you would ______.
- Draw the standing wave created by the string below.
- If you increase the tension on the string, the pitch ______. Explain why:
- If you increase the length of the string, the pitch ______. Explain why:
- The length of an open tube represents _____ of a wavelength of the fundamental
frequency. To find the whole wavelength you would ______.
- The length of a closed tube represents _____ of a wavelength of the fundamental
frequency. To find the whole wavelength you would ______.
- Draw the standing waves created by the open and closed tubes below.
How can you tell the waves from a voice, instrument or tuning fork?
- Calculate the frequency of each wave. Show your work.
- Top ______
- Bottom: ______
- To the right are two waves. Which one (top or bottom) is the highest sound? Explain.
- Which one (top or bottom) is the loudest sound? Explain.
- What created these sounds, a voice, an instrument or a tuning fork?Explain.
- To the right are two instruments playing same note. How canyou tellthey are instruments not tuning forks?
- How can you tell they are playing the same note?
- If they are playing the same note, why do they look different?
- Define these two words and tell how they apply to this lab:
- Resonance
- Harmonics
How do light rays reflect off of surfaces?(Reflection Lab)
- Reflection is when light ______off a surface and comes back.
- The angle light comes in at is called the ______and this is equal numerically to the angle it bounces back at, which is called the ______.
- This is known as the ______of Reflection.
- Label the following on this diagram: incident ray
reflected ray
mirror
angle of incidence
angle of reflection
normal.
- On the diagram above, draw a line coming in at 27o. Draw the line (ray) going out.
- Light rays reflect in ______off a smooth surface and you get a clear image.
- Light rays reflect and ______off a rough surface and you get no image.
- Just for fun (not on the test), show light rays and describe the images for
- Plane mirror:images look:
- Convex mirror: images look:
- Concave mirror: images look:
Can you see waves bend? Refraction Lab
- Refraction is when light ______as it goes from one medium to another.
- Explain why it does this.
- The amount that light bendsis known as the ______and is a physical property of the material. That means it’s the ______for that material, regardless of the incident angle but ______for a different material.
- Label the following on this diagram:incident ray
refracted ray
normal
angle of incidence
angle of refraction
- As light waves go from a less dense to denser medium (e.g. air to glass), they
______in speed and bend ______the normal. As they go from a denser to less dense medium (e.g. glass to air), they ______in speed and bend ______the normal.
- Is the material the square is made out of more or less dense than the material around it? Explain.
- On the diagram above, draw the ray as it exits the material. The normal has been drawn for you.
- Just for fun (not on the test), show light rays and describe the images for
- Convex lens:
- images look:
- Concave lens:
- images look:
Ch 15 Lab Summaries…
?
- The length of a string represents _1/2_ of a wavelength of the fundamental frequency. To find the whole wavelength you would _multiply by 2_.
- Draw the standing wave created by the string below.
- If you increase the tension on the string, the pitch _increases_. Explain why:
You’ve changed the medium, it vibrates faster (frequency
increases).
- If you increase the length of the string, the pitch _decreases _. Explain why:
You’ve increased the wavelength, so frequency decreases
- The length of an open tube represents _1/2_ of a wavelength of the fundamental
frequency. To find the whole wavelength you would _multiply by 2_.
- The length of a closed tube represents _1/4_ of a wavelength of the fundamental
frequency. To find the whole wavelength you would _multiply by 4_.
- Draw the standing waves created by the open and closed tubes below.
How can you tell the waves from a voice, instrument or tuning fork?
- Calculate the frequency of each wave. Show your work.
- Top: __24 waves in .05 sec = 480 Hz_
- Bottom: _5.8 waves in .02 sec = 290 Hz__
- To the right are two waves. Which one (top or bottom) is the highest sound? Explain.
Top…higher frequency
- Which one (top or bottom) is the loudest sound? Explain.
Both the same … same amplitude
- What created these sounds, a voice, guitar, saxophone or tuning fork? Explain.
Tuning fork…no wubbady wubbadies (interference). Only 1 substance is vibrating.
- To the right are two instruments playing same note. How can you tell they are instruments not tuning forks?
wubbady wubbadies (interference) because more than 1 substance is vibrating.
- How can you tell they are playing the same note?
Same frequency…hard to see clear waves, but can see repeating pattern. There are 18 of them for each. The top is a trumpet, the bottom is a violin.
- If they are playing the same note, why do they look different?
They make the same fundamental frequency (note) but other parts vibrate, too (resonance) and those other waves (harmonics) give each instrument/voice it’s unique sound.
- Define these two words and tell how they apply to this lab:
- Resonance: when 1 thing vibrates it causes others to vibrate, too. When a string on an instrument vibrates, it causes other strings, wood, etc to vibrate, too.
- Harmonics: Other frequencies something vibrates at besides the fundamental frequency, caused by resonance, gives the interference (wubbady wubbadies) to the waves above.
How do light rays reflect off of surfaces? (Reflection Lab)
- Reflection is when light __bounces______off a surface and comes back
- The angle light comes in at is called the _angle_ __of__ __incidence__ and this is equal numerically to the angle it bounces back at, which is called the _angle_ __of__ __reflection__
- This is known as the __Law_ of Reflection.
- Label the following on this diagram: A. incident ray
B. reflected ray
C. mirror
D. angle of incidence
E. angle of reflection
F. normal.
- On the diagram above, draw a line coming in at 27o. Draw the line (ray) going out.
- Light rays reflect in __one__ __direction_ off a smooth surface and you get a clear image.
- Light rays reflect and __scatter__ off a rough surface and you get no image.
- Just for fun (not on the test), show light rays and describe the images for
- Plane mirror:images look:
the same, but left is right
- Convex mirror: images look:
smaller, right side up
- Concave mirror: images look:
big, right side up (close), upside down (far)
Can you see waves bend? Refraction Lab
- Refraction is when light __bends____ as it goes from one medium to another.
- Explain why it does this.
It changes speed as it goes from one medium to another
- The amount that light bends is known as the _index_ _of__ __refraction__ and is a physical property of the material. That means it’s the __same__ for that material, regardless of the incident angle but _different_ for a different material.
- Label the following on this diagram:A. incident ray
B. refracted ray
C. normal
D. angle of incidence
E. angle of refraction
- As light waves go from a less dense to denser medium (e.g. air to glass), they
__decrease_ in speed and bend __toward_ the normal. As they go from a denser to less dense medium (e.g. glass to air), they __increase_ in speed and bend _away from__ the normal.
- Is the material the square is made out of more or less dense than the material around it? Explain.
More dense…the ray bends towards the normal, because the wave slows down.
- On the diagram above, draw the ray as it exits the material. The normal has been drawn for you.
The ray will bend away from the normal, because the wave speeds up going from a dense to less dense material.
- Just for fun (not on the test), show light rays and describe the images for
- Convex lens:
- images look:big, right side up (close), upside down (far)
- Concave lens:
- images look:small, right side up