How Do Sound and Light Work?

Demonstrate that waves have energy and waves can transfer energy when they interact with matter


Sound
  1. Listen through all five “cup phones”. For each one:
    1. State the length of the cord
    2. How well you were able to hear another person through the phone?
  2. Which was easier to hear people through: the longer or the shorter phones? Why?
  3. Take a set of dominoes and set it up so that you have two parallel lines of dominoes: One line of dominoes should have the dominoes spaced very closely together and the other line should be as far apart as possible and still be able to knock the next one down. Then, race the two to see which one goes faster. Which is it?
  4. The two lines represent how sound moves through cold air and hot air. Which line represents which temperature of air? Why?
  5. Through which does sound move faster: cold or hot air?
Why?

For this assignment, you will be given one of the following questions to answer. You need to do the following:

  1. Research the answer to the question.
  2. Restate the answer in a way that you and your peers will understand.
  3. Make a drawing or sketch that represents this phenomenon.

The questions:

  • Why is the sky blue?
  • Why are clouds white?
  • Why are sunsets red?

Before getting started, you will fill out the “Know” and “Want to Know” columns of this KWL chart. You may not respond, “I don’t know,” “I want to know what it is,” etc. You must attempt to give a thoughtful response to each one. You can even include personal experiences.

Question Know Want to Know Learned
Why is the sky blue?
Why are clouds white?
Why are sunsets red?
Properties of Light
  1. Using a string or spring, define:
    1. Frequency
    2. Wave Length
  2. What is the wave length of at least three different types of electromagnetic radiation?
  3. Even though we can see visible light, we cannot actually see the size of the waves because they are too small. But if we multiply the wavelengths by 10 million, then we can see the wavelengths in centimeters. Get six colored pencils and a piece of plain white paper to represent all of the wavelengths of visible light using the information below:
    1. Red – 7.0 cm (actually 7.0 nm)
    2. Orange – 6.0 cm (6.0 nm)
    3. Yellow – 5.7 cm (5.7 nm)
    4. Green – 5.3 cm (5.3 nm)
    5. Blue – 4.7 cm (4.7 nm)
    6. Violet – 4.0 cm (4.0 nm)
  4. From #3, which wavelengths of light seem to have the most energy?
  5. Our sun’s spectrum peaks at about 5.5 nm. If you were going to paint something to seem as bright as possible, what color would you paint it?
  6. Get a set of lenses. Which is convex and which is concave? How can you tell?
  7. Get a mirror. Describe the image that you see in the convex side and the image that you see in the concave side.
  8. Get two polarizing filters. Describe how you can let all of the light through and how you can block out the light. Experiment with looking at monitors and the television. Explain what the polarizing filters are doing! You can use a sketch or drawing to help you explain.
Optics
  1. Define converging and diverging lenses.
  2. Get a set of three lenses / mirrors. For each lens or mirror, state:
    1. Whether it’s converging or diverging
    2. Where the light is coming from and going
  3. Define:
    1. Principal axis
    2. Focal point
    3. Focal length
  4. Get an optics set. With the optics set, try and focus the candle light on the index card.
    1. What do you need to do to make the candle light focus into a single point?
    2. What do you need to do to make the candle light appear upside-down on the card?
Refraction & Reflection
  1. Find three examples at home where light is bending (refracting). Keep in mind that glass, water, and lenses all cause light to bend. For each one, determine:
    1. If it’s acting as a convex (brings light together) or concave lens (spreads light out)
    2. How well it allows you to see objects on the other side
  2. Find two examples of mirrors. For each mirror, explain how well it is reflecting the light.
  3. With one of the mirrors, do the following experiment. Stand one foot away from the mirror and measure how much of your body you can see in the mirror. If you stand ten feet back, do you think you’ll be able to see more, less or the same amount of your body? Try it and report the results!
Wave Properties
  1. What is the lowest frequency electromagnetic wave that has been detected?
  2. How many Hz is typical AM radio?
  3. What is the range of frequencies of typical FM radio?
  4. What color is low-frequency visible light?
  5. What color is high-frequency visible light?
  6. What sort of wavelength does a low frequency produce? A high frequency?
  7. Do different types of light travel at different speeds?
  8. Choose your two favorite FM radio stations and answer:
Radio Station Name Frequency (MHz) Wavelength (300 / Frequency) Objects in Room
  1. What are their frequencies (f, in MHz)?
  2. The speed of all electromagnetic radiation is about 300 million meters per second (velocity). Calculate the length of the wave, represented by the lambda (): 
  3. Using a meter stick, what objects are also about as long as the wavelengths of your favorite radio stations?
  1. Describe, in your own words, the difference between transverse and longitudinal waves.
  2. Does sound travel in transverse or longitudinal waves?
  3. What do we call the frequency of the sound wave produced?
  4. What substances can produce sound?
  5. About how fast does sound travel in air at room temperature?
  6. About how many times faster is the speed of light than the speed of sound?
  7. Why can you yell further on a cold day than on a warm day?
Electromagnetic Radiation
  1. What is the lowest frequency electromagnetic wave that has been detected?
  2. How many Hz is typical AM radio?
  3. What is the range of frequencies of typical FM radio?
  4. What color is low-frequency visible light?
  5. What color is high-frequency visible light?
  6. What sort of wavelength does a low frequency produce? A high frequency?
  7. Do different types of light travel at different speeds?
  8. Choose your two favorite FM radio stations and answer:
Radio Station Name Frequency (MHz) Wavelength (300 / Frequency) Objects in Room
  1. What are their frequencies (f, in MHz)?
  2. The speed of all electromagnetic radiation is about 300 million meters per second (velocity). Calculate the length of the wave, represented by the lambda (): 
  3. Using a meter stick, what objects are also about as long as the wavelengths of your favorite radio stations?