Topic: Wave speed in media

Pre-assessment

1. Sound waves travel at different speeds through different materials. Through which of the following materials will sound waves travel the fastest?

  1. A copper pipe
  2. B swimming pool
  3. C air on a cold day
  4. D sauna filled with steam

2. While Melinda was at the beach, she decided to go swimming. While she was in the water, she saw a motorboat in the distance. When Melinda put her head under the water, she discovered that the sound of the motorboat was louder. The next day, she asked her science teacher why this happened. What explanation did Melinda’s science teacher provide?

  1. A The motorboat moved closer to Melinda.
  2. B Sounds travel fastest through the air.
  3. C Sounds travel faster through liquids than through gases.
  4. D Melinda’s sense of hearing is better under water than on land.

Bending Pencil Demonstration Lab

Materials:

  • Large glass beaker
  • Small glass beaker that fits inside the larger one
/
  • Water
  • Cooking oil
  • Wood pencil

Investigation:

  1. Place the small drinking glass inside the large one.
  2. Fill both glasses with water and place the pencil into either glass.
  3. Sketch your observations.
  4. Repeat steps 2 and 3 with the following combinations of liquids:
  5. Oil in both glasses
  6. Oil in inner glass, water in outer glass
  7. Water in inner glass, oil in outer glass

Pencil
Location / Both with water / Both with oil / Oil in inner glass
Water in outer glass / Water in inner glass
Oil in outer glass
Inner
Glass
Outer
Glass

Post-Assessment

____1Sound waves and light waves both change speed as each passes from the air to water. Which statement accurately describes the changes in speed?

  1. The light waves will speed up, but the sound waves will slow down.
  2. The sound will speed up, but the light waves will slow down.
  3. Both light waves and sound waves will speed up.
  4. Both light waves and sound waves will slow down.

_____2. While Melinda was at the beach, she decided to go swimming. While she was in the water, she saw a motorboat in the distance. When Melinda put her head under the water, she discovered that the sound of the motorboat was louder. The next day, she asked her science teacher why this happened. What explanation did Melinda’s science teacher provide?

  1. Sounds travel faster through liquids than through gases.
  2. The motorboat moved closer to Melinda.
  3. Sounds travel fastest through the air.
  4. Melinda’s sense of hearing is better under water than on land.

3. Describe why the speeds of light and sound are affected oppositely by media.

______

______

______

4. Complete the Venn Diagram for the speeds of light and sound.

Speed of Light Speed of Sound

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