Sound Travels Through Materials

Question 1

A student uses a string telephone made of two paper cups connected by a tightly stretched string. Which explanation correctly describes how the sound from the speaker’s voice reaches the listener’s ear?

Accepted Answer

The speaker’s voice makes the string vibrate, and those vibrations travel through the solid string to the other cup.

Answer

Sound can travel through a vacuum, so the string telephone would work even in space.

Answer

The sound travels through water that is inside the string, allowing it to reach the other cup.

Answer

The speaker’s voice creates sound waves that travel through the air inside the cups, so the string is not needed.

Question 2

A researcher puts a tiny speaker inside a clear glass jar. In the first test she leaves the air inside the jar untouched. In the second test she uses a pump to suck out all the air, making a vacuum inside the jar. She turns the speaker on at the same volume in both tests. Which test will let a child standing outside the jar hear the speaker, and why?

Accepted Answer

The first test, because the speaker’s vibrations travel through the air inside the jar to the glass and then into the air outside.

Answer

The first test, because sound can travel through the glass walls even when there is no air inside.

Answer

The second test, because sound waves can move through a vacuum just like they move through air.

Answer

The second test, because the glass lets the vibrations move directly through the empty space inside the jar.

Question 3

A string telephone is made by stretching a long piece of string between two paper cups. When a person speaks into one cup, the other person can hear the sound. Which statement best explains how the sound reaches the second cup?

Accepted Answer

The speaker’s voice makes the string vibrate, and the vibrations travel through the solid string to the second cup, where they cause the air inside the cup to vibrate and reach the ear.

Answer

The speaker’s voice sends sound vibrations through a vacuum between the cups, allowing the sound to be heard.

Answer

The speaker’s voice causes the paper cups to vibrate, and the vibrations travel directly through the cups without using the string.

Answer

The speaker’s voice creates sound waves that travel through the air inside the string telephone, reaching the second cup.

Try three questions

A student uses a string telephone made of two paper cups connected by a tightly stretched string. Which explanation correctly describes how the sound from the speaker’s voice reaches the listener’s ear?

A string telephone is made by stretching a long piece of string between two paper cups. When a person speaks into one cup, the other person can hear the sound. Which statement best explains how the sound reaches the second cup?

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