Stage 7 Science: Sound Waves 3

What is the medium through which sound waves travel?

• Solids, liquids, and gases

• Only gases

• Only liquids

• Only solids

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Remembering

Why can't sound travel in a vacuum?

• There are no particles to vibrate

• Sound waves are too weak

• Vacuum absorbs sound

• Sound needs light to travel

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Understanding

What would happen if you put an electric bell in a vacuum jar?

• You can see it vibrate but not hear it

• You can hear it but not see it vibrate

• You can neither see nor hear it

• You can both see and hear it

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Applying

Sound waves move the same way in gases, liquids, and ___.

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Remembering

A vacuum is a space where there are no ___.

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Understanding

To hear a sound, there must be a vibration and a ___.

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Applying

Sound waves cannot travel in a ___ because there are no particles to vibrate.

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Remembering

Which of these can sound travel through?

Select all the correct answers. Write the letters

• solid

• liquid

• gas

• vacuum

The Moon has no atmosphere. People who went to the Moon wore suits that contained air. The people who went to the Moon worked close together. They did work such as hammering and digging.

Explain why the people doing this work could not hear it happening.

• The Moon has a thin atmosphere that allows sound to travel.
• The suits amplified the sound of the work being done.
• The astronauts could hear the work because sound travels faster in space.
• The astronauts could not hear the work happening because there is no atmosphere on the Moon for sound to travel through.

Science fiction films are made in studios on Earth. These films often show explosions in space. There is usually a loud bang when the explosion happens. Explain whether you would really hear an explosion in space.

• No, you would not hear an explosion in space.
• Yes, you would hear a faint sound in space.
• Sound travels faster in space than on Earth.
• Explosions in space create a loud echo.