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What can a microphone hear beneath the sea?

A microphone beneath the sea can reveal activity that a person watching the surface would miss. Hydrophones record animal sounds alongside other underwater noise, giving researchers another way to investigate marine life. But a recording is not a head count: one animal may call repeatedly, while another remains silent. Detection depends on both the sound and the listening conditions.

3–7 min

Questions you could explore

  • How could you tell many calls from one animal apart from calls made by many animals?
  • How do a hydrophone's position and background noise affect which underwater sounds it records?

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Nature and biology

How does a honey bee dance give directions?

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How does a honey bee dance give directions?

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How can an octopus change color so quickly?

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How can an octopus change color so quickly?

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Nature and biology

Finding prey through returning echoes

An echolocating bat uses the delay and character of returning sound to follow a target. Its calls can change as it approaches prey, connecting the sound it sends with the information it needs next.

3–5 min

Finding prey through returning echoes

Nature and biology3–5 minAn echolocating bat uses the delay and character of returning sound to follow a target. Its calls can change as it approaches prey, connecting the sound it sends with the information it needs next.

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