What makes an echo?

1. 1

   Roo says

   When you shout, your voice spreads out through the air as a sound wave. If it hits something hard and flat, like a cliff, most of it bounces back. A moment later it reaches your ears again, and you hear your own voice. That's an echo!

   For ages 4–7
   Hear Roo

   Checked against Curious Kids: what makes an echo? (The Conversation)

2. 2

   Why don't I hear an echo in my bedroom?

   Sound takes time to travel to a wall and back. In a small room, the wall is so close that the sound comes back almost at once. It gets mixed up with your own voice, so you can't hear it on its own. Out here, the far-away cliff gives the echo time to come back clearly.

   For ages 6–9
   Hear Roo

   Checked against Curious Kids: what makes an echo? (The Conversation)

In Lil' Phil, reaching the bottom of this wonder earns a sticker for Roo's collection.

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