Video and lesson investigations on the topic of echoes. Key concepts include:
- When sound bounces back towards us, we are getting a reflection (echo) of the sound that was traveling away from us.
- Flat hard and smooth surfaces reflect sound well.
- Echoes can travel through water.
- Echoes can be used to detect where things are.
- The longer an echo takes to return, the further away the reflecting surface is. Sound waves rebound in much the same way that light waves reflect off a mirror.
- We hear many sounds because of reflections, but echoes occur only when the sound bounces back from a surface which is some distance away and returns to our ears.
- Animals such as bats, dolphins, and some whales use echoes as the way of gathering information.