Echo (sound ) Flashcards
What is an echo?
When a sound wave reflects off a surface.
What kinds of surfaces absorb sound?
Soft, pliable and thin material
e.g. sponge/foam/carpet/ cloth
Which types of surfaces are best at reflecting sound?
Flat, hard, smooth materials
What happens to the temperature of a surface that can absorb sound?
It increases because energy is being transferred to that surface.
What’s echolocation?
It is up a technique used by bats, dolphins and other animals to determine the location of objects using reflected sounds. This allows animals to navigate in complete darkness, hunt, and avoid obstacles that cannot be seen. It can also be used to identify friends or enemies or their prey.
How does echolocation work?
For example, if a bat sends out sound waves with its mouth or nose, the particles around it moves like an Mexican wave and hits the object, creature or place. When it hits the object the sound bounces back towards the bat and the bat knows where it is and can determine the distance from shape and size.
What’s the formula for echolocation?
DISTANCE= SPEED X TIME
Example….
4200m = 1400m/s X 35
Distance for travel = 2100m (because 4200/2 is 2100. 4200m is going there and back)
What happens if sounds overlaps.
When 2 of the same sound waves interact it’s louder ( because they add together). If they are different sound waves, they would cancel each other out.
What is it called when two sound waves overlap?
Superposition
Why is there less echoes in soundproof room?
Because the walls would probably be a surface that absorbs sound waves. This means that only the other objects in the room will be able to reflect it. But it the sound proof room is small then the objects will return the echo so fast it matches to what you are saying which makes you think that there is no echo.
Why does sound echo in an empty room?
If the room is empty, then there would be less objects then a full room, so the sound waves would not get absorbed by the rough surfaces. This means in a empty room the sound waves would just bounce off wall to wall.
The time between echoes is due to the speed of …..
Sound
The longer the time, the further away the source of reflection.
True or false.
True
Any sound above 20000 hertz is what?
ULTRASOUND.
Humans can only hear sound from 20 to 20000 hertz.
T or F?
True
