Infrasound and ultrasound

Question 1

What animals use infrasound to communicate between heards over long distances?

Answer 1

elephants and giraffes

Question 2

How do scientists track herds in dense forests?

Answer 2

use microphones

Question 3

What can infrasound be used to track?

Answer 3

it can detect volcanoes, as a volcano erupts it produces infrasound.
to track passage of meteors through the atmosphere.

Question 4

What is ultrasound?

Answer 4

waves that have frequencies above 20000 hertz. This is the above normal hearing range for humans, so we cannot hear it.

Question 5

What happens when ultrasound waves reach a boundary between to substances with different densities?

Answer 5

they are reflected back and the remainder of the ultrasound waves continue to pass through.

Question 6

what are some uses of ultrasound?

Answer 6

checking manufactured objects such as railway tracks, oil pipelines to check for any damage or defects. 
scanning babies (ultrasound scan)

Question 7

what is sonar?

Answer 7

a system for the detection or objects under water by emitting sound pulses and detecting or measuring their return after being reflected

Question 8

how is sonar used?

Answer 8

on ships and submarines to detect fish or the seabed. A pulse of ultrasound is sent out from the ship and it bounces off the seabed or shoal of fish and the echo is detected. The time is taken for the wave to travel indicates the depth of the sea bed or shoal of fish.

Question 9

What is infrasound?

Answer 9

less than 20 hertz. This is below the range that human can hear