Topic Four - Waves And The Earth

Question 1

What is ultrasound useful for

Answer 1

Some animals, e.g. Dolphins use ultrasound to communicate with each other

Sonar - bats emit ultrasound waves that are reflected by things around them and listen for their echoes in order to locate obstacles and objects in their environment

Question 2

What is infrasound

Answer 2

Sound with frequencies less than 20 Hz

Question 3

What is infrasound used for

Answer 3

Used for the detection of meteors and volcanic eruptions and used by animals to communicate

Question 4

P waves and S waves

Answer 4

P waves - longitudinal waves
~ push and pull on the rock as the wave passes
~ travel faster than S waves

S waves - transverse waves
~ move the rock particles from side to side as the wave travels down
~ travel slower than P waves

Question 5

Seismic waves

Answer 5

Movements inside the earth, such as earthquakes, cause waves to be transmitted through the earth - these are called seismic waves
When seismic waves reach the surface of the earth, the ground shakes
Seismometers are instruments that can detect seismic waves, helping scientists to model the structure of the Earths interior

Question 6

What is ultrasound

Answer 6

Higher than 20,000 Hz