waves for detection and exploration Flashcards
Why are sound waves mechanical?
they need a substance to travel through
Why is there a limit to the range of human hearing?
conversion of sound waves in air to vibrations in ear (solid) only works over a limited range of frequencies
What is the frequency range of normal human hearing?
20 Hz to 20 000 Hz
What are ultrasound waves?
sound waves with a frequency above 20000 Hz
What happens to ultrasound waves when they meet a boundary between two substances?
they are partially reflected and some are transmitted
What is echo sounding used for?
detecting objects in deep water, measuring the depth of water
What are the properties of P- waves
longitudinal, travel through liquids and solids
What are the properties of S - waves
transverse, cannot travel through liquids
which observation suggests that the outer core of the Earth must be liquid
S Waves are not detected on the other side of the earth
