Waves Flashcards
What is frequency?
The number of waves passing a point each second
What is wavelength?
The distance between a point on one wave and the same point on the next wave
What is amplitude?
The distance between the top and bottom of the wave divided by 2 (the distance between the middle and top of the wave)
What is period?
1/frequency
What is wave speed?
The speed of a wave (measured in m/s)
What are longitudinal waves?
Waves where the particles in the material the wave is travelling through move back and forth along the same direction that the wave is travelling
What are transverse waves?
Waves where the particles in the material that the wave is travelling through move at right angles to the direction that the wave is travelling through
Give a few examples of longitudinal waves
- Sound waves
- Seismic P waves
Give a few examples of transverse waves
- Light waves
- Water waves
- Seismic S waves
What 4 things can happen when a wave reaches a boundary?
It can either be refracted, reflected, absorbed or transmitted
What is a crest?
The top of a wave
What is a trough?
The bottom of a wave
What is transmission?
When a wave is transmitted/passes through a material
What is absorption?
When a wave is absorbed by a material
What is reflection?
When a wave is reflected back the way it came by a material
What is refraction?
When a wave changes speed and direction when it passes through a material
When are sound waves produced?
When objects vibrate
How are sound waves produced from a drum?
The drum is hit and the skin begins to vibrate and particles of air are compressed together. The drum skin then bounces back and the compressed particles move inwards. This causes a sound wave to move outwards from the drum
How does the ear detect sound?
Sound waves are channelled down the ear canal and cause the ear drum to vibrate. These vibrations pass through the ear further and are converted into electrical signals and carried to the brain
Why can the ear only hear sounds in the range 20Hz- 20,000Hz?
The conversion of sound waves to vibrations only works in a limited frequency range
What is infrasound?
Sound waves that have a frequency below 20Hz. Travel through the earth as shockwaves from tsunamis, earthquakes or volcanoes
What is ultrasound?
Sound waves with a frequency above 20,000Hz. Used in pre-natal scans to make images of the inside of the body
What is sonar?
Equipment used to find the depth of water beneath objects using pulses of ultrasound
What does the speed of sound in a material depend on?
The density of the material
What is dispersion?
When light separates out into the different colours making it up due to their different frequencies
