Please enable JavaScript.
Coggle requires JavaScript to display documents.
PHYSICS: Waves - Coggle Diagram
PHYSICS: Waves
-
Types of wave
-
Mechanical waves require a medium to travel through. Water waves need water to travel through. Sound waves need something to travel through (That's why no one can hear you in space).
Electro magnetic waves do not need a medium to travel through. Things like light and radio waves can travel through space.
-
Properties of waves
There are compressions and rarefactions, amplitude and frequency, wavelength and crests and troughs.
Compressions and rarefactions are in longitudinal waves. The bit where it is stretched, it is called a rarefaction. The compressed bit is called a compression
-
A crest is the top of the hill and the trough is like the valley. These are found in transverse waves.
-
The frequency is the number that go past a point in a second. The units of frequency is the Hertz (Hz)
-
Wave superposition
When waves are put together, they superpose
This means that if the crests and troughs line up, then the amplitude grows. If they are in opposite directions, then the waves cancel out
Noise cancelling headphones work by listening to the noise they need to cancel, playing a reversed version of the same noise to cancel it out
Sound Waves
Sound is wave created by vibrating objects. Sound waves are longitudinal waves. Sound cannot travel through a vacuum as it needs a medium to pass through. Particles are required to transmit the vibrations.
Sound travels at different speeds in solids, liquids and gases. This is due to the way the particles are arranged. In solids, the particles are closer together so the vibrations are easily passed through the solid. In gases, the particles are further apart meaning that they don't pass the vibrations as easily.
If an object travels fast enough, it can travel faster than the sound it is emitting, creating a sonic boom
How we hear sounds?
-
Sound enters the ear from the pinna. The pinna can detect where the sound is coming from. The sound is then carried to the eardrum via the ear canal. The ear drum vibrates, causing three small bones called the ossicles to vibrate as well. They transfer sound to the cochlea, which has fine hairs which identify
the sound and transfer the sound's information to the brain via the auditory nerve.
Ultrasound
Ultrasound waves are waves that have a frequency higher than 20, 000 Hz. They are used for a variety of things from sonar, cleaning jewellery, finding faults in metal and treating patients.
Ultrasound can be used to clean jewellery as it vibrates the jewellery and takes off dirt, without damaging it
Ships use ultrasound waves to find or track things underwater. They send out ultrasound and listen for the echo. The ship records the time between the echo and it being received by the ship and then calculates the distance of the object using the speed of sound in water
Frequency and Amplitude
When a sound has a high amplitude, it is loud. When a sound has a high frequency, it is high pitched
-
-
-
