Science: Waves Flashcards
Any wave transfers XXXX from one place to another
ENERGY
Sound waves cause particles to vibrate backwards and forwards in the direction of the wave, this produces areas of high pressure (called XXXXXX) and low pressure (called XXXXXX)
areas of high pressure (compression) and low pressure (rarefaction)
As there are areas where the air pressure is different in a sound wave, we can call sound waves a type of XXXXX wave
PRESSURE
What can sound be detected and produced with?
Sound can be detected with a microphone, the microphone will change air pressure into a changing potential difference
Sound can be produced with a loudspeaker, the changing potential difference causes changes in air pressure
What are transverse waves?
Transverse waves vibrate at 90o to the direction at which they are travelling, they move up and down as well as forward
What are Longitudinal waves?
Longitudinal waves vibrate in the direction in which they are travelling
What happens when waves are out together?
When waves are put together they superpose, this means
they will either add together or cancel each other out
What happens when waves are in line with each other?
When the waves are in line with one another they add together, increasing the amplitude of the wave
What happens when waves are NOT in line?
When the waves are not in line, they will cancel each other out, decreasing the amplitude of the wave
What sound frequencies can humans hear?
Humans can hear sounds with a frequency between 20–20000Hz.
What is ultrasound?
ultrasound is any sound with a frequency of higher than
20 000 Hz
What can ultrasound be used for?
• Ultrasonic cleaning – dirt particles are ‘shaken’ off of objects
• Physiotherapy – the ultrasound waves causes liquid particles in the body to move more quickly and hence get warmer
Examples of items on the electromagnetic spectrum - from low energy/frequency to high energy/frequency? (And decreasing in wavelength)
+ examples of uses for each type
Radio waves (TV signals)
Micro waves (mobile phone signals)
Infrared (heating and cooking)
Visible light (photography)
Ultraviolet light (detecting forgeries)
X rays (imaging broken bones)
Gamma rays (killing cancer cells)
What is IONISATION?
High energy waves can lead to ionisation, where electrons are knocked off of atoms in cells
This can cause mutations in cells if the DNA is affected and this can lead to cancerous tumours forming