waves ^_^

• amplitude is the maximum displacement from its undisturbed position
• wavelength is he distance between the same point on adjacent waves
• frequency is the amount of waves which pass a particular point in one second
• period is the amount of times a full cycle of waves to pass a point
• specular reflection happens when a wave is reflected in a single direction by a smooth surface (e.g a mirror)
• diffuse reflection is when a wave is reflected by a rough surface and the reflected waves are scattered
• the higher the density the slower the wave travels
• electromagnetic scale is radio waves, microwaves, infra red, visible light, ultra violet, x-rays and gamma rays
• all electromagnetic waves are transverse and travel at the same speed through a vacuum or air
• Electromagnetic waves are made up if oscillating electric and magnetic fields
• you can produce a radio wave by using an alternating current in a circuit.
• radio waves are used in communication
• Long radio waves bend around the world and can diffract around other things such as mountains and tunnels meaning they can travel very far.
• short wave radio signals reflect off the ionosphere
• radio waves used for TV and radio have short wavelengths and the transmitter must be in direct sight of the absorber
• water absorbing microwaves are used to penetrate food and transfer the energy to the water molecules in the food causing it to heat up.
• infra red radiation is given out by all objects and the hotter the object, the more infra red.
• infrared cameras can be used to detect radiation and temperature
• fibre optic cables are thin glass or plastic wires which carry data. the reflection of the ray bounces back and fourth until they reach the end of the cable
• x rays easily pass through flesh but not through denser materials like bone or metal.
• high dosages of x rays and gamma rays kill all living cells so can help treat cancer
• low frequency waves pass through soft tissue without being absorbed
• high frequency waves all transfer lots of energy and so can cause damage to humans
• UV radiation damages surface cells which can lead to sunburns and can cause skin cancer and serious side effects such s blindness and an increased risk of cancer
• x rays and gamma rays are types of ionsisng radiation which can cause gene mutations or cell destruction and cancer