6.1 Waves

• waves transfer energy from one place to another without transferring any matter
• waves transfer energy in the direction they are travelling
• when waves travel through a median the particles of the median oscillate and transfer energy between each other.

  however mostly particles stay in the same place - only energy is transferred
• the amplitude of a wave is the maximum displacement from its undisturbed position
• the wavelength is the distance between two adjacent points on a wave
• frequency is the number of waves passing a point per second, measured in hertz (Hz)
• all waves are either transverse or longitudinal waves
• Time = 1 / frequency
• transverse waves have sideways vibrations and are perpendicular to the direction of energy transfer
• longitudinal waves, their oscillations are parallel to the direction of energy transfer
• Wave speed = frequency X wavelength
• all waves can be absorbed, transmitted or reflected
• waves can be absorbed by the material that the wave is trying to cross into
• waves can be transmitted - meaning they carry on travelling through the material
• waves can be reflected
• angle of incidence = angle of reflection
• the angle of incidence is the angle between the incoming wave and normal
• the angle of reflection is the angle between the reflected wave and the normal
• the normal line is an imaginary line that's perpendicular to the surface at the point of incidence
• reflection can be speculator or diffuse

  waves are reflected at different boundaries in different ways
• specular reflection happens when a wave is reflected in a single direction by a smooth surface
• diffuse reflection is when a wave is reflected by a rough surface, the rays are scattered in lots of different directions