Waves

What is a wave?

• Disturbance of particles in medium
• Come in two distinct types: longitudinal and transverse
• Have a repeating pattern
• Have many parts
• Don't move the matter with the energy
• Some waves need a medium, some don't

Examples of Waves

• Sound
• Light
• Water
• Vibrations
• Microwaves
• X-Rays
• Radio
• AND MORE!

Wave Rules

• All need a source
• Mechanical waves need a medium
• Longitudinal waves must be mechanical
• Lose energy as they travel through a medium
• Travel faster in a less dense, more elastic medium
• Wavespeed is constant in a given medium

Transverse Waves

• Moves energy perpendicular to the disturbance of particles
• All electromagnetic waves (light, radio, microwaves, x-ray, gamma rays)
• Have crests (high points of waves) troughs (low points of waves)

Longitudinal Waves

• Moves energy parallel to the disturbance of particles
• Made of compressions (areas of high density) & rarefactions (areas of low density) in the particles of a medium
• Requires a medium (particles to push)

Parts of Waves

• Wavelength: distance between 2 sucsessive crests or troughs
• Frequency: speed, number of vibrations per sec, measured in Hertz (Hz), frequency is wavespeed divided by wavelength (f = c / λ)
• Amplitude: measurement of displacement of the wave from the resting position

Wave Interactions

• Interference: combining waves, can be constructive (get bigger) or destructive (cancel each other out)
• Diffraction: waves bending as they pass through and opening/around a corner

Wave Interactions (Cont.)

• Refraction: change in speed/direction that happens when it passes between mediums (the wave bends)
• Reflection: a wave bouncing off of an barrier and creating another wave