Waves

• a wave is a vibration that transfers energy from one place to another
• waves do not transfer matter, only energy
• mechanical waves require a medium to travel through
• electromagnetic waves do not require a medium
• a transverse wave makes things oscillate vertically
• transverse wave:

  
• longitudinal wave:

  
• the direction of a wave is parallel to the movement of the source
• a wavelength of any wave is the distance between two matching points on neighbouring waves
• the amplitude of any wave is a maximum distance a point moves from its rest position
• the frequency is the number of waves passing any point each second
• sound requires a medium to travel, for example air or water
• electromagnetic waves are transverse waves made up of electric fields
• all objects with thermal energy emit infared radiation