Types of Waves

Types of Waves

1. Sound Waves

   • Vibrating objects creates sound waves. They are longitudinal mechanical waves and cannot pass through a vacuum.
   • All sound waves can be reflected (echos), refracted or diffracted. Loud sound waves have a large amplitude and quiet sounds have small amplitudes.
   • Frequency measures the number of cycles per second.
   • High pitched notes have a short wavelength and a high frequency. The higher the frequency of a wave the more it can carry.
   • Oscilloscope
     • Amplitude is the height from the midpoint to the highest or the lowest points.
     • The wavelength is the distance from one peak to the next.

2. Light & Mirrors

   • Ray diagrams show how rays are reflected / refracted.
   • The diagram shows a ray being reflected.

3. Electromagnetic Waves

   • The Electromagnetic Spectrum
     • Electromagnetic radiation is a continuous spectrum of transverse waves carrying energy.
     • They travel at the speed of light and they travel at the same speed in a vacuum.
     • They can behave like particles and waves.
   • Dangers
     • Microwaves are strongly absorbed by water, passing through skin and heating up cells - they do no cause cancer by research is being done as phones cause harm but not serious risk.
     • Infrared can cause burns, visible light can damage cells in the retina, ultraviolet can cause sunburn or skin cancer and x-ray and gamma rays can kill or damage cells.
     • Gamma, x-ray and ultrviolet are ionising and can ionise the DNA in the nucleus - the cell may die or cause mutations.

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