Physics: Waves and Behaviors Notes

Waves

• Waves - repeated motion/vibrations that travel through a medium
• Waves are good for a transportation of energy between different points
• Parts of a wave that is measurable: wavelength, amplitude, wave speed, period, and frequency

Types/Categories of Waves

• Mechanical waves - requires a medium (sound, water)
• Electromagnetic waves - created by stars and celestial objects, no medium is needed (radio)
• Radio waves - emitted by radio stations and stars
• Microwaves - easily absorbed by water (radar, cell phone)
• Infrared - "below red," associated with heat (night vision, weather forecasting)
• Visible Light - only part of spectrum you see
• Ultraviolet waves - "beyond violet" (kills viruses, lowers sunburns)
• X-rays - imaging bones, radiotherapy
• Gamma rays - generated from nuclear reactions (stars, bombs)
• Light waves - don't require a medium, travels fastest in a vacuum 
• Speed of light - 3.00x10^8 m/s
• Medium - material the wave travels through
• Some require a medium to travel while others do not
• Transverse and longitudial/compression waves

Other Vocabulary

• Pulse - one wave that travels through a medium
• Continuous - repeatedly move up and down
  

Parts of a transverse Wave

• Transverse waves - moves perpendicular
• Crest - top of the wave
• Trough - bottom of the wave
• Amplitude - distance from center to crest trough

Parts of a compression wave

• Compress zone - particles close together
• Rarefaction zone - less dense area
• Compression waves - moves parallel
  

Calculating Wave Speed

• Period (T) - time it takes for one length to pass (units = s)
• Frequency (F) - number of waves that pass each second
• Hertz (Hz) - 1 Hz = 1 wave per second
• Wavelength - one complete cycle of a wave
• Equation for Wave Speed - Speed = frequency x wavelength

Wave Interference

• Occurs when two waves run into each other
• Temporary create one wave with different amplitudes
• Amplitude- measure waves height and energy

Constructive Interference

• Two waves combine to form a larger wave
• Waves are in phase - amplitudes add together

Destructive Inteference

• Two waves combine to form a smaller wave
• If the crest of one wave coincides with trough of second wave = out of phase (cancels out)

Rogue Waves

• Created by superposition of waves
• Superposition - combining of waves 

Standing Waves

• Caused by two waves inferring with one another continuously
• Looks like it is still