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
• <font size="3">Microwaves - easily absorbed by water (radar, cell phone)</font>
• <font size="3">Infrared - "below red," associated with heat (night vision, weather forecasting)</font>
• <font size="3">Visible Light - only part of spectrum you see</font>
• <font size="3">Ultraviolet waves - "beyond violet" (kills viruses, lowers sunburns)</font>
• <font size="3">X-rays - imaging bones, radiotherapy</font>
• <font size="3">Gamma rays - generated from nuclear reactions (stars, bombs)</font>
• <font size="3">Light waves - don't require a medium, travels fastest in a vacuum </font>
• <font size="3">Speed of light - 3.00x10^8 m/s</font>
• Medium - material the wave travels through
• Some require a medium to travel while others do not
• Transverse<font size="3"> and </font><font size="3">longitudial/compression</font><font size="3"> waves</font>

Other Vocabulary

• <font size="3"><font size="3">Pulse - one wave that travels through a medium</font></font>
• <font size="3"><font size="3">Continuous - repeatedly move up and down</font></font><font size="3">
  </font>

<font size="3">Parts of a transverse Wave</font>

• 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
• <font size="3">Equation for Wave Speed - Speed = frequency x wavelength</font>

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