Waves 1
a disturbance or vibration that transfers energy through matter or space
Wave
What is a medium?
The material that the wave travels through, Most waves need to travel through a substance.
Particles in a medium return to their original position after the disturbance/vibration passes through, what am I?
Equilibrium/Rest position
Matter in the medium moves back and forth at right angles (perpendicular) to the direction that the wave travels
Transverse wave
Matter in the medium moves back and forth in the same direction that the wave travels
Compressional waves
What are seismic waves?
combination of transverse and compressional – travel through earth and on earth’s surface – like earthquakes (very destructive)
Distance between one point on a wave and the nearest identical point. Crest-crest; trough to trough
Wavelength
When frequency increases, what happens to the wavelength?
the wavelength gets shorter (more waves per second = fit more waves into the same distance = shorter waves)
What does the speed of a wave depend on?
the medium the wave travels through -
Sound travels faster in liquids & solids than in gases
Light waves travel fastest in gasses or empty space
What are frequency and wavelength measured in?
Hertz and Meters (cm, mm, m)
What is the formula and units for calculating speed of a wave?
Speed = freq x wavelength
Units - meters/cm
Define frequency
the number of wavelengths that pass by a fixed point in one second
Define amplitude of a transverse and what it measures
Height of a transverse wave is rest to crest, or rest to trough .
It measures strength/intensity of a wave
How do you measure the amplitude of a compressional wave?
Density of compressions (squish!) and rarefactions.
coils are closer together in compressions (amp is high) and farther apart in decompressions (amp is low)
What are EM waves?
Electromagnetic waves - Radiant energy that can travel through space - no medium required.
True or False: EM waves travel slowest in solids and faster in gases
True
Which color has the longest wavelength of visible light and which has the shortest?
Red light longest wavelength - shortest frequency
violet shortest wavelength - highest freq
True or false: Radio waves have a higher frequency than microwaves.
False! Radio waves have the lowest frequencies and longest wavelengths in the electromagnetic spectrum.
True or false: Radio waves have the most energy, and gamma rays have the least energy
False
How do X-rays work? Are they safe?
The machine sends the xrays through your body and they xrays cannot go through your bone so an image of your bones shows up on the picture.
It is not safe to have repeated xrays done since they are higher energy waves.
How long is a wave with a speed of 24 m/s and a freq of 12 Hz?
w = s/f
24m/s / 12Hz = 2m
Why does the James Webb telescope see better than the Hubble? What type of wavelength used in the Webb?
Bigger mirror = more light coming in = clearer pictures! Mostly infrared, some visible.
Why are Gamma rays very bad for you to be around, but radio waves are harmless? Give an example of each type of wave.
Gamma are very high energy, radio waves are low energy, not enough to damage DNA directly.
Gamma - cancer therapy
Radio - satellite and cable TV
What two types of EM energy used in cancer therapy and what are the side effects?
Xray and Gamma both used. The patient is zapped with the energy wherever the cancerous cells are, and it kills the cancer cells. It can cause burns on the skin surface
Which properties of a wave can increase when more energy is added?
Frequency and amplitude