Cycle
distance between two consecutive points on a wave that (from crest to crest or trough to trough)
Oscillation
the displacement/vibration of a wave
Amplitude
distance from midline to crest
Period
one wavelength in a displacement/time graph
Wavelength
distance between two consecutive points on a wave that are in phase, such as the distance between two adjacent peaks (lambda λ) in meters (m)
Frequency
the number of complete wavelengths that pass a point in a given time
Crest
maximum point in a transverse wave
Trough
minimum point in a transverse wave
Velocity Formula for a wave
v = fλ
Transverse Wave
wave energy runs perpendicular to wave distance
Longitudinal Wave
displacement parallel to distance
Electromagnetic Spectrum
transverse waves (radio, visible, and gamma) where energy can be transmitted though empty space (vacuum)
Reflection
waves bounce from smooth, flat surfaces to reflect an image (when light rays bounce back) or produce an echo (sound waves bounce back)
Refraction
needs 2 mediums where a ray will go through the different mediums and change speed and direction because of the different densities
Diffraction
waves going through a barrier with a gap (big or small) and change direction
Intensity
amount of energy in a wave (decibels)
Timbre
how well music/sound comes across in harmony (sound quality)
Pitch
how high or low a sound is (depends on frequency + is how fast molecules vibrate)
over 20,000 Hz = ultrasonic sound
Longitudinal vs. transverse waves
Longitudinal: displacement/direction
Transverse: displacement/time
Mechanical vs. EM Waves
mechanical: not capable of transmitting energy through empty space
EM: can transmit energy through empty space
Sound vs. light
Sound:
mechanical waves
require a medium to travel through (air or water)
longitudinal waves = particles in the medium vibrate parallel to the direction of wave propagation
lower frequencies and bigger wavelengths
Light:
electromagnetic waves
can travel through a vacuum (empty space)
transverse waves = particles in the medium vibrate perpendicular to the direction of wave propagation
higher frequencies and smaller wavelengths
Colors of light
ROYGBIV
red
orange
yellow
green
blue
indigo
violet
Usage of the different wavebands of EM Spectrum
radio waves: radios and TVs (longest wavelength)
microwaves: used for heating
infrared radiation: used for heating
visible light: narrowband of wavelengths that humans can see (ROYGBIV)
ultraviolet radiation: absorbed by/harmful for skin
X-rays: used to see through objects/bodies
gamma rays: harmful + used to treat cancer (smallest wavelength)
Doppler Effect, when is the frequency higher? Lower? Why?
Change in frequency & pitch of a sound due to observer/sound source’s motion
frequency = higher when sound source moving towards receptor vs. lower when sound source moving away from receptor
3 properties of sound
Intensity, Pitch, Timbre