Waves, Light, and Sound
Vocabulary
WAVES
• Mechanical Waves: energy that travels through matter;
examples include sound, ocean waves, and earthquake
waves
• Electromagnetic Waves: form of energy that can travel
through empty space as well as through matter;
includes visible light, radio waves, x-rays, and many
other wavelengths
• Hertz: Measurement of wave frequency equal to
vibrations per second.
• Wavelength: distance from any point on one wave to a
corresponding point on the next wave, such as crest to
crest or compression to compression.
Waves
• Frequency: number of wave vibrations
(oscillations) produced in one second, measured
in hertz (Hz)
• Amplitude: total distance a wave moves
(oscillates) from its resting position.
• Reflection: bouncing back of a wave from a
surface; in light, reflection from a surface is
specular reflection from a rough surface is diffuse
reflection.
• Refraction: bending of a wave as it moves across
the boundary between one medium and another.
Sound
• Longitudinal Wave: a wave that oscillates back and forth
parallel to the direction it is traveling; where the wave
pushes matter closer together is a compression; where the
wave pushes matter farther apart is a rarefaction
• Compression: regions where the coils are closer in a
longitudinal wave
• Rarefaction: regions where the coils are farther apart in a
longitudinal wave
• Pitch: how high or low a sound is; determined by the sound
wave’s frequency
• Decibels: Unit of measurement for the loudness of sound.
Light
• Transverse Wave: a wave that oscillates
perpendicular to the direction it is traveling
• Crest: highest point of a transverse wave
• Trough: lowest point of a transverse wave
• Electromagnetic Spectrum: full range of
electromagnetic waves
Light
• Law of Reflection: states that a wave bounces off a
surface at the same angle that it hits the surface
• Transmission: passage of light through matter; also,
sending of information or energy from one point to
another
• Transparent: describes matter that allows light to pass
through it easily
• Translucent: describes matter that allows some, but
not all, of the light that hits it to pass through, and that
scatters some light
• Opaque: describes matter that light does not pass
through