Light Energy
Vocabulary Words
Transverse wave: waves in which the particles vibrate perpendicular to the direction
of the wave, or the energies run perpendicular to each other
Electromagnetic spectrum (abbreviated “EM”): energy made up of a combination of
magnetism and electricity; it is a transverse wave because the two energies run
perpendicular (at right angles) to one another.
To help you out, the diagram below can be used to help you draw the next five words:
Rest position: where the particles stay if there is not wave (no energy making them
move)
Crest: the highest point of a transverse wave
Trough: the lowest point of a transverse wave
Amplitude: the distance between the rest position in a wave, and the crest
Wavelength: the distance between two corresponding points on adjacent (side by
side) waves
Frequency: how many waves go through a point in one second; measured in Hertz
Wave speed: how fast a wave goes; equals wavelength times frequency
Radio waves: the lowest frequency EM wave
Microwaves: next lowest frequency wave after radio waves; used to cook food and is
produced and picked up by your cell phone
Infrared waves: 3rd lowest frequency wave; used to kill bacteria and for night vision
goggles
Visible light waves: the wave in the middle of the EM spectrum; this is the light we
can see
Ultraviolet waves: (abbreviated UV waves); higher frequency than visible light waves,
these are used in tanning beds, and exposure over time can cause skin cancer
X-rays: even higher frequency than UV waves, these can help doctors diagnose
broken bones, but too much exposure has been proven to cause cancer
Gamma rays: highest frequency EM wave, these can kill cancer cells, but also kill
healthy cells; atomic bombs produce them
Opaque: materials that don’t allow light to pass through so we can’t see through them;
most things we see are opaque, like doors, walls, and you!
Translucent: materials that allow SOME light to pass through, but not all of it, so we
can sort of see through it, but the view is changed; wax paper is translucent
Transparent: materials that allow most, or all, the light to pass through, so we can see
through it; window panes and water are transparent
Transmission: when light energy passes through matter, light passes through
transparent material
Absorption: when light energy is taken in by matter, and stops there
Reflection: when energy bounces back after hitting matter
Refraction: when light energy bends because it starts going through a new medium
Concave lens: a lens that is thinner in the middle than at the edges.
Convex lens: a lens that is thicker in the middle than at the edges.