14.2 – Light
Infrared wave: electromagnetic wave with a
wavelength shorter than a microwave but
longer than light.
Ex: Remote controls (TV, DVD player, etc.)
use infrared waves. We feel heat from
infrared waves (Ex: the sun, a heater, fire.)
Intensity: amount of energy that passes
through a square meter of space in one
second.
Opaque: material that light does not pass
through.
Ex. Wood, metal,
cardboard
Radio wave: low frequency, low energy
electromagnetic wave that has a wavelength
longer than about 30cm.
Ex: Radios, TVs, Cell phones, satellites, WiFi.
Range: set of values from least to greatest.
Translucent: material that allows most of
the light that strikes it to pass through, but
through which objects appear blurry.
Ex: Sheer fabric, thin
paper, sunglasses.
Transparent: material that allows almost all
of the light striking it to pass through, and
through which objects can be seen clearly.
Ex: Clear glass, windows,
water, clear plastic.
Ultraviolet wave: electromagnetic wave
with a slightly shorter wavelength and
higher frequency than light.
Ex: These waves from the sun cause
sunburn; fluorescent light; used to harden
substances in dentistry and nail salons.