What does the universe look like in color?

this is a source of light. Examples may include fire, incandescent
lights, fluorescent lights, the Sun, the stars, TV screens, those funny
light sticks they hand out at carnivals, luminescent dials on watches
and clocks, neon signs, blinking LED displays, fireflies and other
glowing creatures, auroras, etc. A traffic light might not be accepted
as a separate example, because the source is an ordinary light bulb
inside the device.
Point out to students that although we see light indoors and out, there
are relatively few different sources of light. These few sources light
our entire world, indoors and out.
Which of the sources you named are hot?
Go back through the class' list and have students identify which
items are sources of light by virtue of being hot enough to glow.
Examples include the Sun, fire, a glowing oven or hot coals,
incandescent bulbs, and the stars (though we have no direct
experience with the stars).
Many of the light sources on the list are not hot. Examples are the
red and green lights (LEDs) in electronic equipment, the glow of TV
screens, fluorescent bulbs, neon signs, auroras etc. These sources
must produce light by some means other than being hot enough to
glow.
Is the Moon a source of light? Is the daytime sky a source of
light?
The Moon is bright enough to cast shadows at night, but is it the
source of light? Ask students whether the Moon gives off its own
light, or merely reflects the light from some other source. This is a
good opportunity to remind students that the Sun is the source of the
Moon's light; the moonlight we see is reflected light whose source is
the Sun.