Wait a few
Light can travel in a vacuum. A vacuum is empty space. There are no molecules of air of
anything else in a vacuum. Like all forms of electromagnetic waves, light can travel through
empty space, as weli as through matter.
Light can be absorbed. Absorbed light energy is converted into some other form, such as
mal or heat energy. You can test this by putting a piece of black construction paper and
ece of white construction paper on a sunny windowsill. Place a thermometer for measuring
paper.
9)
or room temperature under each piece of
hours, and then check the two temperatures. The thermometer underneath the black paper
should be hotter than the one under the white paper. This is the reason people tend to wear dark
colors in the (10)
and white or light colors in the summer. Dark
colors absorb light, (11)
us keep warmer in the winter. In the
summer, light colors absorb little of the sun's energy, keeping us (12)
Light can be reflected. If you shine light on a surface, some
of that light will bounce off, or be reflected by, the surface. The law of reflection tells us that
light will always be reflected by a
surface at the same angle at which it hits the surface.
Light can be refracted. Light always travels in straight (13)
But when it passes from one medium into another, it changes direction slightly. Refraction
occurs because light travels at different speeds through different materials. When light passes
through air into water, for example, it slows down. The light rays are bent slightly. You can
e this if you put a pencil into a half-glassful of water. The pencil looks bent or broken at the
aier (14)
This is due to (15)
jbjects that we see get their color from the light they reflect. A green object looks green
because it absorbs all other colors but reflects green.
Light can be transmitted. Sometimes light passes through matter. This is called
transmission. Light is transmitted through some matter more easily than through other kinds of
matter. Light is transmitted through water, air, and glass very easily. These materials are said
to be transparent. Transparent materials (16)
transmitted through them easily. Some matter transmits some, but not all, of the light that hits
it. This
light to be
(17)
material are (18)
is called translucent. Some examples of translucent
paper or glass blocks. Opaque matter does not
transmit any light. You cannot see through it because light doesn't pass through it. A book and
a brick wall are two examples of opaque (19)​