5.52. Visible Light and Matter http://www.ck12.org
FIGURE 5.111
Q:What might be another example of light scattering?
A:When light passes through smoky air, it is scattered by tiny particles of soot.
Absorption
Light may transfer its energy to matter rather than being reflected or transmitted by matter. This is calledabsorption.
When light is absorbed, the added energy increases the temperature of matter. If you get into a car that has been
sitting in the sun all day, the seats and other parts of the car’s interior may be almost too hot to touch, especially if
they are black or very dark in color. That’s because dark colors absorb most of the sunlight that strikes them.
Q:In hot sunny climates, people often dress in light-colored clothes. Why is this a good idea?
A:Light-colored clothes absorb less light and reflect more light than dark-colored clothes, so they keep people
cooler.
Classifying Matter in Terms of Light
Matter can be classified on the basis of its interactions with light. Matter may be transparent, translucent, or opaque.
An example of each type of matter is pictured in theFigure5.112.
- Transparentmatter is matter that transmits light without scattering it. Examples of transparent matter include
air, pure water, and clear glass. You can see clearly through transparent objects, such as the top panes of the
window 5.112, because just about all of the light that strikes them passes through to the other side. - Translucentmatter is matter that transmits light but scatters the light as it passes through. Light passes through
translucent objects but you cannot see clearly through them because the light is scattered in all directions. The
frosted glass panes at the bottom of the window 5.112 are translucent. - Opaquematter is matter that does not let any light pass through it. Matter may be opaque because it absorbs
light, reflects light, or does some combination of both.
Examples of opaque objects are objects made of wood, like the shutters in theFigure5.113. The shutters absorb
most of the light that strikes them and reflect just a few wavelengths of visible light. The glass mirror 5.113 is also
opaque. That’s because it reflects all of the light that strikes it.