Reflection, Absorption, and
Refraction of Light
Vocabulary:
reflection, absorption, transmit,
refraction
When Light Strikes an Object
• Light travels in a straight line.
• It will continue moving in a straight line, until
it hit something.
• Depending on what it hits, light may behave in
very different ways.
Reflection
• Laws of Reflection
– https://www.youtube.com/watch?v=vtSG7Pn8UU
Reflection
• The law of reflection
states that the angle
of reflection is equal
to the angle of
incidence.
– A ray that hits the
surface is the incident
ray. The ray that
bounces off the
surface is the reflected
ray.
*An incidence is the
intersection of a line, or
something moving in a
straight line, such as a
beam of light, with a
surface.
Reflection
Reflection
• When light bounces off a surface/objects at
equal angles, it is called reflection.
• When light is reflected it travels in a straight
line away from the reflecting surface.
• Interactive Example of Reflection:
http://www.openschool.bc.ca/elementary/scien
ce4/html/bouncingLight.htm
Absorption
• Taking in light.
• Energy transferred
from light to heat.
• Color is produced by
the absorption of
selected wavelengths
of light by an object.
Absorption
• Any time light hits a
surface, some of it is
absorbed, or taken in.
• When light is absorbed into
a surface it is transformed
from light energy, into heat
energy.
• That is why on a sunny day
it is cooler to wear a white tshirt, than a black t-shirt;
dark surfaces absorb more
light than lighter surfaces.
Refraction
• Light BENDING when
it goes from one
transparent medium
to another.
sunlight
air
glass
• Examples:
– Air to water
– Air to glass
Refraction
• Some materials transmit
light, or allow light to
pass through them.
– Rays that pass through a
surface are called
transmitted rays.
• These transparent
materials cause light to
bend as it is passing
through the surface.
• When the light bends, it
makes things look like
they do not match up.
Refraction continued…
• How light bends
depends on how the
atoms of the two
materials absorb energy
and the angle of the
light.
• This causes the light to
change speed. The
direction of the bend has
to do with whether light
speeds up or slows
down.
Basics of a telescope
(refraction)
• 2 lenses are used to bend light.
http://www.myschoolhouse.com/
courses/O/1/36.asp
• Click above to see a
diagram of the
difference between
the two types of
lenses (Concave and
Convex)
• These types of lenses
are used everyday to
BEND light.
• Concave lenses
converge light.
• Convex lenses
diverge light.
Questions
1. Which color absorbs the most light?
2. When light bounces off a surface, what is it
called?
3. Describe what happens to light when it
passes through glass or water.
4. What happens to a material when it absorbs
light?
5. On a summer day, why is blacktop so much
hotter than the dirt next to it?