LIGHT AND LENSES
by
Ms. Mendoza
5th Grade Lincoln Elementary
WHAT HAPPENS TO LIGHT?
When light strikes an object, two things
can happen:
Reflection
Refraction
REFLECTION
Reflection occurs when light
bounces off objects. How
much reflection depends upon
how even the surface is. If the
surface is rough, the light
scatters. If the surface is
smooth and flat, the light will
bounce off it at equal
angles. That is why a flat
mirror reflects a good likeness
of the object being reflected.
Click above
REFRACTION
Refraction occurs
because light bends.
Click for more information on
refraction
How does this relate to lenses?
A lens is a device that bends light.
A lens is a piece of transparent
material.
If it is transparent, you can see
through it.
It is usually made of glass and
has at least one
curved surface.
There are two types of lenses:
1.
Concave
2.
Convex
Click the
picture above
for more
information
about lenses.
Concave and Convex Lenses
Look at the convex and concave lenses
below:
The curved surface/surfaces of a lens bends the light.
Notice the paths of light of the convex and concave lenses shown below.
Convex Lenses
A convex lens is thicker in the middle.
A convex lens bends light rays so that they
meet at a focal point. This means that the
Light rays are converging.
Concave Lens
A concave lens is thinner in the middle.
A concave lens bends light rays to make
them spread out. This means that the
light rays are diverging.
Answer the questions about
reflection and refraction
1. _____________ occurs when light bounces off an object.
2. _____________ occurs when light is bent.
3. When light strikes a surface that is rough, the light will ______________ .
4. When light strikes a surface that is smooth, the light will bounce off at equal
______ .
5. What type of material is a lens?
a. transparent
b. translucent
c. opaque
6. The path of light through a concave lens is
a. not directed to a single focal point
b. directed to a single focal point
7.The path of light through a convex lens is
a. not directed to a single focal point
b. directed to a single focal point