LIGHT AND LENSES by Ms. Mendoza 5th Grade Lincoln Elementary

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LIGHT AND LENSESbyMs. Mendoza5th Grade
Lincoln Elementary
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WHAT HAPPENS TO LIGHT?

• When light strikes an object, two things can
  happen
• Reflection Refraction

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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
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REFRACTION

• Refraction occurs because light bends.

Click for more information on refraction
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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
• Concave
• Convex

Click the picture above for more information
about lenses.
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Concave and Convex Lenses

• Look at the convex and concave lenses below

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The curved surface/surfaces of a lens bends the
light.  Notice the paths of light of the convex
and concave lenses shown below.

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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.

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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.

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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