Fresnel Lens

1. Compare the Fresnel lens to the “regular” lens
   on the table. How is a Fresnel lens similar to a
   “regular” lens?

How is it different?

2. Feel the surface of the Fresnel lens. What do
   you notice? Make a sketch of how you think
   the surface might look up close.
3. Hold the Fresnel lens horizontally above a
   sheet of white paper on the table. Can you
   make an image of the overhead lights on the
   paper? Since the source is far away from the
   lens (“at infinity”) the image you see is very
   near the focal point of the lens. The distance
   from the lens to the focal point is the focal
   length of the lens.
4. Measure the focal length (in centimeters) of the
   Fresnel lens with a ruler.
5. How does it compare to the other lenses’ focal
   length?