Objective – Investigate and describe the refraction of light passing through various materials (e.g., prisms, water).
Laser Jell-O
(Exploratorium Snacks)
Use gelatin as a smoked lens, to view total internal reflection, and as a color filter.
Materials
 D-shaped refraction cup with red Jell-O™
 D-shaped refraction cup with blueberry Jell-O™
 Laser pointer
1. Shine the laser through the red gelatin. Record your observations.
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2. Shine the laser through the blueberry gelatin. Record your observations.
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3 Using the red gelatin and the curved side of the dish, shine the laser in the center of the dish.
Move the laser from the center to the outside edge. Notice the change and measure the angle of
refraction. Record your observations.
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Objective – Investigate and describe the refraction of light passing through various materials (e.g., prisms, water).
4 Turn the dish around. Shine the laser in the middle of
the straight edge. Move the laser to the outside edge so
that the beam reflects off the surface of the gelatin and is
re-emitted parallel to the incoming beam. Repeat the
activity, bouncing the beam off the straight side, to
measure the critical angle. Record your observations.
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5. If you have two lasers, align them parallel and shine
them through the curved side of the dish. Use a white
piece of paper or waxed paper as a screen to find the focal
point. Invert the gelatin lens onto a piece of waxed paper-it may need a little prying to get it to come out. Use the
empty dish as a cookie cutter to make a concave lens out
of the original convex gelatin lens. Shine parallel lasers
through the new lens.
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