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M o d e l N o . O S - 8 5 1 5 B
E x p e r i m e n t 7 : H o l l o w L e n s
19
Experiment 7: Hollow Lens
Purpose
In this experiment you will explore how the properties of a lens are related to its
shape, its index of refraction, and the index of refraction of the surrounding medium.
Background
A
conventional lens is made of a material whose index of refraction
is higher than that of the surrounding medium. For instance, the
lenses in a pair of eyeglasses are usually made from glass or plastic
with an index of refraction of 1.5 or higher, while the air surrounding
the lenses has an index of refraction of 1.0. However, a lens can also
have a
lower
index of refraction than the surrounding medium, as is
the case when a hollow lens is “filled with air” and surrounded by
water. (The index of refraction of water is about 1.3.)
The hollow lens in this experiment has three sections: a plano-con-
cave section and two plano-convex sections. We will refer to these as
sections 1, 2, and 3 (see Figure 7.1).
You will determine whether each section acts as a converging or
diverging lens when it is
a)
filled with water and surrounded by air
and
b)
filled with air and surrounded by water.
Procedure
1.
Before you test the hollow lens, make some predictions: For every configuration
in Table 7.1, predict whether incoming parallel rays will converge or diverge
after passing through the lens. Record your predictions in the table.
2.
Place the light source in ray-box mode on a white sheet of paper. Turn the wheel
to select five parallel rays.
3.
Fill section 1 with water and place the lens in front of the light source so the par-
allel rays enter it through the flat side. Do the rays converge or diverge after pass-
ing through the lens? Record your observation in Table 7.1.
Required Equipment from Basic Optics System
Light Source
Hollow Lens from Ray Optics Kit
Box from Ray Optics Kit (with lenses and foam insert removed)
White Plastic Sheet from Ray Optics Kit
Other Equipment
Water
Paper towels
White paper
Small weight (to stop lens from floating)
Eye-dropper (optional, for removing water from the hollow lens)
1
2
3
Figure 7.1: The hollow lens
Summary of Contents for OS-8515B
Page 6: ... Basic Optics System About the Experiments 6 ...
Page 26: ... Basic Optics System Experiment 9 Apparent Depth 26 ...
Page 38: ... Basic Optics System Experiment 13 Telescope 38 ...
Page 42: ... Basic Optics System Experiment 14 Microscope 42 ...
Page 44: ... Basic Optics System Experiment 15 Shadows 44 ...
Page 46: ... Basic Optics System Telescope and Microscope Test Pattern 46 ...