Biconcave Lens: Observation Experiment

Aim

To learn how lenses bend light.

Prior Knowledge

• The law of refraction.
• The concept of a normal line.
• Geometry of a sphere.

Description of the Experiment

The lens used in the experiment has two surfaces which are segments of a sphere. It is made of glass. Observe the experiment. Explain your observation using your knowedge of refraction.

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Questions

• Why did the rays bend after entering the lens? Why did they bend after leaving the lens?
• Use a ray diagram to explain your observation.
• Decide what practical applications of lenses one might invent after observing and explaining this experiment.