Lenses and the eye

What this chapter teaches

The cornea and the lens of the eye bend light to make a small upside down image on the retina, and the brain makes sense of it. Short sight needs diverging lenses and long sight needs converging lenses. A round jar of water is a converging lens in one direction, so writing looks wider.

Three questions to ask

There is no one right wording. Listen for the idea.

1. Where does the image form in the eye, and which way up is it?
2. Why does a diverging lens help a short sighted eye?
3. Why does writing look wider through a jar of water?

After the chapter, the learner can

• Explain how the lens in the eye makes an image
• Explain how glasses help people see clearly
• Use a jar of water as a lens to make text look bigger