Book 13, Question 63
Why Do Some Lenses Make Things Look Smaller?
A lens that is thinner in the middle than at the edges spreads light out. That makes things look smaller. It also lets you see a much wider scene.
More fun facts
- Lenses that are thinner in the middle are called diverging lenses, and eye doctors use them to correct nearsightedness.
- In a nearsighted eye, light focuses in front of the retina instead of on it, so far away objects look blurry.
- The diverging lens makes an image closer to the eye than the object, so a nearsighted person can see it clearly.
- Glasses prescriptions for nearsighted people have a negative power, measured in units called diopters.
- Trouble seeing faraway things, squinting and eye strain can be signs of nearsightedness.
- Children who spend more time outdoors are less likely to be nearsighted, but experts are not sure why.
Sources: openstax.org, National Institutes of Health
Questions kids ask
Why do some glasses make eyes look smaller?
Glasses for nearsighted people use diverging lenses, which make things behind them, including eyes, look smaller.
How can I tell if I need glasses?
If faraway things look blurry or you squint a lot, tell a grown up so you can get an eye exam.