What do people who are blind see?

What do people who are blind see?

Lesson narration:
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DISCUSS (1 of 3):

Why do you think some people have problems with vision?

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DISCUSS (2 of 3):

How could we figure out how eyes work?

Here’s what we came up with...

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DISCUSS (3 of 3): Look at these eyes, and the eyes of the person next to you. What's the same? What's different?

Eyes Comparison

Do you think that any of the differences could explain why some people have trouble with vision, or not?

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Discussion

Why does a lens make an image appear upside-down?

The lenses in your eyes are known as “convex” lenses: they’re curved outward. As light rays enter the far edges of a convex lens, the light rays are bent inwards. In other words, light rays entering the top of the lens bend down toward the bottom of the retina, and light rays coming in from the bottom of the lens bend toward the top of the retina. This is why the image looks upside-down! (You might wonder: Why don’t we see everything upside-down? That is a question which puzzled scientists… learn more!

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Discussion with Video

Why don't we see everything upside-down?

Light makes an upside-down picture on the retina of your model eye. The picture on the retina of your real eye is also upside down. So why don’t you see everything upside-down? Ask your students if they can think of an experiment that might answer this question.

Here's an experiment some scientists tried. They had someone wear eyeglasses that flipped the picture in their eyes so it was right-side-up. To find out what happened, watch this video.

It turns out that the answer is not in your eyes -- but in your brain. Your brain learns to make sense of the picture in your eyes -- whether it's right-side-up or upside-down.

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vision


1 of 12

the ability to see
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light


2 of 12

what comes from the Sun and lamps and makes it possible to see things
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pupil


3 of 12

the dark opening in the center of the eye
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iris


4 of 12

the colored part of the eye that is shaped like a donut
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cornea


5 of 12

the clear layer in front of the eye
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retina


6 of 12

the back of the eye that senses light and sends messages to the brain
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structure


7 of 12

the specific form and shape of something
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function


8 of 12

what something does
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lens


9 of 12

a clear object that changes the direction of light as it passes through
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experiment


10 of 12

a test used to discover new information about a question
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model


11 of 12

a pretend version of something that scientists use when the real thing is too big, small, or complicated to work with
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dissect


12 of 12

to take something apart to study it
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Image & Video Credits

Mystery Science respects the intellectual property rights of the owners of visual assets. We make every effort to use images and videos under appropriate licenses from the owner or by reaching out to the owner to get explicit permission. If you are the owner of a visual and believe we are using it without permission, please contact us—we will reply promptly and make things right.

Exploration
blind man by TommyEdisonXP , used under CC BY
cat in window by Chris Lattuada , used under CC BY / Heavily modified
glasses by Michelle Arseneault , used under CC BY-SA / Adjusted color, cropped
cow by Peggy Greb
Activity
race car by The Tire Zoo , used under CC BY
light switch by Derek Gavey , used under CC BY-SA
man standing in front of curtains by Maegan Tintari , used under CC BY-SA
Other
Unit: brown eye by Giulia Marotta , used under Public Domain
Lesson narration:

Activity Prep

Print Prep

In this lesson, students discover the basics of how their eyes work, and figure out some of the causes of vision problems. In the activity, Eye Model, students develop a working model of a human eye. They use a magnifying lens as a model of the cornea to explore how the structure of this lens is related to the function of our eyes.

Preview activity

Exploration

21 mins

Wrap-Up

4 mins

Extend this lesson

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