How does your brain understand how far away something is? This experiment shows how your eyes work together to perceive distance.
Our eyes both face the same direction. Because they do, they produce slightly different views of the same object. Our brains are able to use this overlapping information (retinal disparity) to figure out how far away an object is. (If our eyes were on the sides of our heads like some animals, we would have poor depth perception.)
Try this: Close one eye and focus on a nearby object. Switch which eye is open and focus on the object again. You should see the object shift. Try it again with a faraway object. When you use just one eye, your brain can’t use feedback from both eyes to discern depth perception.
Pipe cleaners – use half for each
1. Cut your full pipe cleaner in half. Use ½ pipe cleaner for each.
2. Bend the end of a pipe cleaner so you have a circle that’s slightly bigger than a pencil. Twist it to secure.
3. Use a bit of clay to make a stand for the pipe cleaner.
4. Make 2 more pipe cleaner stands with slightly bigger circles. You should have 3 pipe cleaners on stands.
5. Test your depth perception – Place the pipe cleaner with the largest opening on a table in front of you so you cannot see the opening. Close one eye and try to put the pencil through the hole. Try it again with both eyes open. Which is easier? Try it with each sized hole and see the difference.
6. If this is too easy, try getting a needle and thread and threading the needle with one eye closed!
Based on: https://www.kiwico.com/diy/stem/anatomy-biology/seeing-depth-perception