This week in Science, we learned all about eyes.
First, we talked about the parts of the eye that we can see and about how different people’s eyes are the same and different.
Next, we each looked carefully at our own eyes to see what color our irises are:
We picked out pieces of colored paper that match our irises,
and made a class eye-color chart:
Most of the people in the class have brown eyes.
After we finished the chart, we learned about pupils (the circles in the middle of our irises).
They change size when the amount of light around us changes.
We looked very carefully at our partner’s pupils –
before and after we looked at the classroom lights:
We noticed that our pupils got larger when the room lights were turned off.
When we turned the lights on again, our pupils got smaller!
The parts of the eye that we can see are just a portion of the entire eyeball.
We guessed how large our eyeballs are.
How big is the whole thing?
Each of your eyeballs is about the size of a ping-pong ball.
The last thing we did was learn a little bit about how our eyes work.
We looked at a big model eyeball. It has a pupil and a light blue iris.
Inside the eye is a lens that looks a lot like a magnifying glass:
The lens focuses what we see onto our retinas, which are sort of like movie screens.
The most interesting part is that the pictures on our retinas are always upside-down compared to the things we are looking at!!
(Our brains flip the images back over when we process what we see.)
To help us notice this, we put a cross-arrow target in the window. The arrows pointed down and to the right.
Light coming through the window goes into the pupil and through the lens, where it gets flipped over.
If we look at the image on the retina, we can see that the arrows are pointed up and to the left.
Unfortunately, while we were doing this in class, we didn’t take any pictures.
That’s why I’m including a photo from another class.
Note that the green arrows in the window point down and to the right, while the arrows on the ‘retina’ point up and to the left:
See you (upside-down?) next week,