I'd like to say a special thank you to Schuma for this week's questions about the I.

I would also like to thank James, Jay, Stephen, Elsie, Druva, Ivy, and we're sending in questions for our next episodes of Sleeptight Science.

You're listening to Sleep Tight Science.

You're listening to Sleeptight Science. Did you know the human eye blinks between 15 and 20 times a minute?

What?

That means you blink up to 1,200 times per day and over 10.5 million times a year.

Wow! How do you see things?

When you see something, you are really seeing the light

that has bounced off of the object,

which has entered your eyes.

Light enters our eyes through the small black part of our eye, or the pupil.

The pupil can change size, which controls how much light gets in.

The iris, which is the colored part around the pupil, is a muscle which helps the pupil to dilate or open or constrict, close.

So if a light is too bright, the iris will help the pupil to constrict or close

and let less light in. If the light is not bright enough, the iris will help the pupil to

dilate or open up and let more light in.

After the light has passed through the pupil and has entered our eye, it goes through some liquids or fluids until it reaches the retina at the back of our eye.

The front part of our eye is curved,

and this makes the light bend,

so the image appears upside down on the retina.

The retina helps our brain by turning the light into a signal that the brain can recognize.

The retina gets some help changing the light from the light sensitive rods and cones.

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