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Nurb, just because eyeballs are the size of ping pong balls doesn't mean that they make good ping pong balls. Well, Nurb cannot be blamed for his love of scientific exploration, my dear Chloe. It is what makes him unnerved. Then can we use the eyeball to explore how an eyeball works instead. We could, but, these are kind of small and squished. One might say that. How about we take a look at him? Most excellent idea. Let's do. The eyeball is a beautiful machine, with lots of different parts working together to let you see. Poets say the eyes are the window to the soul. Well, the window to the eyeball is the cornea. A dome of clear tissue up in front of the eye that focuses light as it passes through. Oh, look at that beautiful green eye. One brown eye. One blue eye. The colourful part is called the Iris, right? Oh, yep. it's right behind the cornea. In the middle of the iris, is a black circle called the pupil, an opening that lets light into the eye. The iris has muscles attached to it that change its size, making the pupil bigger and smaller, to control how much light gets through. So, the pupil gets smaller when there is a lot of light, and, bigger, when it's dimmer. Don't look now. But, I think we're being watched. Mmmm... Ha...he blinked first... ...which is a good thing. Blinking protects and moistens the eye. Good point. So, what happens after the light has passed through the cornea and the pupil? The light passes through the lens. Like the lens in a camera? Precisely. The lens focuses the light on to the back of the eye where seeing really starts to happen. Can the lens in the eye focus on stuff that's close and stuff that's far like a camera lens would. It sure can. Let's head inside to see how. Last one through the pupils are rotten egg. The lens is held in place by a bunch of fibres which are attached to the ciliary muscles. Ciliary...Ciliary...Ciliary. The ciliary muscles change the shape of the lens to let the eye change its focus from something close by to something far away. What are you waiting for? Let's get focusing. To see something near, the ciliary muscles makes the lens thicker. To see something far, the ciliary muscles makes the lens thinner. From the lens we travel through wall retina, the back wall of the eyeball. Right, because, the lens focuses the light onto the retina. The retina has millions of light sensitive cells called Rods and Cones. About 120 million rods, and 7 million cones, in each eye. Whoa... that's a lot of rods and cones. What's the difference between them? It's the difference between black & white and colour. The rods see in black, white and shades of grey, and, help us see the shape and form of a thing. Rods also help us see in the dark. And, the cones see colour? Cones are sensitive to one of three colours; Red, Green or Blue. Together they let us see millions of colours. But, cones need more light than rods, to work well. Hey, what's this thing behind the retina? Hey, no bouncing on the Optic Nerve. it carries messages to the brain about what you are seeing. The rods and cones change the colours and shapes you see into millions of nerve messages. Then, those messages are carried along the optic nerve to the brain. It's like your eye is sending the brain a report on what you are seeing. Then your brain translates the report into cat, apple or bicycle. Or, a ping pong ball. Keep an eye on the ball there, Nurb. It's on.

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Duration: 5 minutes and 11 seconds
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Language: English
License: Dotsub - Standard License
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Views: 5
Posted by: pgtranscribes on Apr 13, 2015

Interaction-2_Video-1

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