Tuesday, May 24, 2016

Cow Eyes?!

For this science experiment, mom & I bought some cow eyeballs from a butcher. I already studied the anatomy of an eye online, so this was an experiment to get a bit more physical! 

First we pulled away some of the meat and checked out the two eyeballs from the outside - gross! When we cut open the first eyeball, all the vitreous humour (the liquid that fills most of the eyeball) came spilling out onto the table. We turned the front half of the eye inside out and saw the iris, the pupil, and the cornea.  Interestingly, the cornea was very thick. It took me ten tries with a pair of sharp kitchen scissors to cut it fully in half! As we turned the front half of this eyeball inside out, the lens fell out with a sound like Jell-O falling off a spoon and hitting the floor - a clear BLOB!

The iris was very beautiful, but the lens was hilarious! Like a raw egg white, it oozed everywhere and was impossible to pick up! We placed the lens on top of a K we wrote on a piece of paper and the lens magnified it. We had fun trying to hold on to its slippery edges and look through it. Unfortunately, we bought the eyes frozen and not fresh, therefore making the lenses a little cloudy. The once-frozen state of the eyes became apparent when I found a bit of the lens that was still hard!

The vitreous humour was a blackish liquid that looked like muddy pond water and spilled everywhere! The retina was on the back of the eye and the point where the knife is at is the blind spot. The back of the eye is lined with photoreceptors called rods and cones. Rods are responsible for vision when there isn't much light, and cones help us see patterns and colours. The blind spot is the place where there are no rods or cones, because the optic nerve enters the eye there.
Everybody has a different blind spot, and you can find yours by doing this:

Take a sheet of paper, draw an X in the middle and a dot to the right, on the same line. Focus on the X and pull the sheet of paper closer to your face. At one point you will see the dot disappear. That's your blind spot!

All in all, the experiment was both yucky and fun! I liked handling the different parts of the eye (with gloves). It's a whole different experience seeing the parts of an eye on a computer and seeing them for real!

1 comment:

  1. Glad you enjoyed this. Very interesting indeed.
    Natural hands on is still the best way to understand things. Thank You for sharing. Love Nanny & Papa