Optics

We started a new unit on optics last week and then were given a handout on the human eye. It included a labelled diagram that I have here:

Not sure why it's sideways..

Some important information that we took away from that handout was that:

1. The cornea causes light to bend (refract) at the surface of the eye.

2.The lens, whose shape or curvature, is controlled by the ciliary muscles and suspensory ligament, causes light to undergo even more refraction. The lens of the eye focuses light.

3. The iris located behind the aqueous humour and in front of the lens contracts or expands to change the size of the pupil. The size of the pupil is altered to let in different amounts of light.

4. The vitreous humour helps maintain the shape of the eye.

5. The white surface of the eye is called the sclerotic (sclera).

6. The retina is located at the back of the eye. It is light sensitive. The surface of the retina is where the lens focuses images to be transmitted to the brain. The retina contains different types of light-sensitive receptors called rods and cones. Rods are sensitive to dim light and do not respond to colour. Cones are sensitive to bright light and colour.

As an interesting note, all people have a dominant eye. The second eye is mainly used for depth perception.

After that we found our near point as well as our blind spot. The near point of an eye us the closest an object can be to your eye and still be clearly focused. For the average adult eye it is 25 cm although when we did ours as a class most people got numbers around 5-12 cm. The blind spot is located at the back of the eye near the optic nerve. There are no receptors located here which means that we cannot see anything on that spot.

I believe it was Thursday when we watched the cow eye dissection and if anyone is still interested in Katie's crazy antics, I have the link for the site. http://www.exploratorium.edu/learning_studio/cow_eye/

 The next handout we received was one on animal vision. We learned that dogs have a visual field of 240, and humans only have a visual field of 200 which means dogs are able to see a more broad image. This is because their eyes are located on the sides of their head and humans eyes are located on the front of their heads. Dogs cannot distinguish colours like we can because they only have 20% the photoreceptors we do. That means they can only see a limited colour spectrum.

Dogs also have a hard time seeing fine detail. The objects need to be large in order for them to see them otherwise it is all a blur to them.

Today we worked on our power point presentations which we will be showing the class tomorrow.

I don't know what's going on with the people and blogs, so..nobody has to write one ever again.
Jk Mr.Bananow, you can pick.