«Cow Eye Dissection Follow light on its journey through the eye. In this very hands-on classroom workshop students will pair up to perform cow eye ...»
Cow Eye Dissection
Follow light on its journey through
the eye. In this very hands-on
classroom workshop students will
pair up to perform cow eye
dissections and gain a deeper
understanding of the human eye.
Recommended Grade Level 6-10
Cow Eye Dissection
Standard 5.1.C: Reflect on Scientific Knowledge
Standard 5.1.D: Participate Productively in Science
Standard 5.3.A: Organization and Development
By the end of the presentation, the audience will know and be able to:
The anatomy and physiology of the cow’s eye The functions of each structure of the cow’s eye The similarities and differences between a cow’s eye and a human eye How vision works
In this program students will investigate a cow’s eye which is has similar structures to a human eye. Students will dissect a cow’s eye and examine each structure of the eye and relate it to their own eyes.
See equipment requirement next page Thank you for reserving…Cow Eye Dissection
There are just a few things we will need:
Safe, legal parking with easy access to our vehicle must be provided.
This program requires a regular-sized classroom with one large table set up for our materials and work surfaces for students (they will work in pairs). Please be advised that this space must be available to us 45 minutes prior to the scheduled start time for set-up and 30 minutes following the conclusion for breakdown.
If this program has been booked for more than one class we would prefer that the equipment stay in one room and that the students rotate to us.
(For safety reasons, we cannot have students in the area while we are engaged in the set-up or breakdown of programs.)
A television monitor with video hook-up is required for this presentation.
We bring all of the necessary supplies for the dissection: the eyes, the trays, the dissecting kits, rubber gloves, goggles and cleaning supplies.
Please have extra paper towels and soap for students so they can wash their hands.
The audience size is limited to a maximum of 30 per workshop.
5. Directions If you know that online directions to your location are inaccurate, please see the next page.
Please contact us at 201.253.1310 if any of these outlined criteria present an issue.
Our Traveling Science Educators normally use MapQuest for directions. Most times the
directions are accurate. However:
If directions from online services to your venue are inaccurate or difficult to understand please use this form to clearly print or type directions to your location.
If there are any special instructions we must follow once we get to your location please note them below.
Please use this form only. Do not substitute!
Estimated driving time from Liberty Science Center: _____ Hours _____ Minutes To ensure our timely arrival, we MUST know how long it takes to reach you.
Directions (Must start from Exit 14B of the N.J. Turnpike or the Holland Tunnel):
This packet contains some simple classroom activities utilizing everyday, inexpensive (or even free!) items. Please feel free to duplicate these pages as needed - they are sent on plain white paper to ensure the best quality of reproduction.
We suggest that these activities be conducted before our visit in order to familiarize students with some of the concepts we will explore together during our Cow Eye Dissection presentation. However, they may be performed after our visit to serve as a reinforcement of the concepts covered in the program. If and when you choose to use these activities, or whether or not the activities are appropriate for your class, is entirely at your discretion.
If you have questions about any of the enclosed activity procedures, please contact our Science Educators Associate Director at: 201.253.1472
Stereovision or binocular vision is the use of two eyes to see one picture. We perceive depth by a mental interpretation of what our two eyes see. Each eye gets a slightly different picture of the same object and those two pictures give the brain depth cues.
Binocular vision is another term that means 3-D vision. The word binocular means two eyes. Your 3-D vision helps you walk down steps, pick up a telephone or shake someone’s hand. Two eyes help you to see in 3-D. Since your eyes are about two inches apart, each eye sees a slightly different view. Your brain combines the views from your two eyes so you can see things in 3-D.
Close one eye. Hold your thumb an arm’s-length away from your body. Line up your closed eye with your thumb and cover something up with your thumb. Now switch eyes.
Did it look like your finger moved? That’s because your eyes are about two inches apart and each eye sees a slightly different view.
Find a shiny metal spoon or ice cream scooper in the kitchen. Hold it up to one eye.
What do you see? You should see a reflection of your eye and the space behind you.
What is odd about that picture? Everything is upside down! The concave spoon flips the image over.
Roll a sheet of paper into a tube. Hold it up to your left eye like a telescope. Hold your other hand about four inches away from your face. Keep both eyes open. If you position everything correctly, your hand will seem to have a hole in it.
Two eyes are not always better than one. Sometimes two images can produce a rather muddled picture of reality. However, your brain has learned to ignore conflicting images so you ―see‖ an edited version of the message your eyes send to your brain.
1. Hold one pencil in each hand horizontally facing each other at an arm’s-length away from your body.
2. Close one eye and try to touch the tips of the pencils together.
3. Now try it with two eyes. You should see that it is easier to get the tips to touch when using both eyes.
Cup (a yogurt or drinking cup) Objects to drop (pennies, buttons or paper clips)
1. Collect a set of pennies (buttons or paperclips) and pair up with a partner.
2. Person #1 will sit at the table with the cup about 2 feet in front of them on the table. This person closes one eye.
3. Person #2 holds a penny about 1.5 feet above the cup and moves the penny slowly around.
4. Person #1 says ―Drop it!‖ when they think the penny will drop into the cup.
5. When person #1 says ―Drop it!‖ person #2 will drop the penny and see if it makes it into the cup.
6. Try it again with both eyes open.
7. Try it again with the cup farther away and then closer. Compare the results of 10 drops at each distance.
Keep your Eye on the Ball
Ping-pong ball Eye patch
1. Have two students throw the ping-pong ball back and forth 15 times with both eyes open.
2. One student should close one eye and throw the ball back and forth another 15 times, then switch.
3. Keep track of how many times the ball is dropped. (Try catching with just one hand if this is too easy!)
Students should see that two eyes are better than one when it comes to depth perception after trying all three of these activities.
Peripheral Vision Your side vision is called peripheral vision. It’s the blurry shapes you see from the corner of your eye. You can easily test how clearly you see with your peripheral vision.
Clay or Plasticine balls Pieces of colored paper (red, yellow, blue, black, white and green)
1. Open your arms behind you and move them slowly forward. Stop when your fingers come into view.
2. Drop some clay balls as markers. This marks your wide angle vision. Is there any difference if you repeat step one with wiggling fingers?
3. Now test your peripheral color vision. Have a friend hold up pairs of colored squares at the place where you marked your wide angle vision. Use paper squares of red, yellow, blue, black, white and green. Which do you see first? Do you see colors in any particular order? Is your peripheral vision just as good at detecting colors as it is at detecting motion?
What’s going on?
Your retina (the light-sensitive lining at the back of your eye) is packed with lightreceiving cells called rods and cones. Only the cones are sensitive to color. These cells are clustered mainly in the central region of the retina.
When you see something out of the corner of your eye, its image focuses on the periphery of your retina, where there are few cones. It isn’t surprising that you can’t distinguish the color of something you see out of the corner of your eye.
The rods are more evenly spread across the retina, but they also become less densely packed toward the outer regions of the retina. Because there are fewer rods, you have a limited ability to resolve the shapes of objects at the periphery of your vision.
In the center of your field of vision is a region where the cones are packed closely together. This region is called the fovea. This surprisingly small region gives you the sharpest view of an object. The fraction of your eye covered by the fovea is about the same as the fraction of the night sky covered by the moon.
Your peripheral vision is very sensitive to motion – a characteristic that probably had strong adaptive value during the earlier stages of human evolution.
Find Your Blind Spot The retina consists of a layer of tissue on the back portion of the eye that contains photoreceptor cells that are responsive to light. The retina’s function is to convert the light into electrical signals that are later sent down the optic nerve to the brain. The blind spot is where the retina is attached to the optic nerve. The blind spot is insensitive to light because there are no light sensing photoreceptor cells located there. The two different views that your right and left eye see compensate for the blind spot of the other eye. This activity will help you find your blind spot.
Materials: 3 x 5 index card Pen
1. Draw an X in the left hand corner of the index card and a dot in the right hand corner.
2. Hold the card at an arm’s-length away and close your left eye.
3. Stare at the X. be sure not to look at the dot with your right eye.
4. Slowly bring the index card closer to your face while staring at the X.
5. When the dot is no longer visible, it is being focused on your blind spot.
How the Eye Adjusts to Light The iris, the colored part of the eye, is actually a muscle. This muscle is used to regulate the amount of light that enters the eye through the pupil. In this activity, students will observe that the level of light in the room affects the size of the pupil.
Materials: Pen light
1. Divide students in groups of two and give each pair a pen light.
2. Dim the lights and sit for two or three minutes.
3. One student in each pair should be the observer. Ask them to observe the size of the other student’s pupil.
4. Starting at the side of the face, the observer should slowly shine the pen light across the eye of the other student. The light should shine into the pupil, but not for more than a second.
5. Compare the size of the pupil before and after shining the light in the eye.
Students should notice how the pupil reacts to the dim and bright lights. The pupil gets larger in the dim room to allow more light to enter the eye. However, it shrinks when exposed to the pen light to keep too much light from entering the eye.
Colorful Eyes The color of the iris is genetically determined. Pigment called melanin can be found in the iris. This pigment gives the eye color. Brown eyes have lots of pigment; blue eyes have very little.
The amount of pigment is determined by a number of genes controlling pigment production. Generally speaking, brown is dominant, meaning that if one parent has brown eyes and the other has blue eyes, their baby will most likely have brown eyes.
This activity will help students make their own predictions about the dominant eye color in their classroom.
Paper to make a prediction chart and an eye color chart Different colored markers or stickers to represent blue, brown, green and hazel eyes Mirror
1. Create a prediction chart by drawing a table with four columns. Label the columns blue, brown, green and hazel.
2. Ask each student to predict which eye color they think will be found most often in the class. Keep track by placing an eye marker (a sticker, a tally mark, etc.) in the appropriate column.
3. Create another chart like the prediction chart, but this time it will be the eye color chart.
4. Have students take turns looking into the mirror to determine their eye color. Ask them to place an eye marker in the corresponding column on the eye color chart.
Compare the prediction chart and the eye color chart. How accurate was the original prediction? If the same activity were conducted with another class, would the majority of the students have the same eye color as the majority of students in your class? Why or why not?