1. IGCSE Coordinated Sciences Y2
Topic: The Eye

2. IN
Complete this sentence poetically, scientifically, or literally: “My eyes are…”

3. The Eye! http://www.youtube.com/watch?v=gvozcv8pS3c
Cow’s Eye dissection:
udio/cow_eye/step01.html
Sheep Eye Dissection:
link to sheep eye dissection

4. Structure and function of the eye

5. The parts of the eye

6. Internal structure and functions of parts

7. Rods & Cones Rods & cones are found in the retina and receive light.
Structure
Rod shaped
Cone shaped
Function
Extremely sensitive to light, but don’t distinguish different colors
Less sensitive to light, but respond to color, producing color vision.
Distribution
Aprox. 91 million
Approx. 4.5 million
Concentrated at the fovea

8. Rods & Cones
Rods & Cones
?v=l8_fZPHasdo

9. How does vision work? http://youtu.be/LpjbOhtcD0A
1. Light reflecting off an object is the stimulus.
2. Rods & Cones convert the stimulus into an impulse which travel through cells to the optic nerve.
3. The optic nerve carries the impulse to the brain.
4. The CNS may send an impulse to an effector.

10. How the Eye Focuses link to cilliary muscle action
Link to how accommodation works

11. Accommodation
Accommodation is the process where the lens changes in curvature and brings about a change in focus.
This allows us to focus our vision at a variety of distances.
Humans gradually lose accommodation as they get older.

12. Focusing light

13. Focusing on a distant object

14. Focusing on a near object

15. How light intensity is controlled by the iris

16. Low light intensity

17. OUT/Homework
Read p
Page 158 Q3, Q4 parts b&c