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Supplies:. Print:. 10. Demo:. Warm-Up Exercise. A mirror reflects an object at a distance of 10 cm with an image that is 18 cm away. Where is the focus? What is the radius of the circle? An object is 20 cm tall and is magnified to 57 cm tall. What is the magnification?

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Demo:

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  1. Supplies: Print: 10 Demo:

  2. Warm-Up Exercise • A mirror reflects an object at a distance of 10 cm with an image that is 18 cm away. • Where is the focus? • What is the radius of the circle? • An object is 20 cm tall and is magnified to 57 cm tall. What is the magnification? • Solve the following: • 4x105 + 2.3x10-3 • BONUS :Is there something “more” to this scene? 

  3. Optics • Tomorrow: • QUIZ, Ray Diagrams • Drawing and labeling Ray diagrams • Refraction • Concepts of mirrors, SALT • Magnification and focal lengths • LESSON: • The Eye • Eye tests • Classwork

  4. An ophthalmologist is a physician who specializes in eye care

  5. Dominant Eye Test • Extend both hands forward of your body and place the hands together making a small triangle (approximately 1/2 to 3/4 inch per side) between your thumbs and the first knuckle. • With both eyes open, look through the triangle and center something such as a doorknob or the bullseye of a target in the triangle. • Close your left eye. If the object remains in view, you are right eye dominant. If your hands appear to move off the object and move to the left, then you are left eye dominant.

  6. The Amsler Grid(Tests for age-related macular degeneration – AMD) • Stand 12 inches to 14 inches away (generally a comfortable reading distance). • If you wear glasses, keep them on. • Cover one eye and look at the dot in the center of the grid. • Watch for: • Distortions or breaks in the lines of the grid. • Disappearing of lines • Blurring or grey areas • Distortion or wavy lines • Holes or spots in any areas of the grid

  7. The Snellen Chart • An eye chart used to measure visual acuity • Named after the Dutch ophthalmologist Herman Snellen (1862) • Uses combinations of 10 letters • (Ensure the top letter is 88.7 mm tall) • Viewers read from 20 feet away

  8. Reading a Snellen Chart

  9. The Human Eye

  10. Cornea • The outer surface of your eye • Transparent layer of tissue • Contributes 65-75% of the eye’s total focusing power

  11. Pupil • a hole that allows light to pass through the eye • Enlarges in the dark or when stimulated

  12. Iris • It is created by the circular band of muscle. • Determines your eye color • The iris controls the size of the pupil

  13. Retina • It is the inner lining in the back of the eye and is a projection screen for the light entering your eye

  14. Detecting Light

  15. Do Eyes Change Shape? • What type of lens is in front of your eye? • This convex lens is attached to a tiny circle of muscles that can adjust its shape • Why do aged people lose their vision?

  16. Laser Eye Surgery • Two main types of corrective eye surgery:

  17. Finding your Blind Spot A O X • Your face should be very close to the screen. • Cover right eye and focus the left eye on the X. • Now slowly move away /toward from the screen. • The O will disappear, while the A which is further to the left is still visible. As you move further away, the O will reappear. (Observe that you do not see a hole. Instead of the O you see a uniform grey background. The "hole" is filled in by your brain. Make sure there is not a glare on the screen as it will obscure the whole vision.)

  18. Vision Problems

  19. Color Blind TestWhat do you see?

  20. Color Blind TestWhat do you see?

  21. Color Blind TestWhat do you see?

  22. Color Blind TestWhat do you see?

  23. Color Blind TestYou should see one or more pictures at the right 

  24. Color Blind TestYou should see one or more pictures at the right 

  25. Color Blind TestWhat do you see?

  26. Color Blind TestWhat do you see?

  27. Colour and Vision • Most people who are legally blind are able to see some light • Colour blindness • The ability to only see shades of grey. • It occurs in 1 in 40,000 people. • The ability to see some colour but not others.

  28. Review

  29. Class Work • Pg. 481 #1,5,7,8,12,14

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