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Lens Technologies. Microscopes. Invented by Johannes and Zacharias Jansen in 1590 Larger inverted image Used in study of cells and diseases. Refracting Telescopes: Galileo and Kepler. Reflecting Telescope: Newton’s Innovation. Reduced chromatic aberration. Modern Telescope.

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Presentation Transcript
microscopes
Microscopes
  • Invented by Johannes and Zacharias Jansen in 1590
  • Larger inverted image
  • Used in study of cells and diseases
modern telescope
Modern Telescope
  • http://www.youtube.com/watch?v=0jPE7u3bz_E
binoculars
Binoculars
  • Two refracting telescopes
  • Total internal reflection
  • Longer light path results in better magnification
structure human eye
Structure – Human Eye
  • Cow Eye Dissection - http://www.youtube.com/watch?v=hZ4mUMsMfTQ&feature=related
focussing human eye
Focussing – Human Eye

Ciliary muscles make the lens shorter and thicker to focus a nearby object

Relaxed eye lens focusses on a distant object

correcting vision using lenses
Correcting Vision Using Lenses

Common causes of poor vision:

  • Incorrect shape of eyeball
  • Incorrect shape of cornea
  • Hardening of the lens

Corrected by:

  • Glasses
  • Contact lenses
  • Laser eye surgery
myopia near sightedness
Myopia – Near Sightedness
  • Long eyeball results in image formation in front of the retina
  • Rays spread again and result in blurry image
hyperopia far sightedness
Hyperopia – Far Sightedness
  • Short eyeball results in reaching of light rays at the retina before they converge
  • Blurry image
presbyopia
Presbyopia
  • Symptoms often like Hyperopia (far sightedness)
  • Aging causes ciliarymuscles to be less flexbile and can no longer make the lens change shape to focus on objects at different locations
  • Solution is bifocals.
astigmatism
Astigmatism
  • Cornea is oval shaped instead of spherical.
  • Causes light to focus on two or more spots.
night vision devices
Night Vision Devices
  • You tube rescue with Night Vision Aid (40 sec. long)

http://www.youtube.com/watch?v=u-6Vd1gc8AA

  • You tube night vision goggles (3 minutes long) http://www.youtube.com/watch?v=BOpJzH0XX-c
animated optical illusions
Animated Optical Illusions
  • http://www.youtube.com/watch?v=lvvcRdwNhGM
  • http://www.youtube.com/watch?v=T5xtRdLOopU
i speye activity homework
I “Speye” Activity & Homework
  • p. 514 - Complete Part 1 – 3 with a partner
  • p. 511 # 4, 5 and 8