Download - Seeing Light
Seeing LightSeeing Light
StudStudents will be able toents will be able to
Describe parts of eyeDescribe parts of eye
Explain how vision problems occurExplain how vision problems occur
Identify uses of lightIdentify uses of light
Page 126Page 126
SightSight
Combination of eye capture light and Combination of eye capture light and brain working to understand imagesbrain working to understand images
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Parts of EyeParts of Eye
ScleraSclera
White partWhite part
Many nervesMany nerves
Clear in frontClear in front
Cornea – Help to focus light into Cornea – Help to focus light into eyeeye
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IrisIris
Eye ColorEye Color
Absorbs lightAbsorbs light
MuscleMuscle
Control PupilControl Pupil
Dilate when dark to get light inDilate when dark to get light in
Contract when bright to protect eyeContract when bright to protect eye
Important medical assessmentImportant medical assessment
Fixed and DilatedFixed and Dilated 127
LensLens
Focus lightFocus light
Ciliary MuscleCiliary Muscle
Controls shapeControls shape
Thin for farThin for far
Relaxes muscleRelaxes muscle
Thick for closeThick for close
Contracting muscleContracting muscle
Can cause eye fatigueCan cause eye fatigue127
RetinaRetina
Responds to lightResponds to light
Cone = ColorCone = Color
Rod = MotionRod = Motion
Poor designPoor design
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Optic NerveOptic Nerve
Message to brainMessage to brain
Double image isDouble image is
merged in brainmerged in brain
Needs to turnNeeds to turn
image uprightimage upright
Creates blind spotCreates blind spot
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NearsightednessNearsightedness
Can only see object that are nearCan only see object that are near
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FarsightednessFarsightedness
Can only see object that are farCan only see object that are far
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AstigmatismAstigmatism
Lens or cornea distortedLens or cornea distorted
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Using LightUsing Light
Light from Nebula took 3 million yearsLight from Nebula took 3 million years
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Optical InstrumentsOptical Instruments
TelescopesTelescopes
Use lenses to focus lightUse lenses to focus light
Big image to smallBig image to small
RefractingRefracting
Two convex lensesTwo convex lenses
Larger – ObjectiveLarger – Objective
Smaller – EyepieceSmaller – Eyepiece
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Optical InstrumentsOptical Instruments
ReflectingReflecting
MirrorsMirrors
Concave MirrorConcave Mirror
Plane MirrorPlane Mirror
Convex lensConvex lens
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MicroscopesMicroscopes
Small image and make bigSmall image and make big
Two lensesTwo lenses
Larger – ObjectiveLarger – Objective
Smaller – EyepieceSmaller – Eyepiece
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CameraCamera
Lens to focus imageLens to focus image
onto film or screenonto film or screen
DiaphragmDiaphragm
Acts like pupil to let in lightActs like pupil to let in light
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LaserLaser
FlashlightFlashlight
All colors of lightAll colors of light
LaserLaser (Light Amplification Stimulated Emission of Radiation)(Light Amplification Stimulated Emission of Radiation)
One type of lightOne type of light
Bounced by partial mirrorBounced by partial mirror
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LaserLaser
Laser UsesLaser Uses
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Laser UsesLaser Uses
HolographyHolographyPictures that appear to move when you movePictures that appear to move when you move
SurgerySurgeryCut tissue and seals blood vessels as you cutCut tissue and seals blood vessels as you cut
Much less bleedingMuch less bleedingThin tissue (lasik surgery)Thin tissue (lasik surgery)Welding (detached retina)Welding (detached retina)Destroy tissue (cancer or blemishes)Destroy tissue (cancer or blemishes)
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Optical FibersOptical Fibers
Thin strands of glass/plasticThin strands of glass/plastic
Prevent laser light from escapingPrevent laser light from escaping
Total internal reflectionTotal internal reflection
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Optical Fiber UsesOptical Fiber Uses
MedicineMedicine
Attached to camera see insideAttached to camera see inside
CommunicationCommunication
Each can carry thousands of Each can carry thousands of
phone conversationsphone conversations
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QuizQuiz
HomeworkHomework
State the three problems that can go State the three problems that can go wrong with vision.wrong with vision.
QuizQuiz
1.1. What is the clear part of the eye?What is the clear part of the eye?a.a. CorneaCornea
b.b. IrisIris
c.c. PupilPupil
d.d. ScleraSclera
QuizQuiz
2. In bright light your pupil should be…2. In bright light your pupil should be…s. Smalls. Small
l. Largel. Large
QuizQuiz
3. What causes eye fatigue3. What causes eye fatiguea. Looking at an object far awaya. Looking at an object far away
b. Looking at an object up closeb. Looking at an object up close
QuizQuiz
4. What is wrong with this eye?4. What is wrong with this eye?a.a. FarsightedFarsighted
b.b. NearsightedNearsighted
c.c. AstigmatismAstigmatism
d.d. NothingNothing
QuizQuiz
5. Which telescope uses mirrors?5. Which telescope uses mirrors?a.a. RefractingRefracting
b.b. ReflectingReflecting
c.c. Neither oneNeither one
d.d. BothBoth
QuizQuiz
6. Which part of the camera controls the 6. Which part of the camera controls the amount of light that enters the camera?amount of light that enters the camera?
a.a. DiaphragmDiaphragm
b.b. LensLens
c.c. ShutterShutter
d.d. Shutter releaseShutter release
e.e. OtherOther
QuizQuiz
7. A laser always produces…7. A laser always produces…a.a. Many wavelengths of lightMany wavelengths of light
b.b. One wavelength of lightOne wavelength of light
c.c. Red lightRed light
d.d. Green lightGreen light
e.e. OtherOther
QuizQuiz
8. Which is not a function for lasers8. Which is not a function for lasersa.a. Bar code scannerBar code scannerb.b. CuttingCuttingc.c. Reading/Writing CDsReading/Writing CDsd.d. HologramsHologramse.e. SurgerySurgeryf.f. SurveyingSurveyingg.g. Viewing starsViewing stars
QuizQuiz
9. What prevents light from escaping a fiber 9. What prevents light from escaping a fiber optic cable?optic cable?
a.a. Total external reflectionTotal external reflection
b.b. Total internal reflectionTotal internal reflection
c.c. Light does escapeLight does escape
d.d. OtherOther
QuizQuiz
10. What is not a use for fiber optics?10. What is not a use for fiber optics?a.a. MedicineMedicine
b.b. Telephone serviceTelephone service
c.c. Television serviceTelevision service
d.d. All of the aboveAll of the above