Unit C Flashcards
Famous names of discoveries and optical ideas?
Archimedes - Planned for the use of mirrors in war.
Pythagoras - Thought light was beams of light coming from our eyes.
Euclid - Thaought that light was reflected, and that light travels in straight lines.
Ptolemy - Thaought that light bends when it travels from air to glass.
AI-Haythem - He wrote a book to help explain optics, being the first to accurately describe how visin worked.
Isaac Newton - Invented the reflecting telescope. and also showed that white light is a mixture of different colors of light.
Ole Romer - Determined the speed of light.
Albert A. Michelson - He was able to determine more accuratliy the speed of light.
Properties of light?
what are the 4 properties of light?
1) Light travels in straight lines.
2) Light can be reflected.
3) Light can be bent.
4) Light is a form of Energy.
Optical devices (telescopes, binoculars, microscopes)–>how do they work and what do they help us with?
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Telescopes:
1. * Telescopes both magnify and they also collect light.
2. It proides enlarged mages of distant objects using lenses and Mirrors.
3. There are 2 main typesof telescopes:
-Refracting telescopes
- Reflecting telescopes -
Binoculars:
A parallel combination of two telescopes for viewing an erect image with both eyes. -
Microscopes:
1. A Microscope device which allows for the viewing of Very small objects.
- Has two lenses
- Objective
- Eyepiece
- When these 2 lenses are combined, you are then able to see in great details.
For Binoculars: Because they are designed so that an image of the same size can be viewed with both eyes, users can observe objects more comfortably than with a single eye.
Luminous vs. Nonluminous?
Luminous: produces light.
ex) lamp, sun.
Non-luminous: Dose not produce light.
ex) pencil.
Opaque vs. Translucent vs. Transparent?
Opaque: Absorbs or reflects the light.
ex) A Brick.
Translucent: It allows some of the light to pas through it.
ex) A frosted window.
Transparent: Light travels straight through it.
ex) Glass.
Labeling parts of a ray diagram?
Regular vs. Diffuse reflection?
Regular Reflection:
-Light rays hit a smooth surface.
-Travel PARALLEL.
-Reflect at opposite angle.
-Produces a clear image.
Diffuse reflection:
-Light rays hit a rough surface.
-Light becomes scattered.
Mirrors : converging and diverging?
Diverging=Convex mirror
Converging=Concave mirror
Converging Mirrors:
*Cave in
*Image appears to be closer than it actually is.
*Focal point is in front of mirror.
*Rays come together→ converging rays.
*Reflects light from a large area:
- Flashlights
- Telescopes
- Cosmetic mirrors
Diverging Mirrors:
*Bulge out.
*Rays spread out→ diverging rays.
*Image appears much smaller and farther away than the object.
*Can reflect light from a large area.
*Focal point is in behind mirror:
-Rear-view mirrors
and side mirrors on cars.
Concave and Convex lenses –>what do they look like, how does light react with them?
Concave Lenses:
-Thinner in the center than at the edges.
-Parallel rays are refracted away from the center of the lens (spread out).
Convex Lenses:
Curves outward and is thicker in the middle than at the edges.
Parallel light is refracted toward the center of the lens (cross over at focal point).
Reflection vs. Refraction→what is the difference, why and how do both happen?
Reflection: Light strikes a surface and bounces back off that surface.
Refraction: the bending of a ray when it passes at an angle from one medium into another in which its speed is different (as when light passes from air into water).
Angles light reflects vs. Angles light refracts?
Angles light Reflects: on reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray. (By convention, all angles in geometrical optics are measured with respect to the normal to the surface—that is, to a line perpendicular to the surface.)
Angles light Refracts: The amount of bending that a light ray experiences can be expressed in terms of the angle of refraction (more accurately, by the difference between the angle of refraction and the angle of incidence). A ray of light may approach the boundary at an angle of incidence of 45-degrees and bend towards the normal.
Mirages→how and why are they formed?
Mirage:
-Refraction can also occur when light travels
through air at different temperatures, because
warm air is less dense than cold air.
Mirage: refraction of light through air
Label the parts of the eye and know their purpose?
Camera vs. Eye→know parts and comparisons?
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Eye:
-Photoreceptor cells in the retina detect light.
-Produce small electrical impulses from the retina to the brain through the optic nerve.
-Layers of tissue hold the different parts of the eye together.
Parts:
-Cornea, iris, lens, ciliary muscles, optic nerve, pupil, sclera, retina, vitreous humour.
-
Camera:
-The film at the back of the camera contains light sensitive chemicals.
-These change when light hits it.
-The parts of a camera are inside a hard, light-proof box.
-Digital cameras use sensors to create an image.
Parts: Film, aperture, lens, lens cap, shutter.
Rods vs. Cones→what do each do?
Rods: Rods are a type of photoreceptor cell in the retina. They are sensitive to light levels and help give us good vision in low light. They are concentrated in the outer areas of the retina and give us peripheral vision. Rods are 500 to 1,000 times more sensitive to light than cones.
Cones: Cones are a type of photoreceptor cell in the retina. They give us our color vision. Cones are concentrated in the center of our retina in an area called the macula and help us see fine details. The retina has approximately 120 million rods and 6 million cones.
