1. Light
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2. Section 1 - Light and Color
When light strikes an object, the light ca be reflected, transmitted, or absorbed.
Transparent - a material that transmits most of the light that strikes it
Translucent - a material that scatters light as it passes through
Opaque - a material that reflects or absorbs all of the light
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3. Light and Color
The color of an object depends on the object’s material and the color of the light striking the object.
Every object absorbs some wavelengths of light and reflects others.
The color of an opaque object is the color of the light it reflects.
The color of a transparent or translucent object is the color of the light it transmits.
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4. Light and Color
Primary colors – three colors that can combine to make any other color
red, green , blue
Secondary colors – produced when two primary colors combine in equal amounts
magenta, yellow, and cyan
White light – produced when the three primary colors are combined in equal amounts.
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5. Light and Color
Complementary colors – any two colors that combine to form white light.
Pigments – colored substances that are used to color other materials
As pigments are added together, fewer colors of light are reflected and more absorbed.
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6. Section 2 - Reflection and Mirrors
light rays represent light waves as straight lines
The two ways in which a surface can reflect light are regular reflection and diffuse reflection pg.618
Regular – when parallel rays of light hit a smooth surface
Diffuse - when parallel rays of light hit a bumpy or uneven surface
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7. Reflection and Mirrors Plane Mirror
Plane mirror – a flat sheet of glass that has a smooth, silver-colored coating on one side
image - copy of an object formed by reflected or refracted rays of light
produces a virtual image
right side up
the same size as the object being reflected
behind the mirror
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8. Reflection and Mirrors Concave Mirrors
Surface curves inward like a bowl
used for make-up mirrors
Optical Axis – an imaginary line that divides a mirror in half (equator)
Focal Point – the point at which rays parallel to the optical axis meet.
Ray Diagram
Forms either a virtual image or real image (pg. 621)
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9. Reflection and Mirrors Concave Mirrors
Real Image – forms when rays actually meet
Upside down
Larger or smaller than the object
Image
Real - farther than the focal point
In front and upside down
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10. Reflection and Mirrors Concave Mirrors
Image (Cont’d)
Virtual - Closer than the focal point
Behind and upright
At the focal point - no image is formed
Forms parallel light rays
Headlights
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11. Reflection and Mirrors Convex Mirrors
Surface curves outward.
Forms a smaller virtual image (pg. 622)
used for security or blind spots on roads
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12. Section 3 - Refraction and Lenses
When light rays enter a medium at an angle, the change in speed causes the rays to bend, or change direction
Two images in fish tank
index of refraction - a measure of how much a ray of light bends when it enters that material (pg. 624)
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13. Refraction and Lenses Prisms and Rainbows
Longer wavelengths (red) refracted less
Shorter wavelengths (violet) refracted more
Separates the colors of white light
mirage - an image of a distant object caused by refraction of light (by hot air)
Lens – a curved piece of glass or other transparent material that is used to refract light
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14. Convex lens Thicker in the center than at the edges
parallel light rays are bent towards the center of the lens (pg. 626)
forms virtual or real image dependent upon position relative to the focal point
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15. Concave lenses Thicker at the edges than in the center
parallel light rays are bent away from the center of the lens (pg. 627)
forms virtual image (again because rays can never meet)
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16. Section 4 - Seeing Light
You see an object when a process occurs that involves both your eyes and your brain.
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17. Section 4 - Seeing Light Eye picture pg. 631 cornea - pupil - iris -
lens -
retina -
optic nerve -
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18. Seeing Light nearsighted - can see close objects clearly
eyeball too long.
corrected with concave lens
Farsighted - can see far away objects clearly
eyeball too short.
Corrected with convex lens
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19. Section 5 - Using Light Optical Instruments
Telescope uses lenses or mirrors to collect and focus light from distant objects.
Images are upside-down
Refracting telescope
Objective
Eyepiece
Reflecting
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20. Using Light Optical Instruments
(Light) Microscope – uses a combination of lenses to produce and magnify an image
Camera – use a lens to focus light to form a real, upside-down image on the back of the (film) camera
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21. Using Light
Lasers
Light amplification by stimulated emission of radiation
Laser light consists of light waves that all have the same wavelength, or color. The waves are coherent, or in step.
Uses
Compact discs
Holography
Surgery
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22. Using Light
Optical Fibers – long, thin strands of glass or plastic that can carry light for long distances without allowing the light to escape.
Total internal reflection – complete reflection of light by the inside surface of the medium
Medicine
Communication
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