1. Unit 33 - Optics Optics is the study of the behavior and properties of light. This includes it’s interactions with objects including mirrors, lenses, and substances which reflect or scatter light.
2. When Light Strikes an Object When light strikes an object, the light can be reflected, transmitted, scattered, or absorbed.
8. Incident ray = the incoming ray that approaches the mirror
9. Angle of incidence = the angle the incident ray makes wit a line drawn perpendicular to the surface of the mirror.
10. Reflected ray = the ray the mirror reflects from the incident ray.
11. Angle of reflection = the angel the reflected ray makes with the perpendicular line. Plane mirror
12. - Reflection and Mirrors Concave Mirrors A mirror with a surface that curves inward like the inside of a bowl is a concave mirror.
13. Parabolic Mirrors They can reflect the light to a focal point, making it the strongest signal possible. Satellite dishes direct the radiowaves to the antenna which sits at the focal point Parabolic mirrors direct sunlight to a focus to absorb energy and generate electricity.
17. Convex Mirrors A mirror with a surface that curves outward is called a convex mirror.
18. Comparing and Contrasting As you read, compare and contrast concave and convex mirrors in a Venn diagram like the one below. Write the similarities in the space where the circles overlap and the differences on the left and right sides. Concave Mirror Convex Mirror Real images Virtual images Curves outward Enlarged images Reduced images Curves inward
19. Quick Lab – everyone go get a spoon!!! Situation 1 Grab a spoon and hold it close to your face so the back side of the spoon is toward your face, as shown in Figure 33.1.4. Observe your image in the spoon and slowly move the spoon away from your face. What do you observe? Is the spoon acting as a concave or convex mirror in this situation?
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23. When the object is outside the focal point, the image becomes a real image and it is inverted.
24. A real image means that a screen could be placed there and the image would appear.
27. - Refraction and Lenses Lenses A lens is a curved piece of glass or other transparent material.
28. Lenses An object’s position relative to the focal point determines whether a convex lens forms a real image or a virtual image.
29. Lenses A concave lens can produce only virtual images because parallel light rays passing through the lens never meet.
30. Asking Questions Question Answer When does refraction occur? When light rays enter a medium at an angle What are the types of lenses? Concave and convex lenses
31. Light entering the eye first enters through the cornea, where it is refracted and begins to focus the light through the pupil. The pupil will expand during times of low light in order to allow more light to enter the eye. During times of bright light it will contract. When the pupil contracts, the iris gets larger and when the pupil expands, the iris gets smaller. After light passes through the pupil it then enters the convex lens in your eye. This lens focuses the light onto the light sensor cells on the back of your eye called rods and cones which are collected at the retina. The area where the nerve endings come together to form the optic nerve create a blind spot.
32. Correcting Vision Concave lenses are used to correct nearsightedness. Convex lenses are used to correct farsightedness.
34. Sequencing How You See Objects Light enters the eye. Light focuses on the retina. An image forms. Rods and cones send signals to the brain.
35. - Using Light Optical Instruments A telescope forms enlarged images of distant objects. Telescopes use lenses or mirrors to collect and focus light from distant objects.
36. - Using Light Optical Instruments A telescope forms enlarged images of distant objects. Telescopes use lenses or mirrors to collect and focus light from distant objects.
37. Optical Instruments A microscope uses a combination of lenses to produce and magnify an image.
38. - Using Light Optical Instruments The lens of the camera focuses light to form a real, upside-down image on film in the back of the camera.
39. - Using Light Lasers Laser light consists of light waves that all have the same wavelength, or color. The waves are coherent, or in step.
40. - Using Light Optical Fibers The floodlight in the swimming pool gives off light rays that travel to the surface. If the angle of incidence is great enough, a light ray is completely reflected back into the water. This complete reflection of light by the inside surface of a medium is called total internal reflection.
41. - Using Light Optical Fibers Optical fibers can carry a laser beam for long distances because the beam stays totally inside the fiber as it travels.
