Key Terms: Examples: primary colors secondary color complementary colors pigment - Light and Color Building Vocabulary • Using a word in a sentence helps you think about how best to explain the word. After you read the section, carefully note the definition of each Key Term. Also note other details in the paragraph that contain the definition. Use all this information to write a sentence for each Key Term. Key Terms: Examples: transparent material Three colors that can combine to make any other color are called primary colors. A transparent material transmits most of the light that strikes it. translucent material Two primary colors combine in equal amounts to produce a secondary color. A translucent material scatters light as it passes through. opaque material An opaque material reflects or absorbs all of the light that strikes it. Any two colors that combine to form white light are called complementary colors. Pigments are colored substances that are used to color other materials.

End of Section:Light and Color

- Reflection and Mirrors Reflection of Light Rays • The two ways in which a surface can reflect light are regular reflection and diffuse reflection.

Mirror Images • A plane mirror is a flat sheet of glass that has a smooth, silver colored coating on one side. • This coating reflects an upright and same sized virtual image or something that does not really exist.

- Reflection and Mirrors Concave Mirrors • A mirror with a surface that curves inward like the inside of a bowl is a concave mirror. • The optical axis represents an imaginary line that divides the mirror in half and focal point is where the parallel light rays intersect.

- Reflection and Mirrors Concave Mirrors • Ray diagrams show where an image forms and the size of the image. The steps below show how to draw a ray diagram.

- Reflection and Mirrors Concave Mirrors • Concave mirrors can form either virtual images or real images. • Real images form when rays actually meet at the focal point, are upside down, and may be smaller or larger than the actual object. • Virtual images appears to be behind the mirror, is upright, and is always larger than the original object

- Reflection and Mirrors Convex Mirrors • A mirror with a surface that curves outward is called a convex mirror.

- Reflection and Mirrors 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

End of Section:Reflection and Mirrors

- Refraction and Lenses Bending Light • The index of refraction of a medium is a measure of how much light bends as it travels from air into the medium. The table shows the index of refraction of some common mediums.

Diamond causes the greatest change in the direction of a light ray traveling from air. Interpreting Data: Which medium causes the greatest change in the direction of a light ray? - Refraction and Lenses Bending Light

According to the graph, most solids bend light more than liquids do (quartz is an exception). Interpreting Data: According to the table, which tends to bend light more: solids or liquids? - Refraction and Lenses Bending Light

You would not expect light to bend if it entered corn oil at an angle after traveling through glycerol, because corn oil and glycerol have the same value for the index of refraction. Predicting: Would you expect light to bend if it entered corn oil at an angle after traveling through glycerol? Explain. - Refraction and Lenses Bending Light

- Refraction and Lenses Refraction of Light • When light rays enter a medium at an angle, the change in speed causes the rays to bend or change direction.

Rainbows • White light separates into different colors on entering the raindrop due to dispersion, causing red light to be refracted less than blue light.

Mirages • A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky.

- Refraction and Lenses Lenses • A lens is a curved piece of glass or other transparent material.

- Refraction and Lenses Lenses • An object’s position relative to the focal point determines whether a convex lens forms a real image or a virtual image.

- Refraction and Lenses Lenses • A concave lens can produce only virtual images because parallel light rays passing through the lens never meet.

- Refraction and Lenses Asking Questions • Before you read, preview the red headings. In a graphic organizer like the one below, ask a what, when, where, or how question for each heading. As you read, write answers to your 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

End of Section:Refraction and Lenses

Anatomy of the Human Eye

- Seeing Light Correcting Vision • Concave lenses are used to correct nearsightedness. Convex lenses are used to correct farsightedness.

- Seeing Light Sequencing • Sequence is the order in which the steps in a process occur. As you read, make a flowchart that shows how you see objects. Put the steps of the process in separate boxes in the order in which they occur. How You See Objects Light enters the eye. Light focuses on the retina. An image forms. Rods and cones send signals to the brain.

End of Section:Seeing Light

- 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.

- Using Light Optical Instruments • A microscope uses a combination of lenses to produce and magnify an image.

- 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.

- Using Light Lasers • Laser light consists of light waves that all have the same wavelength, or color. The waves are coherent, or in step.

Holograms • A hologram is a 3-D photograph created by using the light from a laser.

- 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.

- 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.

Key Terms: Key Terms: Examples: Examples: total internal reflection microscope camera laser hologram optical fiber - Using Light Building Vocabulary • A definition states the meaning of a word or phrase by telling about its most important feature or function. Carefully read the definition of each Key Term. Then write a definition of each Key Term in your own words. Key Terms: Examples: The total internal reflection is the complete reflection of light by the inside surface of a medium. A microscope is an instrument that forms enlarged images of tiny objects using lenses. telescope A telescope is a device that uses lenses or mirrors to collect and focus light from distant objects. A camera is a device that uses lenses to focus light on film to record an image. refracting telescope A refracting telescope is a telescope that uses convex lenses to focus light. A laser is a device that produces an intense beam of coherent light. objective An objective is the large lens in a telescope or microscope that gathers and focuses light. A hologram is a three-dimensional photograph created by a laser. eyepiece An eyepiece is the lens near the eye in a telescope or microscope that magnifies the image. An optical fiber is a strand of glass or plastic that can carry light long distances. reflecting telescope A reflecting telescope is a telescope that uses a concave mirror to gather light.

End of Section:Using Light

Graphic Organizer Type of Mirror Effect on Light Rays Type of Image Virtual Plane Regular reflection Concave Converge Real or virtual Convex Spread out Virtual Type of lens Effect on Light Rays Type of Image Convex Converge Real or virtual Concave Spread out Virtual

End of Section:Graphic Organizer

Table of Contents