23Section 2 Reflection and Refraction of Light Light and matter – objects must reflect light to be seen.1. Opaque materials do not allow light to pass through them; they only absorb and reflect light.
24Section 2 Reflection and Refraction of Light Some light passes through translucent materials (like the light coverings in D-5).Transparent materials transmit all light, absorbing and reflecting little light.
26Section 2 Reflection and Refraction of Light Law of reflection – the angle at which light strikes a surface equals the angle at which it is reflected.1. Regular reflection-reflection of light waves from a smooth surface.
27Section 2 Reflection and Refraction of Light Diffuse reflection-reflection of light waves in many directions from a rough surface.Scattering-type of diffuse reflection that occurs when light waves traveling in one direction are made to travel in many different directions.
28Section 2 Reflection and Refraction of Light Refraction of light-change in the speed of light wave when it passes from one material to another.1. The index of refraction indicates how much a material reduces the speed of light; the more the light is slowed, the greater the index of refraction.
29Section 2 Reflection and Refraction of Light Prisms separate white light into visible spectrum based on light wavelengths.Refraction of light through air layers of different densities can result in a mirage.
36Section 3 Mirrors, Lenses and the Eye Plane mirror – flat, smooth mirror in which an image appears upright.In a concave mirror, the mirror surface is curved inward; the image depends on location of object relative to focal point.
39Section 3 Mirrors, Lenses and the Eye Convex mirrors are curved outward, diverge light rays when reflected, and show virtual images.C. Lens – transparent material with a curved surface that refracts light rays.
46Section 3 Mirrors, Lenses and the Eye Form real, enlarged, and inverted image when object is between one and two focal lengths from the lens.Form virtual, enlarged, and upright image when object is less than one focal length from the lens.
47Section 3 Mirrors, Lenses and the Eye A concave lens is thinner in the middle and thicker at the edges.D. The structure of your eye allows you to focus on objects.
49Section 3 Mirrors, Lenses and the Eye Light enters the eye through the cornea, a transparent covering on the eyeball.A convex lens helps to focus light rays to form sharp images.
50Section 3 Mirrors, Lenses and the Eye Retina – inner lining of the eye that converts light into electrical signals that the brain interprets.E. Vision problems occur when lenses in the eye do not focus images properly.
51Section 3 Mirrors, Lenses and the Eye Farsightedness – when lens is not curved enough to form an image of close objects.Astigmatism – the cornea’s surface is unevenly curved.
52Section 3 Mirrors, Lenses and the Eye 3. Nearsightedness – lens does not flatten enough to form an image of distant objects.
68While humans have three types of color-detecting cells, mice and most other mammals have just two. But when a group of scientists gave mice the human gene for a third color detector, they were able to detect colors that no mouse has ever seen before.