Concave and Convex Lenses
Refraction- The bending of light as it moves from one substance to another. Convex Lenses Characteristics: •Point is known as focal point. Concave Lenses Characteristics:
Ask students for any more examples they can think of where refraction takes place? After students start into different kinds of lenses start with this... Then, start on how lenses, a piece of material which light is able to pass through, are used to refract light. Also, explain that there are different types of lenses.
•Convex
•Concave
Convex - A lens which is thicker in the middle than on the ends.
Concave - A lens which is thinner in the middle than on the ends.
A MINI DIAGRAM OF MINE
•Refracts parallel light rays so they come together at a single point. Does anyone know what it is called when the light rays are made to come together?
-Known as convergence.
•Distance from center of lens to focal point = focal length.
•The thicker the middle of the lens the shorter the focal length.
•Example of a convex lens is a magnifier.
•Image can be seen without actually looking through the lens. This type of image is known as a real image.
•When held close to objects, inside of its focal length, it produces an image known as a virtual image. To see a virtual image you must look through the lens.
•Refracts the rays so they come apart. . Does anyone know what it is called when the light rays are made to come apart from each other?
-Known as divergence.
•Always forms a virtual image.