Concave and Convex Mirrors and Lenses
Light rays can be reflected
off opaque surfaces (surfaces that you cannot see through). If the surface
is smooth enough, the reflected light will produce an image as mirrors
do. A mirror can be flat or curved. A mirror that curves inward like the
inside of a bowl is called a concave mirror. Concave mirrors reflect
light rays towards a central point and produce images that can be upside-down
or right side up depending on how far away the object is from the mirror.
The reflected images can be smaller than the actual object or larger. A
mirror that bends outward like the a dome is called a convex mirror.
It spreads light rays apart. The reflected images will always be right
side up and smaller than the actual object.
Light rays are refracted as they pass through translucent objects (objects like windows that you can see through). Light is refracted when it passes through a new medium at an angle. Just as convex and concave mirrors produce different images, concave and convex lenses also produce different images than we would normally see. A concave lens is thicker at the edges than in the middle. It spreads light rays apart producing an image smaller than the actual object. Nearsighted people (people who see close objects fine but distant objects appear blurry) have concave lenses in their glasses to correct their vision. A convex lens is thinner at the edges and thicker towards the center. Convex lenses are bent towards a central point. Like a concave mirror, when a convex lens is held close to your eyes, it will produce an upright image. If it is held away from your eyes it will produce an upside-down image. Farsighted people (people who can see distant objects with no problem but objects very close to them appear blurry) use convex lenses in their eyeglasses. Convex lenses can produce images much larger than the actual object. A magnifying glass is an example of a convex lens.
Part One: Fill in the blank with either convex or concave.
1. A _________________ mirror curves inward.
2. A _________________ lens is thicker in the middle than at the edges.
3. The image from a _________________ mirror will always appear smaller than the actual object.
4. A lens that spreads light rays apart is a _________________ lens.
5. In a Fun House, a mirror that makes you look upside down would have
to be a ______________ mirror.
Part Two: Fill in the blank with the appropriate word from the word
1. Light rays are _______________ when they hit a mirror.
2. A magnifying glass is an example of a _______________ lens. It can make objects appear bigger than they actually are.
3. Light rays are ________________ when they go through a lens.
4. A ________________ mirror can produce an image that appears larger than the actual object.