Welcome to a power point presentation on LIGHT.

• We will investigate the following:• 1. What is light?• 2.What are some sources of light around us?• 3. What are opaque, transparent, & translucent objects?• 4. What is a light wave?• 5.Are there any hands-on/minds-on activities I can

do to learn more?

Light

• Our primary source of light is the sun.• Light travels in straight lines at a speed of

186,000miles per second.• *Light waves travel faster than sound waves!• Light energy from the sun travels through space ,

reaches earth, and some of it turns to heat energy and warms the earth’s air.

• Light from the sun also travels to the cells of green plants (producers) and is stored as energy.

• When light reaches an object, it is absorbed, reflected, or passes through it.

Sensing Light• Humans have two

light detectors.• Do you know what

they are called?

Sources of Light

• SUN• Fire• Lightning• Firefly• Flashlight• Light bulb• Laser beams• Optical telephone fibers*Traffic lights *AIMS: Primarily Physics:

Light Sources Activity

“Just Passing Through:” What happens when light strikes

glass? Or waxed paper? Or a book?

• If light travels through an object it is =transparent

• If light is blocked by an object and a dark shadow is cast it is= opaque.

• If some light passes through but not all and a light shadow is present it is=translucent.

Transparent objects:

• The windows on a school bus,• A clear empty glass,• A clear window pane,• The lenses of some eyeglasses,• Clear plastic wrap,• The glass on a clock,• A hand lens,• Colored glass…• ALL of these are transparent.

Yes, we can see through them because light passes through each of them.

Translucent objects• Thin tissue paper,• Waxed paper,• Tinted car windows,• Frosted glass,• Clouds,• All of these materials

are translucent and allow some light to pass but the light cannot be clearly seen through.

Opaque objects:

• Heavy weight paper,• Cardboard• Aluminum foil,• Mirror, bricks, buildings,• Your eyelids and hands,• Solid wood door,• All of these objects are

opaque because light cannot pass through them at all.

• They cast a dark shadow.