|When one flips on the light switch in a dark room, the room instantly fills with light. It seems to happen all at once. This is because light travels fast- amazingly fast. The speed of light is 186,000 miles per second. Light travels so fast that the time taken by a person to blink its eyes three times, light could travel to the moon and back.
Rays of light travel in straight lines. This can be seen by making shadows. In a darkened room, shine a desk lamp or flashlight at a wall. Hold a book in front of the light. The light doesn’t bend or curve around the book. Instead, the book blocks the rays of light, which are traveling in straight line. And so the shadow of the book is seen on the wall.
The book does not let light to pass through it because it is opaque. Opaque materials block light. A wooden door is opaque. So is a metal can. Some materials are the opposite of opaque. They are transparent. Transparent materials are clear. One can see through them. They let light pass through almost unchanged. Glass and water are transparent.
What is the color of sunlight? It seems as if it has no color. But the color of the sunlight is white. The amazing thing about it is that the white light of sunshine is actually made up of all the colors in the rainbow. Using a prism can prove it.
If one holds the prism near a sunny window, the light will shine through and make a rainbow like band of colors. This shows that even though light may appear to be white or colorless, light is really made up of all colors. When light goes through a prism, the glass slows it down and changes its path. The process is called refraction. A prism refracts the light. A lens refracts the light.
A prism separates white light into the spectrum of colors. The prism bends the rays of light, but rays of each color bends differently. Red bends the least. Violet bends the most.
Raindrops in the sky refract the light, which is what causes a rainbow. When light is refracted, it often separates into a combination of colors called the spectrum. The colors of the spectrum always appear in the same order: red, orange, yellow, green, blue, indigo, and violet.
Directions: Answer the following questions.