Article Diary - General Knowledge Digest

Light And Dark - where does light come from?

Where does light come from?

The Earth’s biggest source of light is the Sun. heat and light energy created by the Sun travels through space in straight lines called rays at almost 300,000 kilometers per second. The Earth spins right around once a day, changing which parts of the globe get sunlight. This creates day and night. Other things that radiate or give off, light include electric light bulbs, candles and television sets.

What are shadows?

Shadows happen in places where an object stops light from getting through. Materials that light shines through fully are said to be transparent. Translucent materials only let a little light through. Opaque materials do not let any light through at all. The shape of a shadow depends on the shape of the object blocking the light. If an object is moved closer to alight source, its shadow gets bigger because it blocks more light.

Why do mirrors reflect images?

All surfaces reflect light but, if they are bumpy, the light rays are reflected in all directions. Mirrors are pattern as they hit it, creating a clear image of any object. Words made from very smooth surfaces that reflect the rays back in the same pattern as they hit it, creating a clear image of any object. Words reflected in a mirror appear back to front, as if they were facing away from us and we were looking through the page.

Did you know?
Fireflies flash chemicals that give off light in their bodies to attract mates at night.

How do periscopes work?

Periscopes are devices that use reflecting mirror in order to see things from a lower level. An angled mirror reflects an image, made up of light, down a tube. A second angled mirror at the bottom of the tube reflects the light again to turn the image back the right way up. Periscopes are often used to see surface ships from underwater submarines or over people’s heads in crowds.

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