What makes a shadow? How does a shadow appear?

Any light can shine on an object, but unless the object is transparent ,light cannot pass through the object. There is darkness behind the object where the light does not reach. That darkness is called the shadow. Look at your own shadow behind you, when you walk outside on a sunny day.

Try this activity. - Make a room dark. Put a flash of light with the help of a torch or lamp on a wall. Now hold your hand or hold a ball in front of the source of light. You will see the shadow of your hand or the ball in the lighted area. The shadow was formed because your hand/ ball blocked the light from passing through in a certain area.

There are two different kinds of eclipses:
1)Solar eclipse (Sol = Sun in Latin) – Once every one to two years the moon comes directly between the Earth and the Sun. Its shadow falls on Earth, and the moon blocks our view of the Sun. A solar eclipse continues for about five to seven minutes.
(One should never look directly at the solar eclipse. The Sun’s rays can harm the eyes) 
The following diagram will explain.

2)Lunar eclipse (Luna = moon in Latin) – A lunar eclipse happens about every 6 months. It happens when the Earth comes between the Sun and the Moon, and the earth’s shadow falls on the moon. The moon becomes dark. It is interesting to see the shadow of the Earth gradually moving over the moon, completely covering it and then gradually moving away. Sometimes the Sunlight filtering through our atmosphere turns the eclipsed moon red. Lunar eclipses can last for about 3 hours.

In ancient times Greek scientists concluded that Earth was round by observing these eclipses. During a lunar eclipse the Earth’s shadow on the moon looked circular.