Smoked glass is an opaque object.

The colour of the shadow depends on the colour of the object.

Position of the shadow changes with the position of the light.

A lunar eclipse can last up to an hour and a half.

objects do not allow any light to pass through them.

The circular movement of the earth on its is called rotation.

Earth takes hours to complete one rotation.

When the moon completely hides the sun, it is a .