Earth obstructs the parth of sunlight (Lunar Eclipse)

While revolving around the Earth, the Moon moves in such a way that sometimes the Earth comes in between the Sun and the Moon.  In this condition the Earth does not allow the sunlight to reach the Moon. As the Moon does not have its own light but looks shining by reflecting the light of the Sun, therefore, when the Earth obstructs the path of sunlight, then instead of looking bringht the Moon starts looking dark. It is called lunar celipse.

Lunar eclipse can be eithter complete or partial.  Complete lunar eclipse occurs when the Moon comies completely under the shadow of the Earth. Partial lunar eclipse takes place when some part of the Moon reflects the light of the Sun and rest of its portion is under the shadow of the Earth.

Activity Example

Suspended a football and a tennis ball by means of chords in front of a table lamp according to Fig. 18.5. Switch on the table lamp and observe the shadow of the football on the tennis ball.

Has the shadow of the football covered the whole tennis ball? Considering tennis ball as Moon, football as Earth and lamp as Sun, explain the lunar eclipse through this model.