Explain how day and night is formed?

The Earth carries two kind of motions...it revolves around the sun and rotates at its own axis at the same time. Day and night occurs because of the rotation of Earth.The sun shines all the time but only half of the earth faces the sun at a time.The portion which faces have day and other half has night. When the earth rotates the part which has day has night and the night has day.

The earth rotates in relation to the sun once every 24 hours. When the sun" rises " it is actually the earth turning towards it. And so as the sun appears to move up and  across the sky and then" set" it is the earth turning in its 24 hr cycle that causes this effect and so after the sun has "set" it means we on our half or hemisphere are turned from the sun and towards dark space and we get night until it is "sunrise" again. So one half of the earth is in sunlight all the time while the other half is in darkness. Ou can try this out with a lamp for the sun and you turning away and toward sit  to simulate the earth.

It is due to the rotation of the Earth about its axis. The Earth has a period of 24 hours when it completes a complete turn about its rotational axis.  While rotating only one half face of the Earth faces the sun which we call daytime and the other half is dark i.e. Night.

As the Earth rotates, the part furthest from the Sun is in shadow.

The part which faces the sun have day and the other part will have night.

Because of the movement of earth

Because of the Earths rotation in respect to the sun.