# Science for Kids/Physics (mechanics)

Question
Newton's third law states that for every action there is an equal and opposite reaction force . Considering this any thing which moves in the earth's atmosphere should experience an opposing force from the atmosphere and therefore it should not move . But this is not the case . My question is - Why the body moves and if the reaction force comes after some time of doing action ?

The body moves forward, and the air moves backwards.  You can see the body moving, but you don't see the air moving backwards.  Likewise, when you walk south, you push the Earth a little bit north.  But it's so heavy and massive that you don't notice it.

The reaction happens at exactly the same time as the action.

Science for Kids

Volunteer

#### Sue Kayton

##### Expertise

I can answer almost any student science question! I especially like ones involving silkworms, spacecraft and computers.

##### Experience

MIT graduate. Have worked as an engineer and taught science for 28 years.