Verified answer

A plow slices through the soil and turns it over to loosen the soil for crops. It's a curved blade, having a point at the end to dig in and the ear turns over the sliced earth. See this site:

http://en.wikipedia.org/wiki/Plowshare

Ideally, soil should consist of 1/8 water and another 1/8 air with a lot of nutrients. These form deeper in the soil where ants, worms and microorganisms break down organic matter. So there are little nutrients on top where plants need them, the soil is constantly compacted by heavy machinery.

It's the plough's job to correct these problems. Turning the soil upside down kills off weeds, repeates the nutrient cycle, breaks up the soil into smaller pieces, filling it with more air filling and allowing it to hold more water.

The plough is nothing more than a frame with a knife that cuts a vertical line in the soil, a chisel and share set at the correct depth cut another line, this time horizontally under the soil. This loose "track" of soil is now free and slides along the board (the biggest piece of the plow) which plips it upside down. And that's it.

I've stuck with the basic parts, there are many more... but it's a start. The benefits and disadvantages of plowing are a never ending debate.

Look here...

http://www.youtube.com/watch?v=Emj7FLFC-Dw

you will see the plow being pulled, Notice how the blade digs into the soil and turns it over. Also there is a bucket looking thing which is a container to hold seed so the farmer can plow and seed.

Good luck!