how to make a slime farm

In order to make a slime farm you have to have at least 4 diamond pickaxe and 25 TNT (optional). You have to dig all the way down to bedrock. Then make a 30 by 45 area. Don't put to much lights, you can put enough where mobs wont spawn. As you can see slime's are in the slime farm they get bigger if left alone for a few minecraft days and they only spawn in easy, normal, and difficult never on peaceful. The reason for killing slime's is to make sticky pistons. You can only collect there slime balls by killing them with your bare hand.