So this is a fancy shmancy Leyden Jar. It's basically a jar filled with salt water with aluminum foil around the outside of the jar. In essence, this is a capacitor, so when you charge the inside (negative) the grounded outside would then become charged as well with the opposite charge of equal value (positive in this case). When you then touch the wire thingy to the nail on top you would be neutralizing the two sides causing a spark between the wire and the nail.

Step 1: Step 1: Get Your Materials.

You're going to need a glass jar, four pieces of tape, much salt, an a wire.

You also need a jar lid that fits the jar you have with a nail nailed through it. We would have showed a step for this but by the time we started making this Instructable we had already had a jar lid with a nail nailed through it, so we're sorry we're lazy but we don't want to do that again just for the sake of pictures. Also note that we hot glued the nail into the hole too because we didn't want to be electrocuted.

Step 2: Step 2: Fill Your Jar With Water Around 3/4ths Full.

Find a sink and fill your jar.

Step 3: Step 3: Add Salt

Add copious amounts of salt to your water. Like a lot of salt, but not enough to have more salt than water. just enough for the water to be kind of cloudy.

Step 4: Step 4: Screw on the Lid

so nothing spills, also try to make sure that your nail can reach the salt water.

Step 5: Step 5: Wrap a Piece of Aluminum Foil

wrap and tape the aluminum foil around the jar.

Step 6: Step 6: Tape the Wire

Tape the wire on the aluminum foil somewhere kind of like the picture. make sure the tip of the wire can touch the nail and the other end can touch the aluminum.

Step 7: Step 7: Test It

So you should charge the inside part of the Leyden Jar somehow. Our method was rubbing wool on a plastic rod and then rubbing the charged rod onto the nail. But thats just us. Our own results were a little iffy, we managed to get it to spark a couple times, but not entirely consistently, We'd suggest trying to get it to spark in a dark room so that you can see the spark when it happens.