Editing Static Electricity Box (section)

== Why This Works ==

'''''Static electricity''''' is when charges ('''+''' and '''-''') are separated from one another. This separation is often due to materials which are '''''insulators''''', meaning materials that are good at preventing charges from moving, rub against each other. While this happens, the charges are separated onto the surfaces, and are "stuck in place" (i.e. the charges cannot be dispersed). A major property of charges is that opposite charges attract each other, and like charges repel each other. That is, '''-''' attracts '''+''', but '''-''' repels '''-'''. However, anything that has a neutral charge will be attracted to '''''either - or +'''''.

In this demonstration, rubbing cloth on the plastic, an insulator, makes the lid '''-''' charged. The aluminum foil-wrapped Styrofoam balls are attracted to the charged surface, and will jump to it! The styrofoam balls are neutral charge, and are attracted to the '''-''' charge on the surface. The aluminum foil is a '''''conductor''''', or a material that is good at letting charges move through it, so the - charge of the surface never reaches the styrofoam ball. Instead, the charge stays on the aluminum surrounding it!

When you try to poke the balls, you can see that they move away. This is because, when your hand touches the plastic, it removes the '''-''' charge on the surface. With the charge gone, there is nothing attracting the balls to that spot anymore, so the balls will either fall back down, or slide around the lid to another spot that is charged.