Static Electricity Box

Physics:	Electricity
Grade Range:	Middle School, High School
Format:	Hands-on

The static electricity box is a small box covered in plastic and contains aluminum foil balls. This quirky box displays some surprising and fun properties of static electricity up close that students can play with.

Materials

• Static electricity box:
  • Aluminum foil
  • 1 cm diameter Styrofoam balls, wrapped with aluminum foil
  • Small clear plastic dome with base (Such as a cookie platter tray)
  • Small cardboard boxes, cardboard strips, or similar
• Piece of paper towel, cloth, or fur

Safety Precautions

• Please see the Demonstration Safety Page for General Safety Precautions

Demonstration

Preparation

Assemble the Static Electricity Box

1. Rinse out the plastic platter tray and dry. Stack the small cardboard boxes, strips, or similar until they nearly touch the lid of the tray when inside. Tape them together.
2. Line the top cardboard box (or cover the top of the stack) with an aluminum foil sheet. Cut two additional sheets to then fold and stack on top, pressing them in and leaving the edge elevated.
3. Place some of the Aluminum-wrapped styrofoam balls inside the aluminum lined box. Close the lid on top, ensuring it is a snug but sturdy fit.

Presentation

Style A:

1. Rub the plastic lid with your cloth (a circular motion work best). Some of the balls inside the box should begin bouncing around and floating. It is also possible to get a couple to stick against the bottom of the lid.
2. Put your finger tip close to touching the outside of the lid, above where the Styrofoam ball is sticking. The ball will move around!

Style B:

1. Rub the plastic lid with your cloth (A circular motion works best), then place the extra Styrofoam balls wrapped with aluminum foil on top. They will shift around a bit, then stick into place.
2. Once the Styrofoam balls are in place, bring your finger tip close to one of the balls (or just barely touching it) and the ball should roll and jump around the top of the lid!

Why This Works

Short Explanation

In static electricity, charges (+ and -) are separated from one another. Due to the properties of the materials these charges are separated onto, some of these charges are not able to disperse, and are "stuck in place" (i.e. if the surface is a nonconductor). One property of charges is that opposite charges attract each other and like charges repel each other. In the case of this demonstration, rubbing cloth on the plastic (made out of polycarbonate, a nonconductor) makes parts of the blast shield - charged. The aluminum foil-wrapped Styrofoam balls are attracted to the charged surface, and will jump to it!

When the balls are on the blast shield, students can see that they move if they try to poke them. This is because, when they touch the plastic, they remove the - charge on the surface. The balls will then fall back down, or they will slide around the blast shield trying to find another spot that is charged.

Tips and Tricks

• Try to make the blast shield as flat across the top of the box as possible
• This demonstration goes well with Van de Graaff generator and other static electricity demonstrations