# Physics Van - Human Charges

## Electricity

### Materials:

• Two red hats
• One blue hat
• Two Physics Van members

### Key Points:

• Electricity is made up of two opposite kinds of charges (officially called positive and negative).
• It doesn’t matter what you call them, the important part is that they are opposite. We'll can call them Red and Blue since we have hats of these colors.
• Like charges repel. Opposite charges attract.

### Warnings:

• Older audiences already know about charges. You may want to eliminate this demo for audiences that don't have kids younger than 5th grade or so.
• Make sure the "charges" agree on what they're going to do when they meet, so they don't collide or get confused and look dumb.

### Things to talk about:

• This is the first electricity demo. Tell the audience we’re switching gears and we’re going to talk about how electricity works.
• Ask them for examples of things that use electricity.
• Ask if anyone knows what electricity is made of.
• Electricity is made up of tiny little things that we call charges.
• There are two different kinds of charges. Most scientists call them Positive and Negative, but the names don't really matter. We can call them Red and Blue.
• The most important thing to remember about charges is that charges that are the same want to get as far away from each other as they can; and charges that are different want to get as close together as they can.
• Get two Van volunteers and tell the kids that you're going to make them both "Red" charges by putting the red hats on them.
• Once the charges are activated, they should proceed to run in opposite directions and hide from each other.
• As you walk over to one charge, tell the audience that you’re going to switch one of the Red charges so they’re a Blue charge, and see what happens.
• Change the red hat for blue, and as the charges run together, restate that opposite charges want to be close together, and like charges try to be far apart.
• Break up the charges’ dancing around before it makes everyone sick.