# Physics Van - Human Atoms

## States of Matter

### Materials:

• A few Physics Van members
• Volunteers from the audience (a few more kids than Van members helping)

### Key Points:

• Each person represents an atom.
• Atoms and molecules make up everything around us, in other words, matter.
• "Molecule" may be a new word to some kids. Just say a molecule is a few atoms stuck together in a group, and it acts pretty much like an atom.
• Solids: The atoms are held together tightly (locked arms) and cannot move around much.

• Liquids: When the atoms get heated up, they don't hold onto each other as tightly (holding hands). The atoms can slosh around more freely.

• Gases: When the atoms are heated even more, they eventually let go completely and are free to move all over the place (running around unchecked).

• When the atoms are running around the room, notice that they take up much more space than when they were liquids or solids.

### Warnings:

• Make sure that Van members make up the ends of the atom line. This way you make sure the line doesn't whip around and knock people over.
• Gas phase: the kids tend to get a little rowdy. It's best to keep this part short and try to minimize the amount of bumping into each other.

### Things to talk about:

• Tell them we want to talk about "stuff". Matter is just a scientist's way of describing all the stuff around us.
• We know of three common types of matter. Ask the kids if they can name the three kinds.
• Ask for or give examples of each kind (i.e. ice, water, steam).
• Now you need to collect some volunteers.
• Explain that all matter (solids, liquids, and gases) is made up of tiny pieces called atoms and molecules.
• You could mention that if you cut stuff up into smaller and smaller pieces, the smallest piece you can get is an atom.
• Mention that some things are made up of molecules, which are just groups of atoms stuck together. Each molecule acts kind of like an atom.
• Tell them that each of the volunteers in the line is going to be an atom.
• Have the atoms link arms and hold on tightly. Tell the audience that they are now a solid, and they can't move around much, like real solids.
• Now talk about what happens when you add heat to the atoms. Have the atoms hold hands, and slosh around, like a liquid.
• Add even more heat, and explain that the atoms are now going to be a gas. Tell the atoms to let go of each other and move around. Make sure the audience notices that a gas takes up much more space than a liquid or solid.
• Thank your helpers and have them sit back down.