Do a selection of the activities.
Introduce/review that everything is made up of tiny tiny particles, too small to see. (An atom is 10-10m, or 10 million in a dot one mm wide.)
In a solid the particles are packed close together, that is why a solid feels hard. In a liquid they are further apart. In a gas they are far enough apart that we can move through them easily - move your hand through the air and the wind you feel on your hand is the molecules bumping into your hand.
Either ask students to point to examples of the states in the classroom, or do the states of matter scavenger hunt.
[Some students may also point out that plasma is also a state of matter, which it is. The sun contains plasma.]
Optional: book on states of matter: “Matter” First Fact book (Capstone Press)
With classroom or hallway space, act out the states of matter to model what the particles are doing in each state (maybe using water in epsom painting as an example for liquid to gas).
Demonstrate how warmer molecules move faster than cooler ones with molecules moving in warm and cold water
If doing frost, set up near the start of the lesson, as it takes some time to form.
Epsom salt painting: show epsom salts dissolving in water to show students what is in the solution that they will paint with. As the students paint and see crystals forming, describe how the water evaporates from the paper, leaving behind the epsom salts.
Look at state changes in water (including the icy frost formed on the cans, if they were set up).
Optional: as part of this activity measure the temperature of water in the different states of matter.
Dancing raisins is a simple activity on state changes and density that can be extended into interesting discussions. Raisins with gas bubbles attached are overall lighter (less dense) than the water they are in so float upwards. The bubbles pop at the surface, making the raisins overall heavier (more dense) than the water, so they sink again.
Note that dissolved carbon dioxide gas is no longer a gas, but in a "dissolved state".
Cartesian diver also demonstrates that with more air associated with an object will make it lighter (or less dense) than the water it is in. Pushing air in and out of a pipette makes it alternately float and sink.
Oobleck challenges notions of solid and liquid, as it behaves like both, depending on how it is moved.
Dry ice in water is an exciting way to show state changes of carbon dioxide and water at different temperatures.
Snacks that exploit state changes:
Popcorn and skits, or ice cream. Students can act out what is happening to the molecules as they change state to make the snack.
