Final answer:
Atoms in a solid vibrate in place, while in a liquid, they move past each other and in a gas, they move freely. PhET Interactive Simulations effectively demonstrate these phase changes by allowing users to add or remove heat and observe real-time responses in a substance's behavior.
Step-by-step explanation:
Modeling the atoms of a substance as they move through the solid, liquid, and gas states involves understanding the energy and forces between particles in each state. In a solid, atoms are in close contact, vibrating in place due to the forces between them, similar to the way springs can stretch or compress.
As heat is added, the substances enter the liquid state, where atoms or molecules are still in contact but now have enough energy to move past each other. With further heating, the substance becomes a gas, where atoms or molecules have enough energy to move freely and only occasionally collide with one another.
PhET Interactive Simulations can be an excellent tool for visualizing these changes. Through these simulations, you can add or remove heat and watch the phase change occur. Additionally, you can change the temperature or volume of a container to see real-time responses on a pressure-temperature diagram. These explorations help relate the interaction potential to the forces between molecules.