Solids:
* At rest: In solids, particles are tightly packed and vibrate in fixed positions.
* Heating: When heated, the particles gain energy and vibrate more vigorously. This increased vibration causes the particles to push further apart, leading to a slight expansion of the solid.
* Melting: If enough energy is added, the vibrations become so intense that the particles break free from their fixed positions, transitioning into a liquid state.
Liquids:
* Free movement: In liquids, particles are closer together than in gases but have more freedom of movement. They can slide past each other, giving liquids their ability to flow.
* Heating: When heated, liquid particles gain energy and move faster. This increased motion makes the particles more likely to break free from the surface, leading to evaporation.
* Boiling: If enough energy is added, the particles gain enough energy to overcome the attractive forces between them and escape into the gaseous state. This is known as boiling.
Gases:
* High energy: In gases, particles are far apart and move at high speeds. They collide with each other and the walls of their container, exerting pressure.
* Heating: When heated, gas particles gain energy and move even faster. This results in increased collisions and therefore increased pressure.
* Expansion: Since gas particles are already far apart, heating causes a significant expansion in volume.
In summary:
* Heating increases the kinetic energy of particles. This means they move faster and vibrate more vigorously.
* The changes in particle motion due to heating lead to changes in the state of matter: Solids melt into liquids, liquids evaporate or boil into gases.
* The amount of energy needed to cause these changes varies depending on the substance and its initial state.
It's important to remember that the particle theory is a model, and it provides a simplified explanation of what's happening at the atomic level. While it accurately describes the general trends, the actual behavior of particles is much more complex.
