During a physical change, the particles in a substance undergo changes in their arrangement, motion, or spacing, but their fundamental nature and composition remain the same. Specifically:
- The particles do not change into different particles; the substance's identity remains unchanged
- The particles may move closer together or farther apart depending on the change in state (e.g., melting, freezing, evaporation), but no new substances are formed
- The kinetic energy of the particles changes: for example, during melting, particles gain energy, move faster, and overcome some of the forces holding them in fixed positions, allowing them to move more freely as a liquid
- The forces of attraction between particles are affected: strong in solids (particles vibrate in fixed positions), weaker in liquids (particles can move past each other), and very weak in gases (particles move freely and are widely spaced)
- The number and type of particles remain constant; only their physical arrangement and motion change
In summary, during a physical change, particles rearrange or change their motion and spacing without altering their internal structure or composition, resulting in changes in physical properties such as shape, state, or volume, but not in chemical identity
