- Changing phase. This refers to the change of a substance from one phase to another, such as from a solid to a liquid, or from a gas to a liquid. This is a physical change, and does not involve a change in the chemical composition of the substance.

- Undergoing a chemical reaction. This is a process that involves the chemical bonding of atoms and/or molecules, resulting in the formation of a new substance or substances with different properties from the original reactants. This is a chemical change, and involves a change in the chemical composition of the substance.

- Being subjected to physical forces. This can include forces such as pressure, temperature, or radiation, which can cause particles to change their size, shape, or properties. This is a physical change, and does not involve a change in the chemical composition of the substance.

- Interacting with other particles. This can involve particles colliding with each other, or interacting through electromagnetic forces, such as the exchange of electrons or photons. This can cause particles to change their velocity, energy, or state of matter. This is a physical change, and does not involve a change in the chemical composition of the substance.