Which type of phase change does the term 'fusion' refer to?

Fusion refers to the phase change from a solid to a liquid. This process occurs when a solid absorbs heat energy, which increases the temperature of the particles within the solid. As the temperature rises, the particles gain enough energy to overcome the forces binding them in the solid structure, allowing them to move more freely and transition into the liquid state.

An example of fusion is the melting of ice into water. When ice is heated, it absorbs energy and eventually reaches its melting point, at which point it transforms into liquid water. This concept is crucial in understanding changes in states of matter and how temperature and energy affect these transformations.