A phase change is the process in which a substance changes from one physical state to another, such as from a solid to a liquid or a gas.
A phase change is caused by a change in temperature or pressure. When a substance reaches a specific temperature or pressure, its molecules will rearrange themselves and change from one state to another.
The three main types of phase changes are melting, freezing, and boiling. Melting is the process of changing from a solid to a liquid, freezing is the process of changing from a liquid to a solid, and boiling is the process of changing from a liquid to a gas.
No, a substance cannot skip a phase change. It must go through each phase change in order for it to change from one state to another. For example, water cannot go from a solid directly to a gas without first melting into a liquid.
Energy is involved in a phase change because it is necessary to break or form bonds between molecules in order for the substance to change states. For example, energy is needed to break the bonds between molecules in a solid to change it into a liquid.