Editing Phase Of Matter - Physical Change

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Since phase (or sometimes called States) of matter you still have the same substance, the particle (usually a grouping of atoms/ions) are acting as one particle. So there is no new grouping (new substance) and the energy is used or given off relate to how the group are dealing with each other. All of that makes phase change a physical phenomena. 
 
There are actually 4 phase of matter (solid, liquid, gas and plasma) with a 5th being liquid crystal (look at display on your watch). We will not deal with plasma or liquid crystal but will look at solid liquid and gas.

Gas - base units or particles have obtained enough energy to overcome their Intermolecular Force (IMF), the force/energy that keeps particles near each other. So the particles do not interact with each other (a lie that will be explained later in gas chapter) which explains their properties: 
*Occupies all volumes (i.e. take shape of any container). 
*Compressible - meaning adding outside pressure will change volume of gas (since they have no IMF, can go anywhere so has a lot of empty space between particles

Condensed phases are liquid or solid phase. The energy of the particles is not great enough to overcome their IMF so there is IMF between particles. The difference between liquid and solids is amount of energy (the IMF is same since the substance is same, will learn more later about IMF).

Liquid - base units or particles do not have enough energy to overcome their IMF but do have enough energy to move in 3-D space. So they can "move" but still are "tied together" meaning IMF does not allow particles to go anywhere. This explains their properties: 
*Occupies shape of a container to its own level
*Not compressible - since IMF exist, particles are close enough together that there is not sufficient amount of empty space to measure reduction in volume with pressure change (so we say there is no volume change with pressure change Tthis is a lie and we will deal with it later).

Solid- If energy is removed enough, the IMF will be so great that the particles can not move in 3-D space but will vibrate in space (since all particles are moving and have energy). This explains their properties: 
*Occupies its own shape (since particles do not have enough energy to move in 3-D space)
*Not compressible - see explanation for liquid above
 
So to paraphrase, going from solid then liquid then gas is simply a matter of different amounts of energy the particles have and the particles staying the same. Therefore, it is a physical change (called process).

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