Explain what happens to the particles in a substance during a physical change.

During Physical Change there would be a re-arrangements of atoms or molecules, changes of the arrangement may be change in the distance between atoms or molecules, change in the crystal form, etc 

for example: water when heated it undergoes a Physical Change and turn into vapor, this means the heat cause the distance between water molecules to increase, so it transferred from the liquid form to the gas form. 

NOTE that in Physical Change there is no change in the chemical structure and the material retains all its chemical properties, and no new compounds are produced. 

again, A physical change is any change not involving a change in the substance's chemical identity. Matter undergoes chemical change when the composition of the substances changes: one or more substances combine or break up (as in a relationship) to form new substances.Physical changes occur when objects undergo a change that does not change their chemical nature. A physical change involves a change in physical properties. Physical properties can be observed without changing the type of matter. Examples of physical properties include: texture, shape, size, color, odor, volume, mass, weight, and density. 

BUT in Chemical Change ( or Chemical Reaction ) there would be change in the chemical nature of the material undergoing a Chemical Change with the production of new compounds.