* Physical Changes: Alter the form or appearance of a substance but not its chemical composition.

* Chemical Changes: Result in the formation of new substances with different chemical properties.

When you freeze juice, the water molecules slow down and arrange themselves into a solid structure (ice). When you melt it, the molecules gain energy and move more freely, returning to a liquid state. When you refreeze it, the process repeats.

Key Point: Throughout this process, the juice itself remains the same. It's still the same mixture of sugars, acids, and water. You haven't created any new substances.