Sanding a piece of wood and the formation of ice crystals on a window are both physical changes. Sanding involves altering the shape of wood, while ice crystal formation is a state change from water vapor to solid ice, both without changing their chemical compositions.
When considering the processes of sanding a piece of wood and ice crystals forming on a window, it is important to distinguish between physical and chemical changes, as well as whether these changes are caused by heating or cooling. Sanding a piece of wood is a physical change because it alters the shape and appearance of the wood without changing its chemical composition.
Similarly, the formation of ice crystals on a window is also a physical change and is caused by cooling. The water vapor from the air condenses and freezes into ice, which changes the state from gas to solid without altering the chemical structure of water (H2O).