The chemical structure of water is the same whether it is a solid (ice), liquid, or gas (steam). Think about ice melting into water, and then water being heated up and turning into steam.
A piece of metal may be heated in a fire until it glows, but the metal is the same material before heating and after cooling. Similarly, when a material changes phase, it only changes physically the substance is still the same. The wood itself has not changed during sanding to become a new material, though-only the texture of the surface changed. If you rub that block of wood with sandpaper to smooth the surface, it will no longer feel rough. For instance, a block of wood may feel rough when you run your finger across it. A change in the texture of a substance is a change in the way it feels. Examples of some physical changes are texture, shape, temperature, and a change in the state of matter. What Is a Physical Change? In a physical change, the material involved is structurally the same before and after the change. Chemical changes, on the other hand, are not reversible: A log burned in a fire turns to ashes, but the ashes cannot be changed back into a log. For example, an ice cube can melt into liquid water, and then the liquid water can be refrozen into an ice cube. Physical changes in matter are often reversible. Matter is capable of undergoing changes, which are classified as either physical or chemical.
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