The changing of water to steam is a physical change because it is still water, but only in a different state. The steam can change back into water which is a reversible change. Chemicals changes cannot change back. They are permanent.
Water turns into steam by boiling, which means the water temperature rises above the boiling point (about 100Â°C in most cases, but it depends on the air pressure). Steam turns back into water by condensing, which means the temperature drops back below the boiling point.