Final answer:
When water is heated to 100 degrees Celsius, it becomes steam through the process of evaporation. To turn it back into water, you need to cool it, this process is called condensation.
Step-by-step explanation:
When water is heated to 100 degrees Celsius, it begins to boil and transform into a gas state, known as vapor or steam. This process is called evaporation.
To get water back from steam, you need to cool it back down to a temperature below its boiling point. This process of turning steam back into water is called condensation. Condensation happens when the gas particles lose their energy and get back together forming a liquid.
For instance, when you see steam coming from a boiling pot of water and the steam hits a cold window, you'll see water droplets. That's condensed water, which was previously the steam you saw rising from the pot.
Learn more about Changes in States of Matter