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Learning how boiling water turns a liquid into a gas.
Have you ever watched a pot of water on the stove and seen 'ghostly' white clouds floating up? Where does the water go when it disappears into the air?
Water is usually a liquid. You can pour it, splash it, and drink it. But water has a secret! When water gets very, very hot, it changes. It stops being a liquid and turns into a gas. We call this gas steam. Think of it like a magic trick where the water changes its shape so it can float away!
Quick Check
What is the name of the gas that water turns into when it gets very hot?
Answer
Steam
To turn water into steam, we need heat. When we put water on a stove or in a kettle, the heat makes the tiny parts of the water move faster and faster. Eventually, they move so fast they break away from the rest of the water and fly into the air. In science, we say the water reaches its boiling point. For water, this happens at or .
1. A grown-up puts cold water into a kettle. 2. The stove turns on and adds heat. 3. The water gets very hot and starts to bubble. 4. White clouds of steam shoot out of the spout!
Quick Check
What do we need to add to water to make it turn into steam?
Answer
Heat (or making it very hot)
When water turns into steam, it looks like it is disappearing. If you leave a pot of boiling water on the stove for a long time, the water level will go down. The water isn't actually gone! It has just changed into a gas and is now hiding in the air around you. This is why the air in a bathroom feels 'heavy' or wet after a hot shower.
1. It rains and leaves a small puddle on the ground. 2. The sun comes out and shines heat on the puddle. 3. The water slowly turns into invisible gas. 4. By the afternoon, the puddle is gone because the water moved into the air!
1. You take a very hot bath, creating lots of steam. 2. The steam (gas) touches the cold bathroom mirror. 3. Because the mirror is cold, the gas turns back into tiny drops of liquid water! 4. This is why the mirror looks 'foggy' after your bath.
What form of matter is steam?
What makes water turn into steam?
When water turns into steam, it disappears and is gone forever.
Review Tomorrow
Tomorrow, look at a cup of hot cocoa or tea. Can you see the steam rising? Remember that those clouds are water turning into gas!
Practice Activity
With a grown-up, put a small amount of water in a cup and leave it on a sunny windowsill. Check it every day to see if the water 'disappears' into the air!