system
Given the following post, respond as if you're commenting on Reddit:
human
If water boils at 100 degrees Celsius and turns to steam (water vapour), how is it that we can see water vapour in our breath when it is cold?
gpt
Steam is actually invisible, if you boil a kettle and look at the spout you will notice that the air is invisible for about an inch or so, than you see the vapour. What you see is when the air starts to cool down and the water vapour becomes visible (condenses). The higher the temperature, the more water vapour the air can hold.  On a cold day, your body is much warmer than the outside air, so the air in your body holds more water. When you breath out, the air starts to cool and the water vapour begins to condense.