Evaporation: from liquid into gas
When liquid iron receives more and more heat, it begins to boil and evaporate into iron gas. Iron gas cannot be photographed, because gas is invisible. The boiling point of iron is almost 3 000 degrees Celsius.
Similarly, when heat is applied to liquid water, it will begin to evaporate into an invisible gas we call water vapor. It is possible for us to see hot clouds of steam rising from the pot in which water is boiled. This steam is not water vapor, but instead consists of small droplets of liquid water. Eventually, these droplets will also evaporate into invisible water vapor.
Image on the left: When liquid iron receives enough heat, it begins to boil and eventually evaporates into iron gas. Image on the right: When heat is applied to liquid water, it begins to evaporate into invisible water vapor.
When water boils, it evaporates into gas even at the bottom of the pot. Water vapor can be seen rising through liquid water in the form of bubbles. The normal boiling point of water is 100 degrees Celsius.
If you could see things at an atomic level, you could observe, how the molecules that make up liquids cling to one another while moving. When more heat is applied to the liquid, the molecules begin to move more and more. Eventually, the molecules will detach from one another completely, bumping into each other at great speed.
Image on the left: Water vapor can be seen as bubbles rising to the top of the container. Image on the right: When heat is increased, the amount of molecular movement also increases.