Today, IQ Weather’s science blog discusses the miracle of water.
Water is something we use every day. We drink it, wash things in it, bathe in it, swim in it, and all the while probably don’t think about how important it is to life on earth!
Water can exist in three different forms at the same time; gas, solid, and liquid. The point at where all three can exist is called the “triple point”. And water’s triple point temperature falls within a range that makes our planet’s temperature livable. If it did not, earth would be a very different place!
Water stores and releases heat as it changes from one form to another. When water is boiled it must absorb enough heat for the water molecules to turn to a vapor. When that vapor cools, it releases the heat that is absorbed back into the air. And when water freezes, it releases the heat that it took to keep it in liquid form. And when ice is melted, it absorbs heat to return to liquid form. In these ways, water helps to transfer heat from one place to another.
Water absorbs heat from the sun and delays its return to outer space. That is a simple explanation of the so called “greenhouse effect” that keeps our planet’s temperature warm enough that we can live here. Watch This Fun Greenhouse Effect Explainer
In fact, water vapor accounts for most of the greenhouse effect on earth. When water absorbs heat, the water vapor becomes warmer than the surrounding air and rises. The heat that is absorbed rises high into the sky and is then released back into outer space. So, water helps to both heat and cool our planet. It is earth’s thermostat.
Clouds are a combination of water vapor, water droplets, and ice droplets. As one form of water changes to another, there is constant heat exchange taking place. Clouds may look like peaceful cotton balls in the sky, but they are actually working hard to move heat around and make precipitation possible.
When the cooling inside a cloud is stronger than the heating, precipitation takes place, as colder air cannot hold on to as much moisture as warm air.
When the warming is stronger than the cooling, the reverse happens, and eventually the cloud turns completely to water vapor and disappears.
Once water turns to ice, it takes 80 times more heat to melt it, than it does to raise the same amount of water 1°. Ice is quite difficult to melt. Think about it. Ice is at a temperature around or slightly below 32°F. Put ice in a cup and sit it in a room where the air temperature is 72°, and that ice will take a long time to completely melt! And at the same time, the ice-cooled cup causes moisture from the air to cool and condense on the outer surfaces of the cup!
Water seems like a very simple thing. But it is a very complex substance, and without it…we would not be able to live on this planet!
IQ Weather's homeschool science course extra study blog. How water makes life on earth possible Home science made easy.