The amazing liquid we call water

Water is truly an amazing substance.

We take water for granted since it is plentiful and well-managed. However, go without water for about three days and you won't be thinking of anything else. You will become severely dehydrated and possibly even die.

It's been said that a human body is 80 percent water. That's because the living cells that make up a human body are mostly filled with water. Think of a cell as a water balloon. The skin of the "balloon" is essentially fat; water fills the balloon to the right size.

That water supports all of the different cell functions. It's like the water in a cake mix. Once you add water, the cake mix becomes a soupy, thick paste. A cell without water is a solid mass that can't function. But once enough water is added, things can start to move in the water, and the cell can function.

Water has other properties that are also important for life. The air we breathe is a gas made up of about 80 percent nitrogen and 20 percent oxygen, along with smaller amounts of a few other things, such as carbon dioxide and water.

That air is made of of atoms, which themselves consist of protons, neutrons and electrons. The total number of protons in an atom determines the atom type, or element. The total number of neutrons and protons determines how much an atom weighs. A molecule is created whenever two or more atoms fuse together.

Water is a molecule composed of two hydrogen atoms and one oxygen atom. Each hydrogen atom has one proton, and no neutrons. Each oxygen atom has eight protons and eight neutrons. A hydrogen atom weighs one atomic mass unit (AMU) and an oxygen atom weighs 16 AMUs. By the way, the atomic symbol for hydrogen is H, and for oxygen it is O. Two H atoms and one O atom give the familiar H2O symbol for water.

But back to the air we breathe. Nitrogen in the air contains two nitrogen atoms in one N2 molecule. Nitrogen has seven protons and neutrons, weighing 14 AMUs. An N2 molecule weighs 28 AMUs and is a gas. Oxygen, or O2 weighs 32 AMUs, and is also a gas. Carbon dioxide (CO2) weighs 44 AMUs and is a gas. Chlorine gas (Cl2) weighs 71 AMUs. But water, which weighs 18 AMUs, is a liquid. It is one of the lightest molecules on earth.

So why is water a liquid? Shouldn't water be a gas if it so light?

Fortunately for us, water has special properties that keep it a liquid. You can think of a water molecule as a tiny magnet. If you stack several metal magnets together, you know that it takes more effort to break them apart than a stack of regular metal pieces. Water molecules tend to stick to each other like a stack of magnets does because of their shape and electronic properties. This behavior helps to keep water a liquid at higher temperatures. Most gases like N2, O2, CO2 and Cl2 are not tiny magnets, so they don't stick together.

But what if water did behave like all those other gases? What if water was a gas at 50 degrees Fahrenheit, a typical fall day in Sisters? It is likely that the oceans would not exist. The water in the oceans would evaporate first at the equator, where it is warmest, and the water in the polar regions of the earth would drain to the equator, eventually evaporating into the atmosphere. A lot of life forms on earth would be in really big trouble.

But we can thank water for behaving as an outcast, and making life easier.

Water is an outcast in another way as well. Water turns from a liquid into a solid, or freezes, at 32 degrees Fahrenheit. When a candle burns, the solid wax in the candle turns into a liquid and then burns. But have you noticed what happens to the liquid wax when the candle flame goes out? It actually shrinks as it cools down and becomes a solid. This is true for almost every substance on earth. The solid form occupies less space than the liquid form.

A solid piece of wax dropped in a bathtub full of liquid wax would sink to the bottom. Ice is different. As we all know, ice floats on water. Unlike almost everything else, water takes up more space when it freezes. Water is again an outcast.

If water conformed, and did shrink when it froze, things would be a lot different. When a lake began to freeze, starting at the lake surface where it is coldest, the ice would immediately sink, and the lake would literally freeze from the bottom up. The same thing would happen to the oceans, rivers and all other bodies of water. This would have a serious and negative effect on almost all living things on the planet.

But, thankfully, this isn't the case, and we can all enjoy our cold drinks without worrying about the ice sinking to the bottom of the glass. So the next time it rains on your parade, be thankful!

Matt Wessel has had a long career in the science and technology fields. He is a Sisters resident.