We all know how important water is to life as we know it. Here in Southern California, our persistent drought has made us especially appreciate how precious this substance is.
What I didn’t realize until I came across the following information in some casual reading is how unusual water is. Its chemistry doesn’t behave the same as most of the other 15 million molecules that chemists have identified. And because it doesn’t, water is able to perform its almost miraculous role as the focal point of life on earth. Here are some amazing facts about water that cause scientists to marvel.
Facts About Water
- Even those of us who struggled with high school chemistry know that the chemical formula for water is H2O. It’s made up of two hydrogen atoms and one of oxygen. What’s really significant is how those atoms are arranged. Instead of the hydrogen atoms being spread equidistant from each other in a straight-across 180° configuration, they exist at a 104.5° angle while bonded to the oxygen atom. When sketched, the three atoms of water resemble the silhouette of Mickey Mouse. The significance of this is that this allows the oxygen side of the molecule to be negatively charged while the hydrogen side is positive. Because opposites attract, this makes water molecules sticky. (Actually, for reasons I can’t begin to comprehend, chemists say that the expected H-O-H bond angle should be 109.5°. So it is really that miniscule 5° less of separation that gives water so many wondrous properties.)
- Among those properties are unusual degrees of cohesion and adhesion. Cohesion refers to the fact that water sticks to itself easily while adhesion means it sticks to other things as well. Water’s adhesive property is stronger than its cohesiveness, which results in water spreading out on a surface rather than sticking together in a ball.
- The shape of its chemical bonds also gives water a high surface tension, because each water molecule is attracted strongly to its neighbors. This is why you see water elongate as it drips from a faucet.
- Water has been called the “universal solvent” because so many substances dissolve in it, including salts, sugars, acids, alkalies and even some gases, such as carbon dioxide, which gives us carbonated beverages.
- One of the weirdest yet most important properties of water is that it is one of the few substances less dense as a solid than a liquid. That’s why ice floats. If it didn’t bodies of water would freeze from the bottom up, making it impossible for fish and other aquatic creatures to survive.
- Water has a very high specific heat capacity, which means it takes a lot of heat to raise its temperature by a little. This plays a huge role in moderating our climate. You may have noticed that areas by a large body of water tend to be cooler in summer and warmer in winter than inland areas.
- Water constitutes more than 60% of all plants and animals. About 71% of the Earth is covered by water but only 2.5% is from fresh water, most of it in the form of ice and groundwater. Only 0.3% of the Earth’s water is contained in lakes, rivers and the atmosphere.
- Water is one of the few substances that exist naturally on Earth in all three phases – as a solid, liquid and gas.
- Water is tasteless and odorless. What you can taste and smell come from minerals dissolved in water.
- Whereas most substances are referred to by their chemical name, we call it water rather than dihydrogen monoxide, although that is an accurate if rather alarming description. Hoaxsters have been known to distribute petitions asking to ban dihydrogen monoxide from our environment and a lot of gullible people sign them.
I don’t know about you, but all of this is making me thirsty!