Water is life. Period! It is bar none the most abundant and important commodity here on Earth. Imagine a world without no water, and life would be impossible. Here’s the question: so what makes water a key component in sustaining life on Earth, and not any other planet in our solar system and beyond? Well…, the answer lies in water itself. The chemical and molecular properties of water is what’s doing the magic. Here are five essential properties of water that allows it to support lifeforms here on Earth. Do you care for a glass of water?
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Water is a liquid, and ice is a solid, but ice floats on top of water. How weird? To understand why, a crash course about density. This is the measure of how closely molecules are packed together. The closer the molecules, the greater density, and the wider the molecules, the lesser density. What’s happening here is that, water molecules are less dense as a solid than it is as a liquid. Water molecules are closely packed together in the liquid state than the solid state, therefore ice floats on water.
What this means is that, when molecules are farther apart, there are more spaces in between them for air. So in practice, there are more air packets in the water molecules in ice than there are in liquid water. What has this to do with life here on Earth? Short answer: everything! Ice floats on top water, for instance, the ice sheets covering a lake. This serves as an insulation for the organisms below. What if ice sank to the bottom, most organisms in water would be crushed during the winter. And there will be no more ice skating.
#2. Heat Capacity
Water molecules are made up of hydrogen bonds. What this means is that, it takes a lot of energy to break them up. This is why water takes a lot of time to change from one state of matter into another. Water does not experience large temperature changes. It will take a lot of energy to heat up water and it will lose a lot of energy to cool down. This is termed as high specific heat.
Think of a lake, for example, what if the water suddenly when from 21 degrees Celsius (70 degrees Fahrenheit) to say 4 degrees Celsius (40 degrees Fahrenheit) in just a few weeks, it will disrupt weather patterns, and destroy lot of aquatic activity. Water temperature changes a slow pace, and this is what allows organisms to cope and adapt to the ecosystem before the seasons change.
This is why you’re even alive. What if water quickly changed temperature, our bodies will always go from too hot to too cold in an instant depending on what the temperature is outside. The high specific heat property of water ensures that your body’s thermostat is regulated at a constant temperature. This is essential in all living organisms, too.
Fact: water is the only compound that can transition into all the three states of matter — albeit solid, liquid, and/or gas. Pure water transitions between solid and liquid states at a temperature of 0 degrees Celsius (32 degrees Fahrenheit) at sea level, and vice versa. This temperature is known as the melting point or freezing point. As it rises, ice melts from a solid into liquid water, as it drops, water freezes into ice.
However, the boiling point of water varies depending on atmospheric pressure. At low pressure or high altitudes, the boiling point of water is lower, whereas at sea level, pure water boils at a temperature of 100 degrees Celsius (212 degrees Fahrenheit). To wrap it up, the freezing and melting points of pure water occurs at the same temperature. Meanwhile, water can be a gas at either hot or cold temperatures. This property is critical for sustaining the atmosphere.
#3. Polarity, Cohesion, And Adhesion
Water is a polar molecule. Do you remember from science class? Like duh! You don’t. What this means is that, oxygen atoms pull more strongly on electrons than hydrogen atoms do. This creates two poles on the water molecule: one with a positive charge and the other with a negative charge. And you remember that positively charged ions attract negatively charged ions, and vice versa, huh? This reaction dictates how water molecules behave and interact with other molecules.
(Fun fact: Did you know that water molecules, hydrogen and oxygen, does not generate electricity? Learn more).
#5. Solvent Abilities
The polarity of water also makes it a great dissolving solutes. This is why water is often known as the universal solvent. What happens here is that, the attraction of the negatively charged ions and the positively charged ions makes it easy for them to form new bonds. Water molecules are able to break down the bonds between molecular structure, thus in turn, dissolving them easily.
However, this can only happen with polar bonds. Non-polar bonds like lipids — fats, oils and co. — can never be broken down by water molecules. Ever tried mixing water and oil before? You know what we mean. This property is extremely essential in cellular processes.
What’s even more?
Vaporization (vapor pressure) and fusion, miscibility, condensation, and compressibility, among several other features that makes it possible for you to care for a glass of water.
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Written by: Nana Kwadwo, Wed, Mar 02, 2022.