Water breaks the rules and that’s why we’re alive!

It’s colourless, odourless and virtually tasteless. It’s hard to imagine a more bland, ordinary substance than water. To a chemist, however, water is an extraordinary chemical. It does strange and unexpected things, without which Earth could not sustain any living creatures.

Chemistry’s Mickey Mouse

, Water s design is deceitfully simple. Each molecule is made of three atoms: two hydrogens and one oxygen (hence the well-known formula, H2O). The two hydrogen atoms are attached on either side of the oxygen – like Mickey Mouse's ears and head! The oxygen atom is slightly negative and the hydrogens are slightly positive. The positive hydrogens on one molecule are attracted to the negative oxygen of a neighbouring water molecule. This pulls the two neighbouring molecules together with a force that is called a ,,hydrogen bond,,. These hydrogen bonds are responsible for most of water's special properties.

Water can dissolve just about anything

Water is brilliant at dissolving things – so good at it that it's called the ,,universal solvent,,. This property is due to the positive and negative

charges on each molecule that attract other chemicals. Water's dissolving superpower is necessary for any living creature to exist.

In plants, plant sap transports minerals, hormones and sugars. In humans, water makes up 92% of the blood plasma and transports hormones, minerals, sugars, fats and proteins, as well as waste products. As the blood circulates around the body, it delivers the nutrients and hormones to the cells that need them. The waste products go to the kidneys where they

are dissolved in water to make urine.

Ice floats on water

As most liquids cool and turn into a solid, their particles move closer together and they become denser. Water breaks this rule. As water approaches freezing point (0°C), neighbouring water molecules are attracted to each other because of the opposite charges between the hydrogens and oxygens. These forces push the molecules slightly further apart, making ice less dense than liquid water. This makes ice float on water instead of sinking. If ice behaved like other solids and became denser than its liquid it would sink to the bottom of lakes, ponds, rivers and the sea. The water would then freeze from the bottom up. A floating ice layer shields the water below it from the cold above, preventing the water from freezing completely so that the creatures who live below can survive.

Water exists in all three phases

Water is the only substance that exists in all three phases of matter (solid, liquid and gas) at temperatures found naturally on Earth. All three of these phases are necessary to keep things on Earth running shipshape. The ice caps at the poles regulate the climate by reflecting sunlight and cool the oceans, creating ocean currents. Liquid water is found in plants, animals and humans. It transports substances and facilitates all kinds of chemical processes. Water is a liquid at room temperature, making it easily available for drinking (imagine if water was ice or water vapour at room temperature – you would not be able to drink it)! Water as a gas (water vapour) is a vital part of the water cycle. Without it, clouds could never form and there would be no rain.

If you leave a bucket of water in the sun for a few hours on a scorching summer,s day, it will warm up, but you,ll still be able to put your hand in it. On

the other hand, a car parked in full sun becomes so hot you can fry an egg on it. Certain substances, like metals, have a low heat capacity – meaning that you don,t need to add a lot of heat energy to increase their temperature. On the other hand, water has an astonishingly high heat capacity, so it takes

a lot of heat energy to raise water,s temperature. The vast amounts of water on Earth stabilise Earth,s temperature, helping it to sustain life. When it,s hot, the oceans absorb the heat without warming up too much. When it,s cold, the oceans can lose a lot of heat

without cooling down too much.

Water can handle the heat

Water has a very

high surface tension, that’s why

some insects like water striders can

walk on water.

ICE Hydrogen bonds are stable Hydrogen bond LIQUID WATER Hydrogen bonds constantly break and reform.

If you were to chop anything on Earth into its smallest possible pieces, you would end up with atoms. Atoms are the tiny building blocks that make up all matter.

Gas Liquid Solid Snowflakes are a special type of ice. They always form six-sided figures.