Water, that simple substance that is everywhere you look. It’s underground and it’s in the clouds. It flows from the tap and sold on the streets. Where ever you get yours from, everyone agrees that water is vital to life. It is so vital that when scientists are looking for aliens on other planets, the first thing they look for is evidence of water. Since water is so important, you would think that scientists know everything there is to know about water; well not exactly. You see, water does some pretty weird things that scientists still do not understand
Water does not behave like other liquids
If all liquids were students in a class, water will be that kuborlor (truant) who never turns up or obeys the rules. You may have been taught in science glass that gases take up more space than liquids and liquids take up more space than solids.
Basically when liquids freeze, their molecules squeeze together, take up less space and turn into solids. This applies to all liquids, except water which decides to expand and take up more space when it freezes to become ice. This is why bottles of water crack or break when you leave them in the freezer for too long and pure water sachets are not filled completely so that there is some space for the ice to expand into.
Hot water freezes faster than cool water
Quick question, if you put a glass of hot water and a glass of tap water in the freezer, which one will turn into ice first? If you said tap water, usually you will be right, but this time you may just be wrong. You see sometimes hot water freezes faster than normal water; it is a little trick called the Mpemba Effect that nobody really understands.
Some have said things like how hot the water is, how humid the environment is, how pure the water is and even the shape of the container can cause this Mpemba Effect. It sounds like a lot of guessing going on.
Why is ice slippery?
Have you ever tried to pick up an ice cube with your hands? Very slippery isn’t it. In colder countries, after it snows the ground also becomes very slippery and everyone is careful when walking or driving to avoid accidents.
So why is ice so slippery? If you are thinking it is because there is less friction, then the answer is ‘Yes’. But why is there less friction? If you are thinking it is because the ice is smooth, then the answer is ‘No’. You see, even when the surface looks rough, ice is slippery and no matter how much you polish or smooth over a piece of furniture it will never be as slippery as ice.
Where does this all leave us……
Water covers 70% of the Earth’s surface and without it we will all die. But there are still some questions left to be answered about this source of life we all depend on. Think about that the next time you rip open a sachet of pure water and maybe you will one day be the scientist who solves the big mysteries about water.
Fun Fact: The water you drink has a lot of added minerals and is not really pure. Water that contains only 100% water molecules is called distilled water and you can perform some nifty experiments with distilled water.