This post was written by Kirill…
A question often asked by small children, but not often fully understood by adults is, “Where do puddles go?” Water has two ways of escaping from the puddles. One explanation found on the internet (Answers.com) is…
“The water has two ways to go after being in a puddle. One way is that it can drain down into the ground through the dirt. Sometimes puddles are on surfaces that are unable to let water through, like tarmac or pavements. That means the water has to go somewhere else. So the water in the puddle goes up into the air, by a process called evaporation. This happens because water and everything else is made up of molechules. Molechules are too small for the eye to see. The molechules of water slowly go up into the air, and over time the puddle disappears.”
Apart from the spelling of molecules, and the fact that evaporation is not explained, this is not a bad explanation. It is a scientific fact that water (or H2O) evaporates or boils at 100 degrees Celsius. Then how come the water in the puddles does not only infiltrate into the ground (if possible) but also evaporates? Well the answer is one that in my point of view needs an explanation.
Water like any other substance in the Universe is made up of atoms, when the temperature is higher than its freezing point, then the water molecules move around because of the energy transferred into them by the heat of the sun’s rays. As the molecules move around they bump into each other, the higher the temperature the faster and stronger the movement of the atoms and molecules. If a molecule at the surface of the water is hit with enough power and energy the intermolecular forces holding them together will break, making the liquid water a gas for a few seconds. If when this happens there is a breeze the molecule that has evaporated will be caught and move away, unable to rejoin the puddle. Now you might think that that’s a bit too many ‘ifs’ but when you realise that the process takes only a few seconds, and is happening 24/7, then the odds become much more reasonable.
Let me also explain a bit about why puddles are in a concave bowl. When it rains the raindrops hit the ground. After some time enough raindrops will hit a single place to ensure that there is a small bowl like shape there. As more raindrops hit this single place because they run down its sides to the lowest point because of gravity, this increases the puddle.
Questions…
- Evaporation means a liquid turning into a gas, but what word means a solid turning into a gas?
- How does the boiling point of water change with air pressure?
- If H2O is the chemical formula for water, what is the chemical formula for…
a) sulphuric acid
b) methane
c) glucose
d) potassium permanganate
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