Comprising an oxygen atom with two hydrogen atoms stuck to it, water, as mentioned, is odourless, transparent and tasteless. It also has a strong surface tension and a high boiling point in comparison to most other liquids. In its solid state (ice), it is actually less dense than in its liquid state, and it’s a good solvent, particularly for minerals – but not for fatty and oily substances (hence why we survive it!). Water is very good at storing energy and has a high heat capacity, which is why it takes a lot of heat to boil it. More curious still, is that water is amphoteric – meaning that it can act as an acid or an alkaline base because a small percentage of its molecules become hydroxide ions or hydrogen ions.
Water is actually at its most dense at four degrees!
Oh, and it also covers 71% of Earth (or “Planet Water”, as Hannah calls it), and there may be more of it in rocks than there is in our oceans!
2. Hydrogen bonds give water its wacky quality
The characteristics of water make it quite an extreme example of a liquid. The way it behaves is down to hydrogen bonds. These are created because the oxygen atom is “greedy” for electrons, as quantum physicist Professor Patricia Hunt describes it. This means that the hydrogen atoms, sticking out at either side, end up positively charged while the oxygen atom is negatively charged. The different poles of the molecules start sticking to their opposites. However, although they form a hexagonal structure, they don’t do that in a fixed way because the bonds are turning on and off all the time.
3. Water expands as it cools
Counter-intuitive but true! Most things contract as well as get colder when you take energy out because there are fewer vibrations. However, when water is cooled the hydrogen bonds become more stable and the now more fixed hexagonal molecule structures layer on top of each other, leaving a lot of space down the middle of the sheets that are forming. This is why ice sits on top of water. Water is actually at its most dense at four degrees!
