Water comes in a variety of forms. First it is commonly known as a liquid, secondly as a solid in the form of ice and thirdly as a gas- steam. But, besides the common forms that water takes, it also has amazing properties as well. These properties are usually referred to as anomalous properties. Some of these anomalous properties include; varying volume at different temperatures and surface tension.
Water Volume at Different Temperatures
Did you ever wonder why pipes carrying water burst when they freeze or why ice floats in a river instead of sinking? It's simple, it's due to the fact that water volume varies depending on temperature. For instance, water increases in volume by about 9% at the freezing point. As the water molecules become even colder- they continue to expand. This is why water in the pipes can cause them to burst, as well as why ice floats over liquid water. On the other end of the spectrum, water molecules should boil at around 90 degrees Celsius, however due to the hydrogen bonds in the molecule, water boils at a higher temperature- 100 degrees Celsius to be exact.
Surface tension is another anomalous property of water. It can be exhibited when an insect simply strides on top of a pond or pool. Water can be a very cohesive and elastic substance. This is due to the fact that water molecules are always attracted to other water molecules adjacent to it. However, it should be noted that surface tension is only available on the surface- the reason why is that water underneath the surface of the pool or pond has zero charge. Zero charge means no net force on the molecule, but the water on the surface operates differently with forces only sideways and downward. This is what creates a stretched membrane effect and surface tension.
Pure water is actually not that pure; in reality it is almost impossible to create pure water with only H2O molecules. In all cases, pure water usually means that it is distilled or de-ionized, but there are still plenty of gases and sometimes even silica dissolved within the molecules.
Unlike pure water, our drinking water is usually laden with many different substances including sentiments such as calcium, magnesium, iron and even atmospheric gases. It should be noted that drinking water can be charged either positively or negatively, however these ions are usually balanced by the negative ions carbonate / bicarbonate, and occasionally some chloride and sulfate.
Since water can easily dissolve most substances, if you live in an area where the groundwater comes into contact with toxic materials, this can affect your water to some degree. The EPA (Environmental Protection Agency) has set limits on the amount of contaminants allowed in drinking water and local municipalities test the drinking water on a regular basis.
If you think that the only way to avoid contamination of potentially harmful substances is to drink water that comes directly from rain or snow- you should know that even these forms of water can include contaminates, mainly due particles of dust coming into contact with the water in the atmosphere.