Water can exist naturally on the planet in three physical states– solid (ice), liquid (water) and gas (steam/ water vapour). Water boils i.e. turns into a vapour at 100°c and freezes i.e. turns into ice at 0°c. It is remarkable as ice is one of the few solids that are less dense than in its liquid form (water), which explains why ice floats. Water helps to buffer temperature changes in cells because it has a moderately high specific heat capacity (this means it can absorb a lot of heat before it starts to get hot). This can be seen in waters high melting and boiling points. Below is a table that shows the melting points, boiling points and specific heat capacity compared to some other molecular compounds
More things, such as metal salts, sugars, amino acids, small nucleic acids and proteins dissolve in water than any other liquid, this is why water is known as the ‘universal solvent’, the reason for this is its polarity, water offers positive and negative charges that other atoms can attach to. All molecules that dissolve in water are called hydrophilic molecules. Non polar lipids such as fats and oils and large polymers such as DNA and large proteins do not dissolve in water, these are called hydrophobic molecules. Water is a solvent that chemical reactions take place in.
The turbidity of water is the amount of particulate matter that is suspended. Clay, silt, plankton and microscopic organisms all cause water to be turbid. It measures the scattering effect that suspended solids have on light, the lower the amount of scattered light, the lower the turbidity.
Specific conductance is the measure of how well water conducts electricity. Pure water will have a very low specific conductance whereas sea water that contains a lot of salt will have a high specific conductance. You can measure the amount of dissolved material in the water using specific conductance.
pH is a measure of how acid or alkali water is. The pH scale goes from 0-14 with pure water being neutral at pH7. pH is the measure of the relative amount of free hydrogen and hydroxyl ions in the water. Any pH lower than 7 is acidic, this means that it has more free hydrogen ions, and any pH above 7 is an alkali, this means that it has more free hydroxyl ions.
Water molecules contain an oxygen atom, but this isn’t what is needed for aquatic animals to survive, a tiny amount of oxygen is actually dissolved into water and that is what they actually breathe. Faster moving water contains more dissolved oxygen than still water; there is also less dissolved oxygen in the summer months.
The hardness of water is determined by the amount of calcium and magnesium in it. It varies throughout the country, areas with harder water may find it difficult to get lather when washing and companies may need to spend money softening the water as hard water can damage equipment.
Water has many properties, and they are all essential in life. Without water we would be able to survive, at the most, only a week. In this assignment I have researched the major properties of water and gone into some depth to explain each one including, water as a solvent, specific heat capacity and specific conductance, all of which help to explain that there is a lot more to water than people may think at first, and it shouldn’t be taken for granted.
References
Books
The Usborne Illustrated Dictionary of Science, C Stockley et al: [1988]
Websites
http://www.ga.water. usgs. Gov/edu/waterproperties.html
www.thewaterpage.com/waterbasics