Properties of Water

Life on earth is possible because of water and its unique characteristics. Three of these properties are water molecules ability to stick together or stick to other surfaces, waters ability to moderate temperature, and water being an extremely effective solvent. These properties are all a result of hydrogen bonding. All these aspects, and more, combined make water the amazing and unique substance that it is. These characteristics allowed life to begin on earth all those many years ago.

The polarity of the water molecule causes it to be attracted to other polar molecules, like magnets. As a result of this, water molecules have the ability to stick together through cohesion. The hydrogen bonds that connect the water molecules are weak individually, and can very easily be broken, but together they are quite strong. The cohesion of water is responsible for the surface tension of water. Surface tension is the measure of the force necessary to break the surface of a liquid. Where the air and the water meet, the hydrogen molecules face downward, since they can not attach to anything upwards, causing the molecules on the surface to cling together. Because of this water has a high surface tension that allows some insects or small animals to be able to stand/walk on water, such as the water strider. The water molecules also stick to other surfaces through adhesion. Water is adhesive to any substance that is also polar. This is why when some things are put in water they become "wet" and others, which are nonpolar, do not, such as oils. Adhesion is also responsible for capillary action, the attraction of water to a substance, like glass, with surface electrical charges, causing the water levels to rise up the edges of the surface, against gravity, above the previous water level. It has been found that the narrower the tube, the stronger the electrostatic force is, and the higher the water will rise. An example of this is a plant taking water in through its roots from the soil and having its small capillaries bringing the water up through the whole plant all the way to the tip of every single leaf. Everyday there is cohesion and adhesion all around us; bring life to all different types of organisms. With out this property of water life would have never started, and would never have been able to keep going.

Water can absorb heat and give out cooler air, or vise versa. This is how water moderates temperature of the things around it. Water can do this because it has a high specific heat, which is the amount of energy that must be lost or gained for 1g of a substance to change its temperature by 1oC. This high specific heat is related to the hydrogen bonding of water molecules, energy is absorbed to break bonds and released to form them. Thus, putting energy into water barely changes the temperature because the energy is used to in hydrogen bonds disruption and does not speed up the water molecules. Because of its high specific heat,