Properties of Water
Water molecules are dipolar. This means that they contain both slightly positive and slightly negative charges, causing them to attract other polar molecules (ones with a charge). This is called adhesion.
- Plants use adhesion to help transport water against gravity - from their roots to their leaves.
- Our body uses adhesion to transport blood through very small capillaries.
Cohesion refers to the binding together of two molecules of the same type. Water molecules are cohesive: they attract each other due to hydrogen bonding.
- Insects that float on water surfaces rely on surface tension caused by cohesion to do so.
- Cohesion also is useful for water transport in plants, just like adhesion.
Water has important solvent properties. The polar nature of the water molecule means it forms shells around other charged and polar molecules, preventing them from clumping together and keeping them in solution.
- the solvent property of water allows our blood to carry minerals such as iron.
- in plants, the water always carries minerals and nutrients to keep them alive and healthy.
Water has several useful thermal properties:
High Specific Heat Capacity:
Hydrogen bonds restrict motion of water molecules and increase the temperature that water requires for its hydrogen bonds to be broken. Energy is needed for this, meaning the amount of it required is significant.
High Latent Heat of Vaporization:
When a molecule evaporates, it separates from other molecules in a liquid and becomes a vapor molecule. The heat needed for this is called latent heat vaporization. Evaporation therefore has a cooling effect. Because hydrogen bonds must be broken, considerable amounts of heat are needed, making water a good evaporative coolant.
- thermal properties of water help our body temperature to stay stable and not go through drastic changes.
-living organisms in water are able to survive each season for the same reason.