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Water (2.1/2.2)

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2.2 Water

Nature of science:

Use theories to explain natural phenomena—the theory that hydrogen bonds form between water molecules explains the properties of water. (2.2)


Water molecules are polar and hydrogen bonds form between them.

Hydrogen bonding and dipolarity explain the cohesive, adhesive, thermal and solvent properties of water.

Substances can be hydrophilic or hydrophobic.

Applications and skills:

Application: Comparison of the thermal properties of water with those of methane.

Application: Use of water as a coolant in sweat.

Application: Modes of transport of glucose, amino acids, cholesterol, fats, oxygen and sodium chloride in blood in relation to their solubility in water.


Students should know at least one example of a benefit to living organisms of each property of water.

Transparency of water and maximum density at 4°C do not need to be included.

Comparison of the thermal properties of water and methane assists in the understanding of the significance of hydrogen bonding in water.


There are challenges for the increasing human population in sharing water resources equitably for drinking and irrigation, electricity generation and a range of industrial and domestic processes.

Theory of knowledge:

Claims about the “memory of water” have been categorized as pseudoscientific. What are the criteria that can be used to distinguish scientific claims from pseudoscientific claims?


Aim 6: Probes can be used to determine the effect of different factors likely to influence cooling with water.

Essential idea: Compounds of carbon, hydrogen and oxygen are used to supply and store energy.

Jessica Clark,
Sep 13, 2013, 7:33 AM