VALENCIA. Both olive oil and drinking water are basically constituted by a specific type of molecule-triacylglycerols (commonly known as triglycerides) in the former case and water in the latter case. Water and olive oil do contain dissolved substances, but in such small quantities that they hardly affect these liquids in the cooling process.
While in water we only find one kind of molecule, in olive oil we find different types of triglyceride molecules, and that is why, water's freezing point is 0ºC, while olive oil's freezing point ranges from 23ºC to 5.5ºC. In the liquid state, water molecules -H2O- are in continuous motion: they spin around, move and bounce around.
In the gas state, molecules are very far from each other, but in the liquid state they are very close to one another due to the forces of attraction between them. When water gets cold, molecules gradually reduce their motion speed, until it reaches 0ºC, when the liquid solidifies.
In ice, water molecules do not move, nor spin around -they remain calmed and organised. However, in ice there is still movement: hydrogen atoms swing around in their equilibrium state, and the lower the ice temperature is, the less they oscillate. The freezing point of a liquid depends on the magnitude of the attractive forces between the molecules that constitute it.
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Department of Inorganic Chemistry and Institute of Materials Science
Science Park, University of Valencia