Question

why did coconut oil thicks in winter

Answer 1

Coconut is mainly saturated fatty acid. It solidifies at lower temperature. The reason for this is because saturated fats (animal fats/ coconut oil) have mainly hydrogen atoms along the hydrocarbon chains and when they come close to other molecules they can form many van der waals forces between it and the other molecule. It requires more force to melt the substance and therefore, it melts at higher temperatures and so are solid at room temperature.
Unsaturated fats (plant fats/ oils) are similar but they often have kinks in the chains which cannot cram as many into a given volume and so there are less van der waal’s forces and so less force is required to remove one from the other e.g. it melts at lower thermal energy levels and at room temperature are liquid and therefore refer to as oil. “ Fluidity of liquid can change with the degree of unsaturation”.
Unsaturated fats have one or more double bonds. Increases in the number of double bond progressively decreases the melting point. In general, the melting point of unsaturated fatty acids are lower than that of saturated fatty acids. In unsaturated fatty acids, a cis double bond forces a knik in the hydrocarbon chain. Fatty acids with one or several such kink can not pack together as tightly as a fully saturated fatty acids can and there interaction with each other therefore, weak.
Because it takes less thermal energy to dissociate these poorly ordered aaray of unsaturated fatty acids, they have significantly lower melting point than saturated fatty acids

Answer 2

Every fat and fatty acids has a range of temperatures at which it freezes. It is in fact the main distinguishing point between fats and oils. The coconut oil thickens during winter because it is a more saturated fat.