water.
Lipids share two other characteristics. One
is their clingy, viscous, oily consistency,
which results from the many weak bonds
formed between their long carbon-hydrogen
molecules. And those same molecules are so
bulky that all natural fats, solid or liquid, float
on water. Water is a denser substance due to
its extensive hydrogen bonding, which packs
its small molecules more tightly together.
The Structure of Fats
Fats and oils are members of the same class of
chemical compounds, the triglycerides. They
differ from each other only in their melting
points: oils are liquid at room temperature,
fats solid. Rather than use the technical
triglyceride to denote these compounds, I’ll
use fats as the generic term. Oils are liquid
fats. These are invaluable ingredients in
cooking. Their clingy viscosity provides a