Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Fats and Oils

Fats and Oils, group of naturally occurring organic compounds called triglycerides—esters comprised of three molecules of fatty acids and one molecule of the alcohol gylcerol. They are oily, greasy, or waxy substances that, in their pure state, are normally tasteless, colorless, and odorless. Fats and oils are lighter than water and are insoluble in it; they are slightly soluble in alcohol and are readily dissolved in ether and other organic solvents. Fats are soft and greasy at ordinary temperatures, whereas fixed oils—as distinct from essential oils and petroleum—are liquid. Some waxes, which are hard solids at ordinary temperatures, are chemically similar to fats).

he fatty acids in food products are divided into three categories based on their chemical composition. In a saturated fat molecule, every carbon atom bonds with two hydrogen atoms. In a monounsaturated fat molecule, one pair of hydrogen atoms is missing. In a polyunsaturated fat molecule, more than one pair of hydrogen atoms is missing. Foods with large amounts of saturated fats tend to raise cholesterol levels in humans, while foods with unsaturated fat tend to lower cholesterol levels.