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.

Dietary Sources of Antioxidants

Vitamin C, also known as ascorbic acid, is a well known antioxidant that may prevent cataracts and cancers of the stomach, throat, mouth, and pancreas. It may also prevent the oxidation of LDL cholesterol, lowering the risk of heart disease. Foods that are high in vitamin C include strawberries, oranges, broccoli, and brussels sprouts.

Beta-carotene absorbs free radicals that target molecules in the cell membrane. Studies suggest that in addition to reducing the risk of cataract, cancer, and heart attack, beta-carotene may also reduce the risk of stroke. Beta-carotene occurs naturally in orange-colored fruits and vegetables and dark green, leafy vegetables. Some of the best sources of beta-carotene are sweet potatoes, spinach, and carrots.

As an antioxidant, vitamin E may also protect from heart disease and cataract and may strengthen the immune system. Good sources of vitamin E include wheat germ oil and sunflower seeds.