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.


Vinegar, sour-tasting condiment and preservative prepared by two successive microbial processes, the first being an alcoholic fermentation effected by yeasts and the second an oxidation of alcohol by Acetobacter, a genus of aerobic bacteria.

Regulations of the U.S. Food and Drug Administration prescribe that the unmodified name vinegar apply only to the product derived from apples and that this product contain not less than 4 g of acetic acid in 100 ml of vinegar. Vinegar also contains small quantities of ash, sugars, phosphoric acid, alcohol, and glycerol. A quick method of manufacture is to pour fermented apple cider containing about 10 percent alcohol over wood shavings while air is blown through the mixture. The resulting liquid is then clarified and filtered. Malt vinegar is preferred in Britain, and wine vinegar in continental Europe. Other varieties of vinegar are produced from beetroot and alcoholic spirits; and it is sometimes flavored, for example, with tarragon, dill, or other herbs.