Worlds of David Darling > Children's Encyclopedia of Science > Between Fire and Ice > Glossary The Science of Heat a book in the eXperiment! series by David Darling
alcohol A clear liquid, with a low freezing point, that is commonly used in both indoor and outdoor thermometers. It is often stained red to make it easily visible. bimetallic strip Two different metals joined together to form a long, thin strip. When heated, one of the metals expands more than the other and so causes the strip to bend. This can be used as a means to control the heating and cooling of various devices. Celsius One of the two main scales of temperature in common use. On the Celsius scale, the freezing point of water is 0° and the boiling point is 100°. change of state This happens when a substance goes from one of its three possible states – solid, liquid, or gas – to another. condensation The process of changing from a gas to a liquid. conduction One of the three ways by which heat can travel from one place to another. It involves the transfer of heat energy from one molecule to the next molecule. conductor A substance or object that lets heat pass easily through it. convection One of the three ways by which heat can travel from one place to another. It involves the movement of parts of a gas or liquid as they become heated up and cooled down again. energy The ability to do work or cause movement. evaporation The process of changing from a liquid to a gas at temperatures below the boiling point of the liquid. Fahrenheit One of the two main scales of temperature in common use. On the Fahrenheit scale, the freezing point of water is 32° and the boiling point of water is 212°. Freon A substance used in refrigerators that changes easily from liquid to gas and back again. infrared Heat radiation. insulator A substance or object that does not let heat pass easily through it. mercury The only metal that is a liquid at normal room temperature. Used commonly in thermometers, it has the advantage that it will not stick to glass. molecule The smallest part of a substance that can exist and still have the properties of that substance. oral thermometer A kind of mercury thermometer used to take the temperature of the human body. Its scale covers only the range of temperatures found in human beings. radiation One of the three ways by which heat can travel from one place to another. It involves the movement of heat by electromagnetic radiation. steam Tiny droplets of water that form when water vapor condenses. thermometer A device used for measuring temperature. water vapor The gas that water turns into. Compare this with steam. |