Donna Kotulka, age 11, of Allentown,Penn.,

What is a B.T.U. ?

B.T.U. or Btu is the shortened form of British thermal unit ‑ arid the word thermal means heat. The Btu, then, is a unit for measuring heat. It was worked out by the British and is used in English‑speaking countries where the pound is used as a measure of weight. Scientists and countries using the metric system use the calorie as their heat ­measuring unit.

The Btu is the heat required to raise one pound of pure water one Fahrenheit degree. We use it to measure the quality of fuels. A poor quality of coal may have a value of 9,000 Btus, meaning it yields 9,000 of these units as one pound is burned. A good quality coal may yield 16,000 Btus per pound.