Day 265~366

The small calorie or gram calorie (symbol: cal) is the approximate amount of energy needed to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere. The large calorie or kilogram calorie (symbol: Cal), also known as the food calorie and similar names, is defined in terms of the kilogram rather than the gram. It is equal to 1000 small calories, 1 kilocalorie (symbol: kcal). Although these units are part of the metric system, they have been superseded in the International System of Units by the joule. One small calorie is approximately…

Day 264~366

The numeric system represented by Roman numerals originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers in this system are represented by combinations of letters from the Latin alphabet. The use of Roman numerals continued long after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced in most contexts by the more convenient Hindu-Arabic numerals; however, this process was gradual, and the use of Roman numerals persists in some minor applications to this day. The numbers 1 to 10 are…