Absolute Zero

During the seventeenth century in England, outside temperatures reached so low during the winter that it is actually considered to be a “mini ice age” by scientists today. During this time, people were still somewhat fatalistic and believed that cold was an act of god, and that people should just leave it alone. That was until an alchemist named Cornelius Drebbel came along. Drebbel bet the King he could turn summer into winter by chilling the air in the Great Hall of Westminster. Drebbel did so by using ordinary table salt, which will lower the temperature at which ice melts, to keep a freezing mixture as cold as possible while he ran warm air over it. Because of his elaborate design, Drebbel’s invention worked and he invented the first “air conditioning unit” of his time. However, Drebbel’s invention was never documented and he was never given credit.

The infamous question, “what is cold?” is a question that would haunt scientist Robert Boyle for years. Boyle was famous for his experiments on the nature of air and was also known as a master of cold. During Boyle’s time, it was believed that cold was an actual substance that bodies take in and give off as their temperature adjusts. However, Boyle remained unconvinced as far as this theory was concerned. To prove his point, he performed an experiment on water. He filled a barrel with water and weighed it. He then let it freeze and weighed it again, only to find that it weighed the same. With this information, Boyle concluded that there was no outside substance making the water cold. He determined that the particles of the water were simply moving farther apart, causing the barrel to expand. Not only was Boyle the first scientist to prove that cold was not a substance, but he was also among the first to use an accurate thermometer.

Accurate thermometers did not exist until the mid 17th century. They used alcohol, as opposed to mercury, and had no universally accepted way of measuring temperature. David Fahrenheit was the first scientist to use a fixed temperature scale. He used fixed points in nature such as ice, for the lower ranges, and human body temperature, for the higher ranges. A more accurate version of the thermometer, developed by Anders Celsius, later came out. His version used two fixed points and the space in between was divided up into 100 parts. His lowest point was the boiling point of water and his highest was the freezing point. This scale was later inverted to give us modern day Celsius. However, this scale also posed the question, how low can you go?

A French physicist by the name of Amontons discovered that pressure and temperature dropped at the same rate, so the temperature at zero pressure was as low as you could possibly go with temperature, or absolute zero. He found this number to be approximately –273