After scientist Daniel Fahrenheit came up with the blueprint for the modern thermometer 300 years ago, he came up with the Fahrenheit scale to measure temperature. On his scale, water freezes at 32 degrees and boils at 212 degrees. Later, astronomer Anders Celsius invented a scale where zero degrees is freezing and 100 degrees is boiling. The Celsius scale now is used in most countries, but the United States still uses Fahrenheit – just because it wants to.
Class discussion: Which temperature scale would you rather use? Would you stick with Fahrenheit because it is familiar? Or, does the Celsius scale seem more logical and compatible with a metric system based on multiples of 10? Why should a temperature scale be based on the freezing and boiling points of water? Why do we use multiples of 10 in our decimal number system? Why divide time into 60-second minutes, 60-minute hours and 24-hour days? Would you ever change that into a decimal system?