David Lips, age 10, of Atlanta, Ga., for his question:

How hot is a degree?

We measure temperature by Fahrenheit or Centigrade degrees. The everyday thermometer is set to record temperature from the freezing to the boiling point of water, with a few degrees above and below this range.

Temperature is recorded on a scale which, for convenience, is divided into small sections called degrees. The temperature range between freezing and boiling water could be divided into any number of degrees we might choose, for the ladder of degrees on the thermometer is a man‑made device.

The Centigrade scale has 100 degrees between the freezing and boiling points of water. The Fahrenheit scale has 180 degrees. Hence, a centigrade degree is 100th part of the temperature range between freezing and boiling water and a Fahrenheit degree is five‑ninths of a centigrade degree.