Skip to content
Your progress

Checking your sign-in…

Who's learning?

Each profile keeps its own read lessons, badges, streak, and practice scores on this device.

Lesson 4 of 9

The laboratory thermometer

Show on a big screen

5 min

Text size

Two thermometers, the same length. Why can only one read a hot kettle?

Loading lab…

Two thermometers. Same length.
Step 1 of 4
  1. Two thermometers. Same length.
  2. Clinical: 35 °C to 42 °C.
  3. Laboratory: −10 °C to 110 °C.
  4. Only the wide one reaches a hot kettle.

The rule

Only the laboratory one has a range wide enough for hot water. Range means the lowest and highest numbers on the scale.

A laboratory thermometer is used in science work, not on the body.

It must read icy water and very hot water. So its range is wide: about −10 °C to 110 °C.

The minus sign means colder than zero.

A clinical thermometer stops at about 42 °C. Hot water is above 42 °C. The scale cannot show it.

The range decides what a thermometer can read. Length does not.

Try the lab to finish this lesson.