Thermometer
A lab thermometer is a long glass tube that measures how hot or cold something is.
What is it for?
It tells you the temperature of a liquid in degrees Celsius, for example while you are heating water.
How to use it
Put the bulb end in the liquid without touching the sides or the bottom, wait a moment, then read the scale.
🥽 Safety tip: Lab thermometers break easily, so lay them down where they cannot roll off the table.
Fun fact from Fizzy: Water boils at 100 degrees Celsius at the seaside, but at the top of a high mountain it boils at a lower temperature.
How it works
Inside the glass is a thin column of coloured liquid, usually alcohol with red or blue dye. When it warms up, the liquid expands and creeps up the tube. When it cools, it shrinks back down. The scale tells you what temperature each height means.
Older thermometers used silvery mercury, but mercury is poisonous, so most schools now use alcohol or digital thermometers instead.
Where you would see one
Lab thermometers usually measure from about minus 10 to 110 degrees Celsius. Doctors, cooks, weather stations and fish-tank owners all use thermometers too, though theirs are made for different temperature ranges.