Galileo thermometer

A Galileo thermometer is a special thermometer that changes the level of the liquid in glass bubbles to show the temperature. The liquid in each bubble is filled with tiny bubbles that react to changes in temperature. When the temperature gets warmer, the liquid becomes lighter and the bubbles rise in the thermometer to show a higher temperature. When it's cooler, the liquid becomes heavier and the bubbles sink to show a lower temperature. You can tell how warm or cold it is by looking at which bubbles are floating or sinking. It's named after the scientist Galileo Galilei, who invented it hundreds of years ago.