Archive for the ‘science’ Category

Galileo Thermometer

March 4, 2014

Now you’d think, if you had a Galileo thermometer that the great man had invented the device. You’d be wrong. Galileo understood the principles on which the device is based and it was followers of his, including Torricelli who invented the device and named it in honour of Galileo Galilei. That was back in 1666. The device is slow to respond to changes in temperature. Its alternative name was ‘The Slow Thermometer’.

Now forget them for more than 300 years and then decide that with the addition of a bit of colour, they’ll make wonderful scientific toys for the man who needs for nothing. That’s what the London Science Museum started doing in 1990 and it is one of their attractive devices that I have.


The column of liquid contains a number of glass globes which contain coloured liquid. These rise or fall according to temperature. They have a metal tag on the bottom – a vital part of the balancing and this tells us the temperature at which they fall. My ‘Galileo’ is designed for quite warm rooms and only the bottom, 18oC globe has fallen. The globes go up in two degree gaps so I know the temperature is between 18 and 20. If it reached 20o then the next globe would fall. It seldom does in my house during the winter.

However, I can make more globes fall by warming the device with a hand.


There we are, the 18, 20 and 22 degree globes are ‘off the top’. It is registering a mix of room and my hand temperature. As a human, my body temperature is about 37oC.

What a lovely device. It sits on a shelf, normally, and allows me to argue with my wife when she tells me it is too hot in the room.

This is no advert, but they are still obtainable from the Science Museum.