Paragraph on “Thermometer” complete paragraph for Class 9, Class 10, Class 11 and Class 12

Thermometer

We often ask ourselves or someone, how hot or how cold it is. The answer to this simple question would not have been possible without the thermometer. In 1592 Galileo made a device which could measure temperature, it was a crude version of the modern thermometer and was called an ‘air thermoscope’. This device had a glass tube open at one end and a glass bulb at the other. The bulb of the tube was heated thus forcing the air out of the tube, then the open end of this tube was placed in water. As the air in the tube cooled, water was sucked in. Any subsequent changes in temperature were then noted from the changing level of water in the tube. This device proved inaccurate since changes in atmospheric pressure also effected the water level. The modern day thermometer uses a sealed tube with a glass bulb filled with a liquid instead of the open ended one and is more accurate.