If you look around your house, you will find lots of different devices whose goal in life is to either detect or measure changes in temperature:

• The thermometer in the backyard tells you how hot or cold it is outside.
• The meat and candy thermometers in the kitchen measure food temperatures.
• The thermometer in the furnace tells it when to turn on and off.
• The thermometer in the oven lets it keep a set temperature (hot).
• The thermometer in the refrigerator lets it keep a set temperature (cold).
• The fever thermometer in the medicine cabinet measures temperature accurately over a very small range.

In this article, we will look at the different thermometer technologies used today and understand how they work. You will also get to build your own thermometer!