Thermometers are devices used to measure temperature. There are many different types of thermometers, which can be used to measure air, water, or body temperature, depending on their design. Thermometers may also be used in cooking, such or candy or meat thermometers.
The history of thermometers is not a very long one. Thermometers were first invented in the early 1500s, although who exactly was the first to invent the thermometer is not certain. One of the inventors thought to be among the first to develop a thermometer was Galileo Galilei. His thermometer came to be known as the Galileo thermometer. Its design is quite different from other thermometers, consisting of a glass tube filled with water, in which small glass balls float. The glass balls are filled with alcohol, or another liquid that is less dense than water, and each is marked with a temperature. Some of the balls will float to the top, while others will remain at the bottom. The lowest floating ball indicates the current temperature.
One of the most common thermometers is the mercury thermometer. A well-known example of a mercury thermometer is the classic glass thermometer used to read body temperature. Although these thermometers contain very little mercury, many doctors now recommend that they not be used, in favor of less hazardous and more accurate digital thermometers. Mercury thermometers are still widely used in meteorology, but they cannot be used in areas where the temperature will fall below 37 degrees Fahrenheit.
Indoor/outdoor thermometers are also extremely popular for home and garden use. These thermometers are generally designed to be functional as well as decorative. Many have designs of an outdoors nature, such as birds, butterflies, or flowers. Outdoor thermometers are more common, especially for avid gardeners. Since many people have central heating and air conditioning systems, they can simply use their thermostat to tell the current indoor temperature. However, even these people can enjoy indoor thermometers for decorative use.
There are many online web sites that give good directions on how to build a thermometer. This can be a fun project to do with children, as it is both creative and educational. Such a project is ideal for the long summer vacation from school, to keep your child from boredom, and keep his or her mind sharp and ready to learn. A trip to the local library can also give you information on building a thermometer, and might encourage your child to pick up other books while you are there.