A thermometer is defined by the Merriam-Webster dictionary as an instrument for measuring temperature. It usually consists of a glass bulb attached to a fine tube of glass with a numbered scale and contains a liquid such as mercury or colored alcohol that is sealed in and rises and falls with changes in temperature. It can be used for various purposes and is essential in different fields of studies worldwide. A number of digital types of thermometers are also available for consumers to choose from and choosing the best one from all the different options can be quite difficult but is possible with a few points to remember.

From its original purpose of measuring body temperature, thermometer uses have increased and varied tremendously. Homes as well as different scientific field are known to sue this device in order to measure body temperature and environment temperature respectively. Such date are used in observations and gathering information. Some of this device's common uses include scientific experiments to control the temperature as a variable, to see how hot food is, or to measure the weather and wind chill.

Sixteen types of thermometers are available in the market to choose from. Among these sixteen types, four are mostly utilized including the outdoor thermometer, clinical thermometer, thermostat and thermocouple. The first type which is the outdoor thermometer is usually used for observation and experiments. Through the expansion and contraction of a liquid in the bulb glass, temperature of the surrounding air can be easily identified. The second type is the clinical thermometer which is the one many of us is familiar with as it is the one used in most homes to monitor and measure body temperature. This is either tympanic – where temperature is measured on the ear – or oral – device is kept in the underarm to measure body temperature- depending on ones preference.

Thirdly is the thermostat which uses expansion and contraction of solids to check temperature. Such is the one used in checking appliance or switch appliances on or off at a preset temperature. Finally is the thermocouple which uses electricity to measure temperature. This on the other hand is popular among individuals who do a lot of temperature measurements in very hot or very low temperature areas such as inside a kiln or blast furnace. It can also be used and connected with a computer easily.

With all the different types of thermometers available, many find it difficult to choose the most appropriate one. Among the first things to look at is the accuracy. No data is considered better than acquiring wrong data. How fast can the thermometer measure the temperature is another important point to consider. This is essential in cooking wherein time is of the essence. Calibration, ease of use, price, sturdiness, timer, and warranty are other factors that should be looked upon before choosing.

Thermometers are indeed useful items in measuring temperature. Having been around since the time of Galileo, these items are truly helpful tools that have been used by many, if not all, individuals, worldwide.

Ivan Dayrit is a pre-school teacher from Germany. Being surrounded by kids everyday, Mr. Dayrit always brings with him a thermometer in the event that any of his students feel sick during class hours.