• Thermometer is the most common instrument to measure temperature. There are various kinds of thermometers.
  • Some of them are like glass tubes which look thin and are filled with some kind of liquid. Mostly Alcohol and Mercury are used in thermometers as they remain in liquid form even with a change of temperature in them.
  • A small change in the temperature causes change in volume of a liquid. However, this form of effect is maximized when liquid expands within the thin tube of thermometer.
  • Thermometers measure the temperature due to the thermal expansion. Increase in the volume of substance because of increase in the temperature is known as Thermal expansion.
  • Different types of substance expand in different quantities for a given set of temperature change. When a thermometer is introduced into an hot material, the liquid within the thermometer tends to expand and then rises.
  • Thus, we measure this temperature by measuring expansion of an liquid in thermometer.

Temperature Units:

Some units of temperature, degrees Fahrenheit and degrees Celsius. Kelvin is another unit of temperature that is very handy for many scientific calculations, since it begins at absolute zero, meaning it has no negative numbers. Relation between Fahrenheit, Celsius & Kelvin

Fahrenheit to Celsius:


Celsius to Kelvin:



Effects of Temperature:

An increase or decrease in temperature causes various changes in the physical and chemical processes of life. Some of those are given below-

  • It affects the solubility, density, vapor pressure, physical properties of various materials along with the electrical conductivity
  • The rate of a chemical reaction is also affected by the temperature.
  • The thermal radiations from the surface of objects are also affected by temperature.


Thermometers are used to measure temperature. Below is a list of some scenarios in which a thermometer might be used.

– To measure the outdoor temperature.

– To measure body temperature during a physical exam at the doctors.

– To measure body temperature when someone is ill to determine if he/she has a fever.

– To measure the temperature of an oven.

– To measure the temperature of meat after it is cooked to make sure that it is warm enough to have killed off bacteria and, therefore, safe to consume.

– To measure the temperature of a pool.

– To measure the temperature of sugar when making candy. This is of utmost importance because, if the sugar becomes too warm, then it can burn and will not crystallize.

– To measure the temperature of an incubator for a premature infant or for growing bacterial specimens in the lab

I am scientist

I am scientist is a result of small effort to make huge impact on children. To stimulate the curiosity of young scientist towards science. Each idea will start with a experiment followed by reasoning the result , scientific learning, vocabulary (recap the big words used), useful reference website and books, along with free downloadable worksheets.

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