Thermometer

Definition

A thermometer is a device used to measure and indicate the temperature of a substance or environment. It is a fundamental tool in the study of temperature and thermal equilibrium, heat transfer, and mechanisms of heat transfer.

5 Must Know Facts For Your Next Test

1. Thermometers can be based on various principles, such as the expansion of liquids, gases, or solids, the change in electrical resistance, or the emission of infrared radiation.
2. The most common type of thermometer is the liquid-in-glass thermometer, which uses the expansion of a liquid, typically mercury or alcohol, to indicate temperature.
3. Thermometers are essential for measuring and monitoring temperature in a wide range of applications, including scientific research, medical diagnosis, and industrial processes.
4. The temperature scale used in a thermometer can be Celsius, Fahrenheit, or Kelvin, with Celsius and Kelvin being the most commonly used in scientific contexts.
5. Thermometers can be calibrated to provide accurate temperature measurements by comparing their readings to a known standard, such as the freezing and boiling points of water.

Review Questions

• Explain how a thermometer can be used to determine thermal equilibrium between two objects.
  • When two objects are placed in contact, a thermometer can be used to measure the temperature of each object. If the temperatures of the two objects are the same, they are said to be in thermal equilibrium, meaning there is no net heat transfer between them. By using a thermometer to measure the temperatures of the objects, you can determine if they have reached thermal equilibrium.
• Describe how a thermometer can be used to measure the specific heat capacity of a substance.
  • In the context of calorimetry, a thermometer can be used to measure the temperature change of a substance when it absorbs or releases a known amount of heat. By combining the temperature change, the mass of the substance, and the amount of heat added or removed, the specific heat capacity of the substance can be calculated using the formula $Q = m c \Delta T$, where $Q$ is the heat, $m$ is the mass, $c$ is the specific heat capacity, and $\Delta T$ is the temperature change. The thermometer is essential for accurately measuring the temperature change in this process.
• Analyze how the type of thermometer used can affect the measurement of heat transfer mechanisms, such as conduction, convection, and radiation.
  • The type of thermometer used can impact the measurement of heat transfer mechanisms. For example, a contact thermometer, such as a liquid-in-glass thermometer, may not accurately measure the temperature of a surface undergoing radiative heat transfer, as it relies on conductive heat transfer to the thermometer. In contrast, an infrared thermometer can measure the surface temperature more accurately in this case, as it detects the infrared radiation emitted by the surface. Similarly, the placement and response time of a thermometer can affect its ability to capture the dynamics of convective heat transfer. The choice of thermometer must be carefully considered based on the specific heat transfer mechanism being studied to ensure accurate and meaningful measurements.

Related terms

Temperature:

Temperature is a measure of the average kinetic energy of the particles in a substance, which determines the direction of heat transfer.

Thermal Equilibrium:

Thermal equilibrium is the state in which two or more objects or systems have the same temperature, and no net heat transfer occurs between them.

Calorimetry:

Calorimetry is the measurement of the heat absorbed or released during a physical, chemical, or biological process.