In thermodynamics, temperature and heat are very important ideas. Each of these has special units that we use to measure them. Knowing how these units work is key for solving problems and doing calculations in this field.

Temperature:

• The main unit of temperature in the International System of Units (SI) is called the Kelvin (K).

• One Kelvin is a tiny part (1/273.16) of the temperature point where water can exist in three states: solid, liquid, and gas, which is around 0.01 °C (degrees Celsius).

• We also use other temperature scales like Celsius (°C) and Fahrenheit (°F):

  • To change Celsius to Kelvin, you can use this formula:

    $K = °C + 273.15$

  • To change Celsius to Fahrenheit, use this:

    $°F = \frac{9}{5} °C + 32$

Heat:

• The basic unit of heat in the SI system is the joule (J). Heat is the energy that moves from one place to another because of a temperature difference.

• Another unit for measuring heat is the calorie (cal), which is often used in cooking and nutrition. One calorie is the amount of heat needed to raise the temperature of one gram of water by one degree Celsius:

  $1 \, \text{cal} = 4.184 \, \text{J}$

• In many industries, we often talk about kilocalories (kcal), where 1 kilocalorie equals 1000 calories.

Work:

• Work (W) is connected to temperature and heat, even though it doesn’t measure them directly. Work is also measured in joules (J). The first law of thermodynamics tells us about the relationship between heat added to a system (Q), work done by the system (W), and the change in internal energy (ΔU):

  $\Delta U = Q - W$

By learning about these units, students can understand the basic ideas about temperature and heat. This knowledge helps build a strong base for future studies in subjects like physics and engineering.