Difference between Heat and Temperature | Concept and Definition

January 11, 2021

Hello, learner! Have you ever tried rubbing your palms together in winter? By doing this we feel a little warm in our palms. Right? Yes, it happens but why?

Well, this is due to friction between our palms, which generates heat and we feel comfortable in winter.

What is Heat? 🔥

Heat is a form of energy that is generated by the random motion of molecules and it flows from a warmer to a colder body.

Everything you see is made of small molecules. They are continuously in motion. Their motion may not be in a definite direction. They can move in any direction. This motion or vibration generates heat. Heat is the total energy of the motion of the molecules of a substance.

In warm objects, molecules vibrate faster than the molecules of cold objects. Therefore they transfer energy to the slower molecules, and that's why heat flows from warm to cold bodies. Due to this transfer of thermal energy warm body becomes cool and a cool body becomes warm. This transfer happens until both bodies occupy the same temperature.

Vibrational energy is termed as heat content. This heat content makes a body hot or cold. Greater heat content, hotter will be a body.

What is Temperature? 🌡️

Temperature is the degree of hotness or coldness measured on a definite scale.

The temperature is the average kinetic energy possessed by the particles of the substance. If we double the temperature, then its average kinetic energy will be also doubled. When particles move more quickly, the temperature is higher and an object feels warmer. When particles move more slowly, the temperature is lower and an object feels cooler.

Temperature is measured with a thermometer. A thermometer shows how hot or cold something is relative to two reference temperatures, usually the freezing and boiling points of water.

Temperature and Thermal Energy

Normally we think that an object with a higher temperature will have higher thermal energy. But is it always true? No, it's only possible when both objects have the same mass. Temperature affects thermal energy but it's not thermal energy. Confused? 🤔 Let me give you an example for a better understanding of this statement.

Suppose you have a cup of tea ☕ or coffee or milk whatever you want. And I have a bathtub 🛁 full of hot water. The temperature of your tea is 60°c and the water in my bathtub is 30°c. What do you think? Which one has more thermal energy? Well, if your answer is the water of my bathtub then you are right. But why? Mass of water is larger than tea. So bathtub water has more particles, more particles mean that more random motion, which means more thermal energy. But in your cup of tea, less mass so less thermal energy. In the cup of tea, particles move faster than the particles of hot water in the bathtub. That's why its kinetic energy is more and the temperature is greater.

Now you can understand that temperature and object's mass both affects thermal energy.

What can happen when Heat is added to matter?

Two things can happen if you heat substance-

The heat will give energy to the matter. Therefore particles will move faster. And due to the increased speed of particles, kinetic energy increases, and the temperature of the body also increases.
Another thing that can happen is a phase change. If we heat water at 100°c, water molecules become to leave in the vapour state.

During phase change temperature is not increased, because all given heat is consumed in converting the phase, therefore kinetic motion is not increased, and hence the temperature remains the same.

What can happen when Heat is taken away from the matter?

Two things can happen in process of removing heat from the matter-

The molecules of matter will slow down as the energy is being taken away, and hence the temperature of the matter will become lower.
A phase change can happen during the removal of heat. For example, if we take away heat from the water, it becomes ice. 🧊