What is Heat? | Definition, Types, Formula & Examples

What is Heat?

Heat is the transfer of energy from one object to another due to a temperature difference. Heat can be measured in joules, BTU (British thermal units), or calories.

Temperature and temperature are closely related, but they are not the same. The temperature of an object is determined by the speed at which its molecules are moving. The faster the molecules move, the higher the temperature. We say that an object with a high temperature is hot and an object with a low temperature is cold.

Transferring of Heat

When two elements combine or touch, their molecules transfer energy called heat. They will try to get to a point where they will both be at the same temperature. This is called balance. Heat will transfer from a hotter object to a cooler object. The molecules of the hotter object will slow down and the molecules of the colder object will speed up. Eventually, they will reach a point where they will have the same temperature.

It happens around you all the time. For example, when you take an ice cube and put it in a cup of hot soda. The ice cube will heat up and melt, while the soda will cool.

Hot Objects Expand

When something gets hotter, it expands or grows. At the same time, when something gets colder, it shrinks. This property is used to make mercury thermometers.

The thermometer line is actually liquid mercury. As the liquid becomes hotter, it expands and rises in the thermometer to indicate a higher temperature. It is the expansion and contraction caused by temperature that allows the thermometer to work.

Heat Conduction

When heat is transferred from one object to another, it is called conduction. Some materials conduct heat better than others. For example, metals are good conductors of heat.

We use metal in pots and pans for cooking because it will quickly transfer heat from the flame to our food. Fabric, like blankets, is not a good conductor of heat. Because it’s not a good conductor of electricity, blankets keep us warm at night because it doesn’t conduct our body heat to cold air.

Matter Changing State

Heat has an effect on the state of matter. Matter can change state depending on temperature or temperature. Depending on its temperature, matter can assume three states: solid, liquid, and gas. For example, if water is cold and its molecules move very slowly, it will be a solid (ice).

If it heats up a little, the ice will melt and the water will become liquid. If you add a lot of heat to the water, the molecules will move very quickly and it will become a gas (vapour).