General equation of heat transfer

Imagine you have a toy stove and you want to cook some food on it. When you turn on the stove, it starts to get hot and the heat spreads from the stove to the pot on top of it. This is because heat is like a special kind of energy that likes to move from hot things to cool things.

Now, let's talk about the equation for heat transfer. This equation helps us understand how heat moves from one place to another.

The equation looks like this:

Q = U * A * ΔT

Don't worry if that looks scary, we will break it down step by step.

Q stands for "heat energy" and is measured in units called Joules (J). This tells us how much heat energy is being transferred.

U stands for "heat transfer coefficient" and is a value that tells us how quickly heat will move through a material. For example, metal is a good conductor of heat, so it has a high U value, while plastic is a poor conductor of heat, so it has a low U value.

A stands for "surface area" and tells us how much surface there is for heat to transfer across. If you have a bigger pot on your stove, it will have more surface area and can transfer more heat than a smaller pot.

ΔT stands for "temperature difference" and tells us the difference in temperature between the hot object and the cool object. For example, if the stove is at a temperature of 200 degrees Celsius and the pot is at 100 degrees Celsius, the temperature difference ΔT is 100 degrees Celsius.

So, putting it all together, the equation tells us how much heat energy (Q) is transferred between two objects when there is a temperature difference (ΔT) and a certain amount of surface area (A) and heat transfer coefficient (U).

In summary, the equation for heat transfer helps us understand how quickly heat energy moves from hot things to cool things, depending on factors like surface area and temperature difference.