Question: How does energy transfer? How does the energy change from one type to another?

Thomas Ashton answered on 9 Jan 2017:

Energy can transfer in many different ways, and is a fundamental process governing all aspects of Science. On a most basic level, you could eat your breakfast and then get up, go to the park, and play a game of football. This is because your food is digested and converted into usable biological compounds by chemical processes which are delivered to your muscles, brain and different organs to help you achieve your daily tasks. So the energy started as potential chemical energy (stored in your food) and ended up as kinetic energy (your movement).

The same theory applies to fundamental energy transfer. Let’s say we microwave some food. The microwave irradiation causes molecules, such as water, in the food to rotate (kinetic). This in turn causes the molecules to knock into each other causing friction. As we all know (from ill-advised sliding across carpet on our knees) friction can cause heat. So, in our microwaved food the molecules produce heat and we end up with our hot meal. In this example we have gone from microwave radiation, to kinetic energy, to molecular friction and then to heat.