When you make Mac and Cheese you are coming face to face with many different types of energy. Energy is the capacity to do work or move an object. Energy can be transformed and this is proven when you make mac and cheese. The macaroni has chemical potential energy. And by using thermal energy the mac and cheese is cooked and energy is released. The macaroni is changed because of work energy. Work done on a system by external forces changes the energy system. Also if you hold a piece of macaroni in the air it has potential energy and when you drop it the kinetic energy increases as the potential energy decreases making the mechanical energy zero.