What are Vaccines? By Dr Ananya Mandal, MD. There are several diseases like Diphtheria, whooping cough (pertussis), measles, mumps, Yellow fever, small pox and German measles (rubella) that are unfamiliar to many these days.
nuclear energy energy that can be liberated by changes in the nucleus of an atom (as by fission of a heavy nucleus or by fusion of light nuclei into heavier ones with accompanying loss of mass).
But what is energy? Answering that question is surprisingly hard, because it comes in a lot of different forms. Energy can be stored in food. Energy can be related to movement. But what about nuclear energy, or sound energy, or light energy? These all seem a little bit different. The physics definition of energy is that it's the ability to do work. Energy is like a currency that can be spent when we want to do work. If we have plenty of energy in our bodies, we can apply more forces over longer distances and do more work than if we had less energy.