Science defines energy as the ability to do work.
Energy is all around us, and comes in different forms – heat (thermal), light (radiant), mechanical, electrical, chemical and nuclear energy. We use energy for everything we do, from running to catch a bus to cooking a pizza, from flying a kite to sending astronauts into space! Although there are many forms of energy, most can be put into two categories, kinetic (motion) and potential (stored). Perhaps your class can carry out a project examining different forms of kinetic and potential energy in more detail?
Energy is present in every living system.
Almost everything you eat can be traced back through the food chain to the sun. Energy changes form at each step in the food chain. Energy flow in living systems enables humans and other organisms to survive. Living systems use energy to grow, change, maintain health, move, and reproduce. The amount of energy that makes it from one level in the food chain to the next can vary, but will generally average about ten percent. Human societies, like natural ecosystems, need energy to organise and maintain themselves.