Energy is in everything and every living thing needs energy to live. Our primary source of energy is the sun. It fuels plants that in turn fuel animals. But people use other sources of energy. Energy cooks our food, warms our homes, lights our streets, brings us television and powers our cars. Energy is defined as the ability to do work, and we use energy to work. Energy comes in different forms: heat (thermal), light (radiant), mechanical, electrical, chemical and nuclear. Stored energy is potential energy and moving energy is kinetic energy. Some energy sources are renewable, like wood (the first source for fire), solar, geothermal (inside the earth), biomass(from plants) and wind. Water (hydrothermal) is a valuable natural resource, but must be conserved wisely. Some sources are non-renewable like coal and oil. Non-renewable sources cannot be replenished or take millions of years to replenish.

People need to use renewable energy sources to live sustainably!