Heat energyMost of us use the word heat to mean something that feels warm, but science defines heat as the flow of energy from a warm object to a cooler object.Actually,heat energyis all around us in volcanoes, in icebergs and in your body. Allmattercontains heat energy.Heat energy is the result of the movement of tiny particles calledatoms,moleculesor ions in solids, liquids andgases. Heat energy can be transferred from one object to another, and the transfer or flow due to the difference intemperaturebetween the two objects is called heat.For example, an ice cube has heat energy and so does a glass of lemonade. If you put the ice in the lemonade, the lemonade (which is warmer) will transfer some of its heat energy to the ice. In other words, it will heat up the ice. Eventually, the ice will melt and the lemonade and water from the ice will be the same temperature. This is known as reaching a state ofthermal equilibrium.Moving particlesMatter is all around you. It is everything in theuniverse anything that has both mass andvolumeand takes up space is matter. Matter exists in different physical forms solids, liquids and gases.All matter is made of tiny particles called atoms, molecules and ions. These tiny particles are always in motion either bumping into each other or vibrating back and forth. It is the motion of particles that creates a form of energy called heat (or thermal) energy that is present in all matter.