Energy, whether kinetic, stored, or thermal, is a property of an object. Gravitational field energy is a property of the gravitational field. Work and heat are means of energy transfer. Work is transfer by mechanical means. Heat is transfer between two objects with different temperatures. Examples of work are you throwing a ball, a slingshot launching a stone, a ball being caught in a mitt. Examples of heat are your hand being warmed by putting it in hot water, a bottle of soda being cooled in a refrigerator, and Earth’s surface being warmed by sunlight.