1 Without its atmosphere, Earth would be a very different planet. 2  Gases in the atmosphere allow plants to photosynthesize and animals and plants to engage in respiration. 3  Water vapor, which is an atmospheric gas, is an essential part of the water cycle. 4  All weather takes place in the atmosphere.
Energy transformation can also be explained in terms of potential energy, the stored energy of a system, which can be converted into kinetic energy, the energy of movement. For example, a roller coaster sitting at the top of a hill is said to have potential energy.
In physics, energy is the property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton. Common forms of energy include the kinetic energy of a moving object, the po