Energy
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In physics, energy is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. 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 unit of measurement for energy in the International System of Units (SI) is the joule (J).
A plasma globe, using electrical energy to create plasma, light, heat, movement and a faint sound
In a typical lightning strike, 500 megajoules of electric potential energy is converted into the same amount of energy in other forms, mostly light energy, sound energy and thermal energy.
Thermal energy is energy of microscopic constituents of matter, which may include both kinetic and potential energy.
Thomas Young, the first person to use the term "energy" in the modern sense
Kinetic energy
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In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion.
Image: Emilie Chatelet portrait by Latour