Energy is neither created nor destroyed. Energy can be transformed from one form to another, but transformation between forms often results in the loss of usable energy through the production of heat.

*Energy appears in different forms and can be transformed within a system.
*Energy can be transformed within a system or transferred from one system to another (or from a system to its environment) in different ways. Thermal energy is transferred from warmer objects to cooler objects. Mechanical energy can be transferred when two objects push or pull on one another or by the propagation of waves (e.g., sound, ocean waves, seismic waves). Electromagnetic energy can be transferred when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device or by the propagation of light. Chemical energy is transferred when atoms are rearranged in a chemical reaction.
*Heat energy is usually a by-product of an energy transformation.
*Heat moves in predictable ways, normally flowing from warmer objects to cooler ones, until the objects reach the same temperature.
*Thermal energy is transferred through a material by the collisions of atoms within the material. If the material is fluid, convection currents will be setups that aid the transfer of heat. In addition, some thermal energy in all materials is transformed into infrared light energy and radiated into the environment.
*Batteries store chemical energy and transform it into electrical energy.
*Light from the sun is composed of different wavelengths of electromagnetic radiation.
*The sun is the main source of energy for biological systems on the surface of the earth.
*Plants transform light energy into chemical energy, which then can be used by other living things.
*Energy from the sun warms air and water, which creates moving currents within them. This movement drives changes on the earth's surface.
*Waves transfer energy without transferring matter.


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