m = mass of the moving object (in kilograms)
v = velocity (in meters per second)
Energy can also be stored in chemical and nuclear substances or in the water behind a dam. In these quiescent states it is called potential energy. If the potential energy in a substance is abundant and easily released, the energy-rich substance is called a fuel.
ENERGY CONVERSION MATRIX
Figure 2 To find how one form of energy is converted into another, start at the proper column and move down until the column intersects with the desired row. The box at the intersection will give typical conversion processes and examples.
| FROM⇒ | ELECTROMAGNETIC | CHEMICAL | NUCLEAR | THERMAL | KINETIC (MECHANICAL) | ELECTRICAL | GRAVITATIONAL |
|---|---|---|---|---|---|---|---|
| TO⇓ | |||||||
| ELECTROMAGNETIC | Chemiluminescence (fireflies) | Gamma reactions (Co⁵⁸ source) A-bomb | Thermal radiation (hot iron) | Accelerating charge (cyclotron) Phosphor[2] | Electromagnetic radiation[2] (TV transmitter) Electroluminescence | Unknown | |
| CHEMICAL | Photosynthesis (plants) Photochemistry (photographic film) | Radiation catalysis (hydrazine plant) Ionization (cloud chamber) | Boiling (water/steam) Dissociation | Dissociation by radiolysis | Electrolysis (production of aluminum) Battery charging | Unknown | |
| NUCLEAR | Gamma-neutron reactions (Be⁹+γ → Be⁸+n) | Unknown | Unknown | Unknown | Unknown | Unknown | |
| THERMAL | Solar absorber (hot sidewalk) | Combustion (fire) | Fission (fuel element) Fusion | Friction (brake shoes) | Resistance-heating (electric stove) | Unknown | |
| KINETIC | Radiometer Solar cell[2] | Muscle | Radioactivity (alpha particles) A-bomb | Thermal expansion (turbines) Internal combustion (engines) | Motors Electrostriction (sonar transmitter) | Falling objects | |
| ELECTRICAL | Photoelectricity (light meter) Radio antenna Solar cell[2] | Fuel cell[2] Batteries[2] | Nuclear battery[2] | Thermoelectricity[2] Thermionics[2] Thermomagnetism[2] Ferroelectricity[2] | MHD[2][3] Conventional generator | Unknown | |
| GRAVITATIONAL | Unknown | Unknown | Unknown | Unknown | Rising objects (rockets) | Unknown |
The Energy Conversion Matrix
Forms of energy are interchangeable. When gasoline is burned in an automobile engine, potential energy is first turned into heat. A portion of this heat, say 25%, is then converted into mechanical motion. The remainder of the heat is wasted and must be removed from the engine.
A multitude of processes and devices have been found which make these transformations from one form of energy to another. Many of these are listed in the blocks in [Figure 2]. Asterisks refer to direct conversion processes, the subject matter of this booklet.