About Energy

Energy cannot be created nor destroyed, but can be changed from one form into another. Energy can be divided into two groups - action energy and potential energy. Potential energy is stored energy, while action energy refers to energy that can be seen doing things. An energy chain is a sequence of energy changes. In the case of a Chinese gong kinetic energy is converted into sound energy, while when you speak into a telephone sound energy is converted into electrical energy. A diesel locomotive converts chemical potential energy into kinetic energy. When Tatiana Gregorieva - Olympic pole vaulter - performs the pole vault, she converts her kinetic energy into the pole's elastic potential energy, which is then converted into gravitational potential energy as she clears the bar. Energy is measured in a unit called the joule, which is quite a small unit. A larger unit is the megajoule which is a million times larger. An older unit is the calorie which is equal to 4.2 joules, and is the amount of energy required to heat a gram od water by one degree Celsius. The energy content of a food can be found by burning it and using the heat to heat water. The temperature increase is measured. All energy on the Earth can be traced back to the Sun. Fossil fuels were formed from the burial of animal and plant remains. Coal, oil and natural gas were produced this way. Photosynthesis is the name given to the process where plants use the light energy and convert it to chemical potential energy, and then store it as starch. The efficiency of a device is calculated by dividing the useful energy by the input energy and then multiplying it by 100 (a number).