The passage below contains keywords on energy, work and power, which have been jumbled up.Can you tell which is that ?
Living things need energy. It is used for movement, oraenirstip, and reproduction. Machines need energy to work: energy is also used for essential activities like cooking, and heating or cooling homes.
While it is difficult to describe energy, its function is clear do know. There are many forms of energy, heat energy and nuclear energy. Some of these energies are named according to the way they are drsote, how they are transmitted or their source.
Energy is not the same as matter and so it is not possible to touch it like you might touch a table, for example. Rather, it is observed through changing molecular arrangements, as it is being produced, stored or transmitted. For instance, a force stretches an elastic band. This means that the molecules within the elastic band are pulled further apart. When the force is removed, the molecules return to their original positions. Work is done to stretch the band, and energy is transferred from the person to become tilpantoe energy in the band. If something, e.g. a stone in connected to the band and it is released, the ceofr generated by converting the stored energy into kinetic energy may be enough to cause serious damage. A catapult is used in this way.
Energy cannot be dactree nor reyosetdd, but it can be changed from one form to another. The amount of energy during the changed may be the same but the type or quality of energy is useful for living organisms but it is not so useful in mechanical processes. Too much heat produced by industrial production and operating equipment contributes to global mwgrain. At the same time, this means is lost an usable energy is reduced.
Energy is measured in slueoej . Food packaging displays information on the mealchic energy contained in the food. Check out suck energy values the next time you go to the supermarket. You may be interested to know that at your age, a boy needs about 12 million joules a day while a girl would have to eat 6 million joules per day to have enough energy. On the other hand, what do you think an old man or woman needs to get on with each day?
We get most of our energy from the sun. This is because billions of nuclear reactions occur at its core. The sun can be thought of as a giants nuclear rotacre . The energy it emits will be gone one day, though that will not be for many millions of years at least. It has been estimated that the mass of the sun is being converted to energy at the rate of 4 million tonnes per second!
The uses of energy are so many that, believe it or not, heat energy even helps birds and gliders to fly. Rising current of warm air called thermals lift birds, which want to glide over long distance. They go on successive columns of such air, rising and falling with the reapteuterm of the air from one another. Mechanical gliders also work on the same idea.
Other than using energy it is necessary at times to keep it from being lost. Vacnonoirest of heat is an activity that is necessary in could countries. Over the centuries, man has learned from the animal kingdom how to keep warm. A good example is the polar bear, which uses hollow hair that looks white, to transmit ttelvaloiur radiation directly into the skin, where it is converted into heat energy, a lot of air spaces between the hair to provide onualinsit and a black colored skin to increase heat prontoibas by radiation. This design is so efficient at retaining heat that darrfine radiation detectors are known not to record any heat emissions from them at all ! (what do you think happens to polar bears during summers?)
See how many word you can unravel
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