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Share Flipboard Email. Andrew Zimmerman Jones. Math and Physics Expert. Andrew Zimmerman Jones is a science writer, educator, and researcher. He is the co-author of "String Theory for Dummies. This technology still faces challenges in terms of economic and environmental impacts. Try This Out - Solar Still. Educational Programs Tell Me About. Hours and Location Open 10 a. Physics of Energy. How it works Energy comes in many different forms.
Energy is the ability to do work or cause change. It is different from a force. A force is the thing that causes the change, while energy can be thought of as the impetus behind the force. It takes energy in order to apply a force, and applying a force to an object often transfers energy to it. Other units include calories, kilocalories and kilowatt-hours. Potential energy is stored energy while kinetic energy is the energy of motion.
Scientists usually differentiate between macroscopic and microscopic versions of these energy types. But objects can also have a different type of potential energy stored in the bonds between molecules and between nucleons in an atomic nucleus. Mechanical kinetic energy is the energy due to the motion of a macroscopic object. But inside any object, the molecules themselves have their own kinetic energies of a different type.
This is not the same as the object's total energy, which would be the sum of all forms of its energy, including thermal, chemical and so on. When you measure temperature, you are measuring the average amount of this type of energy. Mechanical kinetic energy differs from potential energy in that it is associated with motion, and it comes in just one variety.
That is:. When an object that has potential energy is released and allowed to move freely, it will begin to accelerate. As a result, its kinetic energy increases. At the same time, the potential energy decreases. In the last section, the equation for mechanical kinetic energy was introduced.
There are also formulas for different types of potential energies as well as equations that describe the relationship between energy and other physical quantities. The potential energy stored in a spring is given by:. The temperature of something is a direct measurement of how fast the atoms inside it are moving. In a hot cup of coffee, the water molecules are racing around at a fast clip, slowing down as the cup cools. Throw an iron bar into the fire and its atoms start moving faster too, although in this case the atoms are bound in position, and so the movement is the form of a jiggling vibration.
Sometimes an object is pulled or pushed in a particular direction, but its movement is stopped by some other force. In this case, the object is said to have potential energy — the potential to move. A glass sitting on a table is being pulled down by the force of gravity. But any movement is being stopped by a much stronger force — the electrical repulsion of the atoms in the table.
Give the glass a nudge off the table, though, and it falls.
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