A system possesses energy if it has the ability to do work.
Work shifts energy from one system to another.
We can explain this phenomenon in terms of energy and matter. Energy does work when it forces something to move. As the particles move faster, the temperature increases. Well, if there's nothing there to move, no work can be done, even if energy is available. Outer space is void of matter. Therefore, the energy from the Sun doesn't have anything to warm up.
Energy has a number of different forms, all of which measure the ability of an object or system to do work on another object or system.
An object can posses kinetic energy due to its motion. The kinetic energy is equal to the work needed to accelerate the object from rest to its stated velocity. Having gained this energy during its acceleration, the object maintains this kinetic energy unless its speed changes. The same amount of work is done by the body in decelerating from its current speed to a state of rest.
Kinetic energy is expressed in J (joules).
How to calculate the kinetic energy of a 400kg roller coaster car moving at a speed of 20 m/s:
Formula: E = 0.5 × 400 × 20² (E = 0.5 x 400 x 400)
Answer: The Kinetic Energy = 80000 Joules or 0.8 x 10^5 Joules
Picture by Allen.G / Shutterstock.com
A dramatic example of motion energy is a car crash, when the car comes to a total stop and releases all its motion energy at once in an uncontrolled instant.
It has been projected that by 2050 one third of the world's electricity may come from wind.
An object can store potential energy as the result of its position (eg a weight an en elevated position). If the object is raised then it gains potential energy. If the object is lowered, it loses potential energy.
Potential energy is expressed in J (joules).
Energy in an object due to its motion or position, or both. According to the principle of conservation of mechanical energy, the mechanical energy of an isolated system remains constant in time, as long as the system is free of friction and other non-conservative forces. In any real situation, frictional forces and other non-conservative forces are present, but in many cases their effects on the system are so small that the principle of conservation of mechanical energy can be used as a fair approximation.
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Thermal energy is possessed by an object or system due to the movement of particles within it. This movement means it is a type of kinetic energy.
Thermal energy results in something having an internal temperature, which can be measured. The faster the particles move, the higher the temperature.
Let's take a look at a simple example of thermal energy. A heated element on a stove contains thermal energy, and the more you turn up the stove, the more internal energy the stove contains. At a basic level, this thermal energy is the movement of the molecules that make up the metal of the stove's element. The faster the molecules, the more internal thermal energy they contain.
Now let's place a pot of water on top of the heated element. What happens? The stove works, right? Well, not as we would typically think of it. Here, 'work' is referring to 'the movement of something when a force is applied.' Specifically, the thermal energy of the stove causes the particles of the pot and eventually the water to move faster. The internal energy of the heated element is transferred to the pot and ultimately the water within the pot. This transfer of thermal energy from the stove to the pot and to the water is referred to as heat. It is important to keep these terms straight. In this context, heat is the term we use to refer to the transfer of thermal energy from one object or a system to another. The thermal energy is the energy possessed within the object or within the system due to movement of particles. They're different - heat and thermal energy.
You can feel the heat if you hold your hand above the stove. The heat, in turn, speeds up the molecules within the pot and the water. If you place a thermometer in the water, as the water heats up you can watch the temperature rise. Again, an increase in internal energy will result in an increase in temperature.
Hot air balloon.
Hot air balloons get their buoyancy from hot air created by a propane burner at the base of the balloon. Hot air is less dense than cold air that surrounding the balloon and so weighs less. When the cold air that is displaced weighs more than the balloon, the balloon will rise. The balloons weight is controlled by turning the burner on and off when needed.
The principle behind this lift is called Archimedes' principle, which states that any object (regardless of its shape) that is suspended in a fluid, is acted upon by an upward buoyant force equal to the weight of the fluid displaced by the object. So an object floating in water stays buoyant using the same principle as a hot air balloon.
Geothermal energy is thermal energy generated and stored in the Earth. The geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of materials (80%). The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.
Read more about geothermal energy here:
How geothermal energy works
Radiant energy includes visible light, x-rays, gamma rays and radio waves. Solar energy is an example of radiant energy. It is a form of energy that can travel through space. The sun's heat is not transmitted through any solid medium, but through a vacuum. This is possible by electromagnetic waves.
There are different kinds of electromagnetic waves and all of them have different wavelengths, properties, frequencies and power, and all interact with matter differently. The entire wave system from the lowest frequency to the highest frequency is known as the electromagnetic spectrum. The shorter the wavelength, the higher its frequency and vice versa. White light for example, is a form of radiant energy, and its frequency forms a tiny bit of the entire electromagnetic spectrum.
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When radiant energy comes into contact with matter, it changes the properties of that matter. For example, when micro-waves are set off in a microwave oven, the water molecules in the food are charged and caused to vibrate billions of times per second, generating heat, that causes the food to cook.
Solar energy is the cleanest and most abundant renewable energy source available.
The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year. In 2002, this was more energy in one hour than the world used in one year.
Electrical energy is the moving electrical charges from one point to another in a conductor. Electrical energy also can be transformed into another form of energy.
Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves. Sound is produced when a force causes an object or substance to vibrate.
Chemical reactions often involve changes in energy due to the breaking and formation of bonds.
Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic.
Due to the absorption of energy when chemical bonds are broken, and the release of energy when chemical bonds are formed, chemical reactions almost always involve a change in energy between products and reactants. By the Law of Conservation of Energy, however, we know that the total energy of a system must remain unchanged, and that often a chemical reaction will absorb or release energy in the form of heat, light, or both. The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants. This stored chemical energy, or heat content, of the system is known as its enthalpy.
Exothermic reactions release heat and light into their surroundings. For example, combustion reactions are usually exothermic. In exothermic reactions, the products have less enthalpy than the reactants, and as a result, an exothermic reaction is said to have a negative enthalpy of reaction. This means that the energy required to break the bonds in the reactants is less than the energy released when new bonds form in the products. Excess energy from the reaction is released as heat and light.
Endothermic reactions absorb heat and/or light from their surroundings. For example, decomposition reactions are usually endothermic. In endothermic reactions, the products have more enthalpy than the reactants. Thus, an endothermic reaction is said to have a positive enthalpy of reaction. This means that the energy required to break the bonds in the reactants is more than the energy released when new bonds form in the products; in other words, the reaction requires energy to proceed.
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The energy stored in a spring depends on the distance the spring is deformed (stretched or compressed) and the spring constant, which defines the amount of force required to deform a spring by a certain length (the work done on the spring). The ability to get energy out depends on the material's elasticity.
Elastic potential energy - Energy Education
Gravitational potential energy is the energy possessed by masses according to their spatial arrangement and the gravitational force that pulls them towards one another.
Since Earth is so large compared to the objects on it, it's easy to watch these objects being pulled (falling) towards the center of the planet, not the planet being pulled towards the object. The direction of Earth's gravitational pull is just called "down".
Gravitational potential energy - Energy Education
Nuclear power is the use of nuclear reactors to release nuclear energy, and thereby generate electricity. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently, the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy.
Text via Wikipedia.