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Conservation of Energy - Coggle Diagram
Conservation of Energy
Energy Stores
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Gravitational Potential: The potential energy stored in an object that is held above the surface of a planet.
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Elastic: The potential energy stored by an object as it experiences elastic deformation. It is found in objects that are impermanently stretched or compressed
Thermal: Energy produced when an object is heated and its molecules vibrate and collide with each other.
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Chemical: The potential of a chemical substance to undergo a reaction to produce energy. It is found in food, fuels, or batteries.
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Useful and Wasted Energy
A percentage of the energy that is input into a machine is outputted in a useful way. For example, the movement of the blades of a fan is useful kinetic energy. However, a percentage of the energy that is input into a machine is also outputted in a wasteful way. For example, the sound a fan produces is energy wasted through radiation
Useful and wasted energy is shown in a diagram called the Sankey diagram. A machine that uses 100J and outputs 75J of useful energy would be shown in a diagram like this
Heat Transfers
Conduction: Conduction is heat transfer through the contact of molecules and happens when a heat source causes particles to vibrate and as they vibrate they transfer energy through collision to the particles around them which spreads heat around. If the heat source was removed, the particles would eventually stop vibrating as fast, therefore losing their energy, and begin to cool down. Conduction is most effective in solids.
Convection: Convection is heat transfer through density differences. It happens when a substance is heated by a heat source and rises due to the energy it gains and the fact that its density has been reduced by the heat making it lighter and allowing it to float upwards. Once it rises high enough, it begins to cool down and sink due to the energy it has lost, and the density is has gained. Once it sinks, it is once again heated if the heat source is still present and the cycle begins again. Convection is most effective in liquids and gases.
Radiation: Radiation is heat transfer by wave motion and occurs when heat is emitted from a heat source in waves of energy (called electromagnetic waves). No material is required and radiation can happen in empty space as it does not require particles. This is how energy travels from the sun to the Earth. Radiation can also travel easily through gases and some solids and liquids such as glass and water.