University that Wisconsin-Stevens allude > CNR connected Programs > Wisconsin K-12 Energy education and learning Program > energy Education: Concepts and Practices > ar B: energy Transfer
​ Unit 2: Energy Rules!

Section B. Energy Transfer

Energy Transfer

The two ways that energy can be transferred room by doing work and also by heat transfer.

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Doing Work 

Energy can be moved from one thing to one more by law work. To do work requires that an agent exert a force on an object over a distance. When work-related is done, power is transferred from the agent to the object, which results in a readjust in the object's motion (more special, a change in the object's kinetic energy). 

An instance of how Doing occupational Transfers energy from One object to Another

Suppose that a human (the agent) exerts a force on a wheelbarrow (the object) that is at first at rest, bring about it to relocate over a certain distance. Recall the the work-related done top top the wheelbarrow through the person is same to the product of the person's pressure multiplied by the street traveled by the wheelbarrow. An alert that once the pressure is exerted ~ above the wheelbarrow, there's a readjust in the motion. That kinetic energy increases. Yet where go the wheelbarrow obtain its kinetic energy? It come from the person exerting the force, who supplied chemical power stored in the food they ate to relocate the wheelbarrow. In other words, when the human did occupational on the wheelbarrow, they transferred a specific amount of chemical energy to the wheelbarrow, resulting in it to move. Together a result, the person's store of chemical power decreases and the wheelbarrow's kinetic power increases.

Heat Transfer 

Heat is the transport of power from a warmer thing to a cooler object. For example, a lighted complement (higher temperature object) will certainly transfer warmth to a large pan filled v lukewarm water (lower temperature object). Note that the actual amount of thermal energy each object has doesn't matter, as the pan that lukewarm water might have more thermal energy than the match. What is essential for heat transfer come take ar is a difference in temperature between two objects. There is no this difference, no warmth transfer deserve to take place.

Heat deserve to be moved in three ways: by conduction, by convection, and also by radiation.

Conduction is the deliver of energy from one molecule to another by direct contact. This transport occurs as soon as molecules hit against each other, comparable to a game of pool where one relocating ball strikes another, resulting in the 2nd to move. Conduction takes location in solids, liquids, and gases, however works best in products that have simple molecules the are located close to each other. For example, metal is a better conductor than timber or plastic.

Convection is the activity of heat by a fluid such as water or air. The liquid (liquid or gas) move from one place to another, transferring heat in addition to it. This movement of a mass of boil water or waiting is referred to as a current.

Radiation is the move of heat by electromagnetic waves. When you was standing in the sun, you are warmed through the electromagnetic waves, greatly infrared radiation (and come a lesser extent, visible light), that travels indigenous the sun to Earth. In enhancement to the sun, irradiate bulbs, irons, and also toasters additionally transfer heat via radiation. Note that, uneven conduction or convection, warm transfer through radiation does not need any type of matter to aid with the transfer.

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You deserve to detect proof of warm transfer. You could see the air shimmering over a radiator (convection), placed your hand ~ above a warmth spoon that's been sitting in a warm bowl that soup (conduction), or notice that the sun shine feels warmth on her skin (radiation). If friend need proof of thermal power or heat in your life, just feel your arm. Your body generates warm 24 hrs a day! (Taken from KEEP energy Education task Guide \"Exploring Heat\").