University of Wisconsin-Stevens point > CNR associated Programs > Wisconsin K-12 Energy education Program > energy Education: Concepts and also Practices > ar B: energy Transfer
​ Unit 2: Energy Rules!

Section B. Energy Transfer

Energy Transfer

The 2 ways that power can be transferred are by act work and also by heat transfer.

You are watching: The transfer of thermal energy between objects


Doing Work 

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Energy deserve to be transferred from one thing to another by law work. To do occupational requires that an agent exert a force on an object over a distance. When work-related is done, energy is moved from the certified dealer to the object, which results in a adjust in the object's activity (more specifics a adjust in the object's kinetic energy). 

An example of exactly how Doing work-related Transfers power from One object to Another

Suppose that a human (the agent) exerts a force on a wheelbarrow (the object) that is initially at rest, resulting in it to relocate over a certain distance. Recall that the work done ~ above the wheelbarrow through the person is equal to the product the the person's pressure multiplied through the street traveled through the wheelbarrow. An alert that as soon as the force is exerted top top the wheelbarrow, there's a change in that is motion. The kinetic power increases. However where go the wheelbarrow get its kinetic energy? It come from the person exerting the force, who used chemical power stored in the food they ate to relocate the wheelbarrow. In various other words, once the human did job-related on the wheelbarrow, they moved a particular amount the chemical energy to the wheelbarrow, causing it to move. As a result, the person's keep of chemical power decreases and also the wheelbarrow's kinetic energy increases.

Heat Transfer 

Heat is the deliver of energy from a warmer thing to a cooler object. Because that example, a lighted complement (higher temperature object) will certainly transfer heat to a huge pan filled v lukewarm water (lower temperature object). Note that the actual lot of thermal power each object has doesn't matter, together the pan the lukewarm water could have much more thermal power than the match. What is needed for warm transfer come take ar is a difference in temperature between 2 objects. Without this difference, no heat transfer deserve to take place.

Heat have the right to be transferred in three ways: by conduction, by convection, and also by radiation.

Conduction is the deliver of energy from one molecule to one more by direct contact. This carry occurs once molecules hit against each other, comparable to a video game of pool whereby one moving ball strikes another, leading to the 2nd to move. Conduction takes location in solids, liquids, and gases, yet works best in products that have simple molecules the are located close to every other. For example, metal is a far better conductor than lumber or plastic.

Convection is the activity of warmth by a fluid such as water or air. The liquid (liquid or gas) move from one place to another, carrying heat together with it. This activity of a mass of heated water or wait is referred to as a current.

Radiation is the move of heat by electromagnetic waves. When you stand in the sun, you room warmed through the electromagnetic waves, mostly infrared radiation (and come a lesser extent, visible light), the travels from the sun to Earth. In enhancement to the sun, light bulbs, irons, and toasters additionally transfer warm via radiation. Keep in mind that, unlike conduction or convection, warm transfer through radiation does no need any kind of matter to assist with the transfer.

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You deserve to detect proof of heat transfer. You could see the air shimmering end a radiator (convection), placed your hand top top a heat spoon that's been sitting in a hot bowl the soup (conduction), or notification that the sunlight shine feels heat on your skin (radiation). If girlfriend need evidence of thermal power or warm in your life, just feel her arm. Your body generates heat 24 hours a day! (Taken from KEEP energy Education activity Guide "Exploring Heat").