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

### Energy Transfer

The two ways that energy can be transferred room by law work and also by warm transfer.

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### Doing Work

Energy can be transferred from one object to one more by act work. To do occupational requires the an agent exert a force on an object over a distance. When occupational is done, energy is transferred from the certified dealer to the object, which outcomes in a adjust in the object's motion (more specifics a adjust in the object's kinetic energy).

### An instance of exactly how Doing work-related Transfers energy from One thing to Another

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

### Heat Transfer

Heat is the transfer of energy from a warmer object to a cooler object. For example, a lighted match (higher temperature object) will certainly transfer heat to a large pan filled v lukewarm water (lower temperature object). Keep in mind that the actual lot of thermal energy each object has actually doesn't matter, as the pan the lukewarm water could have more thermal power than the match. What is essential for warm transfer to take location is a difference in temperature between two objects. There is no this difference, no heat transfer deserve to take place.

Heat deserve to be moved in 3 ways: by conduction, by convection, and by radiation.

Conduction is the move of energy from one molecule to an additional by direct contact. This move occurs when molecules hit against each other, similar to a game of pool whereby one relocating ball strikes another, leading to the second to move. Conduction takes place in solids, liquids, and gases, however works finest in materials that have an easy molecules the are located close to each other. Because that example, steel is a far better conductor than wood or plastic.

Convection is the movement of warm by a liquid such as water or air. The liquid (liquid or gas) moves from one place to another, transferring heat along with it. This motion of a massive of heated water or waiting is dubbed a current.

Radiation is the transfer of heat by electromagnetic waves. When you was standing in the sun, you space warmed by the electromagnetic waves, mainly infrared radiation (and to a lesser extent, visible light), that travels from the sun to Earth. In addition to the sun, irradiate bulbs, irons, and toasters likewise transfer warm via radiation. Keep in mind that, uneven conduction or convection, warmth transfer by radiation does no need any matter to help 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 heat spoon that's to be sitting in a warm bowl the soup (conduction), or an alert that the sunlight shine feels heat on her skin (radiation). If friend need evidence of thermal power or heat in your life, just feel your arm. Her body generates warmth 24 hours a day! (Taken from KEEP power Education activity Guide "Exploring Heat").