Heat refers to energy transferred due to a difference in temperature.

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Celsius-to-Fahrenheit: F = 1.8C + 32

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Presentation transcript:

Heat refers to energy transferred due to a difference in temperature. QUESTION: In which of the following is the observed temperature change due to heat A. rubbing two hands together B. hitting a nail with a hammer C. Placing pot of cold water on a hot stove Heat refers to energy transferred due to a difference in temperature. Energy transferred in any other way is considered as work. In which of the following is the observed temperature change due to heat A. rubbing two hands together B. hitting a nail with a hammer C. Placing pot of cold water on a hot stove PAUSE CLICK Heat refers to energy transferred due to a difference in temperature. HGIHLIGHT “difference in temperature” Energy transferred in any other way is considered as work. HIGHLIGHT difference in temperature Let’s examine the choices given here. For choice A…. When we rub two hands together, we will observe a temperature increase. But the temperature increase in both hands is not due to putting any one of them in contact with a hotter object. Therefore, the temperature increase here cannot be attributed to heat flow. CALLOUT “work” pointing to choice A How about choice B?… Hitting a nail with a hammer will result in an increase in the temperature of the nail and the head of the hammer Again, this does not deal with two systems at that are initially at different temperatures. CALLOUT “work” pointing to choice B Choice C is obviously right… HIGHLIGHT Choice C. The pot of water and the stove are at different temperatures. We would expect the pot of cold water to warm up. And we attribute the temperature increase to heat flow. CLICK PAUSE END RECORDING

Video ID: 8-1-1 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Assisted by Johuan Gasery In partial fulfillment of the requirements for CHEM 481, Fall 2008.