http://www.ck12.org Chapter 13. Heat
it is equal to about 4.186 J.
Definition: 1000small calories= 1 f ood calorie= 4186 J→ 1. 00 kcal= 1. 00 kC= 4186 J
- Energy can be transferred in three ways: throughconduction, convection,andradiation.
a. Conduction occurs when a temperature difference exists causing the molecules of an object to transmit energy
throughout the object.
b. Convection typically arises from the movement of gases or liquids over large distances.
c. Radiation is energy transferred by electromagnetic waves (or photons).
- The relationship between the rate of heat flow (heat conduction)∆∆Et and the temperature difference∆Tis∆∆Et =
kA∆tT. Where, the rate of heat flow ∆∆Et, is measured in Js,kis the thermal conductivity that depends upon the
properties of the object,Ais the cross-section of the object, andtis distance over which the heat is conducted
between the two temperatures∆T=T 2 −T 1. - The specific heatcof a material is the amount of energy needed to raise the temperature of one kilogram of a
particular substance, one-degree Celsius.
The change in temperature∆Tof an object depends upon the amount of massmof the object being heated, the
specific heatcof the material the object is composed of and the amount of energy∆Qtransferred to the object. It
can be experimentally shown that∆T=∆mcQ→∆Q=mc∆T