Heat
BUCUN BENGKEL : Heat is a form of energy.
It has the relationship to the atom. All substances are made up of tiny atoms,
which combine to make molecules. If all heat is removed from a substance (absolute
zero), all molecular motion stops.
* Experiment in heating :
The unit of heat is
the British thermal unit (BTU). A Btu is the amount of heat required to
raise the temperature of one pound of water by one degree Fahrenheit. In SI
metric, the unit of heat is the joule (J). A joule is a very small unit of
heat. The amount of heat required to raise the temperature of 1 Kg of water by
1°C is equal to 4,187 KJ.
* Experiment in heating :
1. Raising temperature of
1 pound of water from 63°F to 64° F requires one British thermal unit (1 Btu) of heat.
Example 1 :
Find the amount of
heat required to raise the temperature of 42 pound of water 45°F to 90°F.
Solution :
Btu = water in pound x
temperature change in °F
Btu = 42 lb x (90-45) °F
Btu = 1890 Btu
Example 2 :
In SI Metric Units :
Calculation the amount
of heat required to raise the temperature of 5 Kg water from 5°C to 32°C.
Solution :
KJ = 4,187 x mass in
Kilograms x temperature change in °C
KJ = 4,187 x 5 Kg x (32-5)
°C
KJ = 565 KJ
* SI metric
(le Systeme International d’Unites) : Metric system of measurement adopted by
most technical industries throughout the world
* Heat transfer by conduction
Source : Panasonic
Heat Flow
Heat always flow from
a warmer to a cooler substance. The faster moving atoms give up some of their
energy to slower moving atoms. Therefore, each fast atom slow down a little and
the slower one moves a little faster.
* Heat transfer by conduction
Source : Panasonic
