SM0486
LESSON 1: TEMPERATURE AND HUMIDITY MEASUREMENT
AIPD Subcourse Number SM0486...........MECHANICAL
AND
ELECTRO-MECHANICAL
MEASUREMENT PRINCIPLES
Lesson Objective.......................Given learning objectives and text, you
should be able to answer all exercise
questions pertaining to the nature of heat
and temperature, temperature scales and
thermometers, heat sensing and measuring
instruments, and humidity with no errors.
Credit Hours...........................Two
TEXT
1.
INTRODUCTION
Your next assignment may be the calibration of a temperature measuring
instrument or the use of a temperature measuring instrument for calibration
purposes. Your job will be much easier if you have a complete understanding of the
terms and principles associated with temperature measurements.
The information
contained in this chapter concerns the nature of heat and temperature, the methods
by which heat is generated and transferred, the units used in temperature
measurements, and the principles applied in temperature measurements.
2.
THE NATURE OF HEAT AND TEMPERATURE
a. Heat is considered to be a form of energy.
The terms "thermal" and
"kinetic" are usually added as confusion factors. To make your day complete, some
authors use the terms "heat" and "temperature" as if they are the same. Let's see
if we can identify some of the terms associated with heat and temperature
measurements and establish practical definitions for these terms.
b. Heat.
Most of us use the word "heat" without bothering to consider or
determine its true meaning. We usually have a general idea of what we mean when we
use the word, but for measurements in a laboratory, you must know precisely what
the word means and the conditions and limitations under which the meaning is true.
What answer would you give if a photographer, or an artist, or a common laborer
asked the question, "What is heat?"
In your search for an answer, would you say
that heat:
Causes metals to expand?
Can be generated by rubbing two or more bodies together?
Is generated by compression?
Is an invisible weightless fluid called caloric?
Is electricity?
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