You are about to become acquainted with the
fascinating world of PHYSICS. You will learn
about the various natural and physical laws and
phenomena. Physics is concerned with those
aspects of nature which can be understood
in a fundamental way in terms of elementary
principles and laws. The forces of physics and the
laws of nature are at work in every piece of
machinery and equipment. It is by these forces
and laws that the machinery and equipment
In the following paragraphs you will learn
about matter, magnetism, electricity, motion,
properties of mass, temperature, pressure, various
laws and principles of physics dealing with
motion, gases, hydraulics and pneumatics, and
basic information on metals. After studying this
chapter, you will have the fundamental, basic
knowledge to understand what electrical and
mechanical devices are all about and how they
If western science has roots, they probably lie
in the rubble that was once ancient Greece.
Except for the Greeks, ancient people had little
interest in the structure of materials. They
accepted a solid as being just thata continuous,
uninterrupted substance. One Greek school of
thought believed that if a piece of matter, such
as copper, were subdivided, it could be subdivided
indefinitely and still only that material would be
found. Others reasoned that a limit exists to the
number of subdivisions that could be made and
have the material still retain its original
characteristics. They held fast to the idea that
all substances are built upon a basic particle.
Experiments have revealed that, indeed, several
basic particles, or building blocks, are within all
Matter cannot be created nor destroyed. This
law holds within the experimental error of the
most precise chemical reactions. This theory of
the conservation of energy will be discussed later
in this chapter. Matter is defined as anything that
occupies space and has weight; that is, the weight
and dimensions of matter that can be measured.
Examples of matter are air, water, clothing, and
even our own bodies. So, we can say matter is
found in any one of three states: GASEOUS,
LIQUID, and SOLID.
In the following paragraphs we will describe
how substances are classified as elements and
compounds and how they are made up of
molecules and atoms. We will then learn about
protons, electrons, and the physics of electricity.
ELEMENTS AND COMPOUNDS
An element is a substance that cannot be
reduced to a simpler substance by chemical means.
Examples of elements with which you are in every
day contact are iron, gold, silver, copper, and
oxygen. Over 100 known elements are in existence.
All the different substances we know about are
composed of one or more of these elements.
When two or more elements are chemically
combined, the resulting substance is called a
COMPOUND. A compound is a chemical
combination of elements that can be separated
by chemical means.
Examples of common
compounds are water, which consists of hydrogen
and oxygen, and table salt, which consists of
sodium and chlorine. A MIXTURE, on the other
hand, is a combination of elements and
compounds, not chemically combined, that can
be separated by physical means. Examples of
mixtures are air, which is made up of nitrogen,
oxygen, carbon dioxide, and small amounts of
rare gases, and sea water, which consists chiefly
of salt and water.
A MOLECULE is a chemical combination of
two or more atoms, (atoms are described in the