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Matter, Energy, and Electricity
Learning objectives are stated at the beginning each chapter.
These learning objectives serve as a preview the information you are expected to learn in the chapter. The
comprehensive check questions are based on the objectives. By successfully completing the NRTC, you indicate that
you have met the objectives and have learned the information. The learning objectives are listed below.
Upon completing this chapter, you will be able to:
1. State the meanings and the relationship between
matter, element, nucleus, compound, molecule, mixture, atom, electron, proton, neutron, energy, valence, valence
shell, and ion.
2. State the meanings and the relationship between kinetic energy, potential energy,
photons, electron orbits, energy levels, and shells and subshells.
3. State, in terms valence, the
differences between a conductor, an insulator, and a semiconductor, and list some materials which make the best
conductors and insulators.
4. State the definition static electricity and explain how static electricity
5. State the meanings retentivity, reluctance, permeability, ferromagnetism, natural magnet,
and artificial magnet as used to describe magnetic materials.
6. State the Weber and domain theories
magnetism and list six characteristics magnetic lines force (magnetic flux), including their relation to magnetic
induction, shielding, shape, and
7. State, using the water analogy, how a difference potential (a voltage or an electromotive force) can
exist. Convert volts to microvolts, to millivolts, and to kilovolts.
8. List six methods for producing a
voltage (EMF) and state the operating principles and the uses for each method.
9. State the meanings
electron current, random drift, directed drift, and ampere, and indicate the direction that an electric current
10. State the relationship current to voltage and convert amperes to milliamperes and microamperes.
11. State the definitions and the terms and symbols for resistance and conductance, and how the temperature,
contents, length and cross-sectional area a conductor affect its resistance and conductance values.
List the physical and operating characteristics and the symbols, ratings, and uses for various types resistors;
use the color code to identify resistor values.
The origin the modern technical and electronic Navy stretches
back to the beginning naval history, when the first navies were no more than small fleets wooden ships, using
wind-filled sails and manned oars. The need for technicians then was restricted to a navigator and semiskilled
seamen who could handle the sails.
As time passed, larger ships that carried more sail were built. These
ships, encouraging exploration and commerce, helped to establish world trade routes. Soon strong navies were
needed to guard these sea lanes. Countries established their own navies to protect their citizens, commercial
ships, and shipping lanes against pirates and warring nations. With the addition mounted armament, gunners joined
the ship's company skilled or semiskilled technicians.
The advent the steam engine signaled the rise an
energy source more practical than either wind and sails or manpower. With this technological advancement, the need
for competent operators and technicians increased.
However, the big call for operators and technicians in the U.S. Navy came in the early part the 20th century,
when power sources, means communication, modes detection, and armaments moved with amazing rapidity toward
involved technical development. Electric motors and generators by then had become the most widely used sources
power. Telephone systems were well established on board ship, and radio was being used more and more to relay
messages from ship to ship and from ship to shore. Listening devices were employed to detect submarines. Complex
optical systems were used to aim large naval rifles. Mines and torpedoes became highly developed, effective
weapons, and airplanes joined the Navy team.
During the years after World War I, the Navy became more
electricity and electronic minded. It was recognized that a better system communications was needed aboard each
ship, and between the ships, planes, submarines, and shore installations; and that weaponry advances were needed
to keep pace with worldwide developments in that field. This growing technology carried with it the awareness that
an equally skilled force technicians was needed for maintenance and service duties.
World War II proved
that all the expense providing equipment for the fleet and training personnel to handle that equipment paid great
dividends. The U. S. Navy had the modern equipment and highly trained personnel needed to defeat the powerful
fleets the enemy.
Today there is scarcely anyone on board a Navy ship who does not use electrical or
electronic equipment. This equipment is needed in systems electric lighting and power, intercommunications, radio,
radar, sonar, loran, remote metering, weapon aiming, and certain types mines and torpedoes. The Navy needs trained
operators and technicians in this challenging field electronics and electricity. It is to achieve this end that
this module, and others like it, are published.
MATTER, ENERGY, AND ELECTRICITY
If there are roots to western science, they no doubt lie under the rubble that was once ancient Greece. With
the exception the Greeks, ancient people had little interest in the structure materials. They accepted a solid as
being just that a continuous, uninterrupted substance. One Greek school thought believed that if a piece matter,
such as copper, were subdivided, it could be done indefinitely and still only that material would be found. Others
reasoned that there must be a limit to the number subdivisions that could be made and have the material still
retain its original characteristics. They held
fast to the idea that there must be a basic particle upon which
all substances are built. Recent experiments have revealed that there are, indeed, several basic particles, or
building blocks within all substances.
The following paragraphs explain how substances are classified as elements and compounds, and are made
up molecules and atoms. This, then, will be a learning experience about protons, electrons, valence, energy
levels, and the physics electricity.
Matter is defined as anything that
occupies space and has weight; that is, the weight and dimensions matter can be measured. Examples matter are air,
water, automobiles, clothing, and even our own bodies. Thus, we can say that matter may be found in any one three
states: SOLID, LIQUID, and GASEOUS.
ELEMENTS AND COMPOUNDS
An ELEMENT is a
substance which cannot be reduced to a simpler substance by chemical means. Examples elements with which you are
in everyday contact are iron, gold, silver, copper, and oxygen. There are now over 100 known elements. All the
different substances we know about are composed one or more these elements.
When two or more elements are
chemically combined, the resulting substance is called a COMPOUND. A compound is a chemical combination elements
which can be separated by chemical but not by physical means. Examples common compounds are water which consists
hydrogen and oxygen, and table salt, which consists sodium and chlorine. A MIXTURE, on the other hand, is a
combination elements and compounds, not chemically combined, that can be separated by physical means. Examples
mixtures are air, which is made up nitrogen, oxygen, carbon dioxide, and small amounts several rare gases, and sea
water, which consists chiefly salt and water.
Q1. What is matter, and in what three states is it found?
Q2. What is an element?
Q3. What is a compound?
Q4. What is the difference between a
compound and a mixture?
A MOLECULE is a chemical combination two or more atoms, (atoms are described in the next paragraph). In a
compound the molecule is the smallest particle that has all the characteristics the compound.
water, for example. Water is matter, since it occupies space and has weight. Depending on the temperature, it may
exist as a liquid (water), a solid (ice), or a gas (steam). Regardless the temperature, it will still have the
same composition. If we start with a quantity water, divide this and pour out one half, and continue this process
a sufficient number times, we will eventually end up with a quantity water which cannot be further divided without
ceasing to be water. This quantity is called a molecule water. If this molecule water divided, instead two parts
water, there will be one part oxygen and two parts hydrogen (H 2 O).
Molecules are made up smaller particles called ATOMS. An atom is the smallest particle an element that retains the
characteristics that element. The atoms one element, however, differ from
the atoms all other elements. Since there are over 100 known elements, there must be over 100
different atoms, or a different atom for each element. Just as thousands words can be made by combining the proper
letters the alphabet, so thousands different materials can be made by chemically combining the proper atoms.
Any particle that is a chemical combination two or more atoms is called a molecule. The oxygen molecule consists
two atoms oxygen, and the hydrogen molecule consists two atoms hydrogen. Sugar, on the other hand, is a compound
composed atoms carbon, hydrogen, and oxygen. These atoms are combined into sugar molecules. Since the sugar
molecules can be broken down by chemical means into smaller and simpler units, we cannot have sugar atoms.
The atoms each element are made up electrons, protons, and, in most cases, neutrons, which are collectively called
subatomic particles. Furthermore, the electrons, protons, and neutrons one element are identical to those any
other element. The reason that there are different kinds elements is that the number and the arrangement electrons
and protons within the atom are different for the different elements.
The electron is considered to be a
small negative charge electricity. The proton has a positive charge electricity equal and opposite to the charge
the electron. Scientists have measured the mass and size the electron and proton, and they know how much charge
each possesses. The electron and proton each have the same quantity charge, although the mass the proton is
approximately 1837 times that the electron. In some atoms there exists a neutral particle called a neutron. The
neutron has a mass approximately equal to that a proton, but it has no electrical charge. According to a popular
theory, the electrons, protons, and neutrons the atoms are thought to be arranged in a manner similar to a
miniature solar system. The protons and neutrons form a heavy nucleus with a positive charge, around which the
very light electrons revolve.
Figure 1-1 shows one hydrogen and one helium atom. Each has a relatively
simple structure. The hydrogen atom has only one proton in the nucleus with one electron rotating about it. The
helium atom is a little more complex. It has a nucleus made up two protons and two neutrons, with two electrons
rotating about the nucleus. Elements are classified numerically according to the complexity their atoms. The
atomic number an atom is determined by the number protons in its nucleus.
Figure 1-1. - Structures simple atoms.
In a neutral state, an atom contains an equal number protons and electrons. Therefore, an atom
hydrogen - which contains one proton and one electron - has an atomic number 1; and helium, with
two protons and two electrons, has an atomic number 2. The complexity atomic structure increases with
the number protons and electrons.
Q5. What is a molecule?
Q6. What are the three types
subatomic particles, and what are their charges?
Since an electron in
an atom has both mass and motion, it contains two types energy. By virtue its motion the electron contains KINETIC
ENERGY. Due to its position it also contains POTENTIAL ENERGY. The total energy contained by an electron (kinetic
plus potential) is the factor which determines the radius the electron orbit. In order for an electron to remain
in this orbit, it must neither GAIN nor LOSE energy.
It is well known that light is a form energy, but the
physical form in which this energy exists is not known.
One accepted theory proposes the existence light as
tiny packets energy called PHOTONS. Photons can contain various quantities energy. The amount depends upon the
color the light involved. Should a photon sufficient energy collide with an orbital electron, the electron will
absorb the photon's energy, as shown in figure 1-2. The electron, which now has a greater than normal amount
energy, will jump to a new orbit farther from the nucleus. The first new orbit to which the electron can jump has
a radius four times as large as the radius the original orbit. Had the electron received a greater amount energy,
the next possible orbit to which it could jump would have a radius nine times the original. Thus, each orbit may
be considered to represent one a large number energy levels that the electron may attain. It must be emphasized
that the electron cannot jump to just any orbit. The electron will remain in its lowest orbit until a sufficient
amount energy is available, at which time the electron will accept the energy and jump to one a series permissible
orbits. An electron cannot exist in the space between energy levels. This indicates that the electron will not
accept a photon energy unless it contains enough energy to elevate itself to one the higher energy levels. Heat
energy and collisions with other particles can also cause the electron to jump orbits.
Figure 1-2. - Excitation by a photon.
Once the electron has been elevated to an energy level higher than the lowest possible energy level,
the atom is said to be in an excited state. The electron will not remain in this excited condition for more than a
fraction a second before it will radiate the excess energy and return to a lower energy orbit. To illustrate this
principle, assume that a normal electron has just received a photon energy sufficient to raise it from the first
to the third energy level. In a short period time the electron may jump back to the first level emitting a new
photon identical to the one it received.
A second alternative would be for the electron to return to the
lower level in two jumps; from the third to the second, and then from the second to the first. In this case the
electron would emit two photons, one for each jump. Each these photons would have less energy than the original
photon which excited the electron.
This principle is used in the fluorescent light where ultraviolet light photons, which are not visible to the
human eye, bombard a phosphor coating on the inside a glass tube. The phosphor electrons, in returning to their
normal orbits, emit photons light that are visible. By using the proper chemicals for the phosphor coating, any
color light may be obtained, including white. This same principle is also used in lighting up the screen a
television picture tube.
The basic principles just developed apply equally well to the atoms more complex
elements. In atoms containing two or more electrons, the electrons interact with each other and the exact path any
one electron is very difficult to predict. However, each electron lies in a specific energy band and the orbits
will be considered as an average the electron's position.
Q7. What is energy motion called?
How is invisible light changed to visible light in a fluorescent light?
Shells and Subshells
The difference between the atoms, insofar as their chemical activity and stability are concerned, is dependent
upon the number and position the electrons included within the atom. How are these electrons positioned within the
atom? In general, the electrons reside in groups orbits called shells. These shells are elliptically shaped and
are assumed to be located at fixed intervals. Thus, the shells are arranged in steps that correspond to fixed
energy levels. The shells, and the number electrons required to fill them, may be predicted by the employment
Pauli's exclusion principle. Simply stated, this principle specifies that each shell will contain a maximum
2n2electrons, where n corresponds to the shell number starting with the one closest to the nucleus. By this
principle, the second shell, for example, would contain 2(2) 2 or 8 electrons when full.
In addition to
being numbered, the shells are also given letter designations, as pictured in figure 1-3. Starting with the shell
closest to the nucleus and progressing outward, the shells are labeled K, L, M, N, O, P, and Q, respectively. The
shells are considered to be full, or complete, when they contain the following quantities electrons: two in the K
shell, eight in the L shell, 18 in the M shell, and so on, in accordance with the exclusion principle. Each these
shells is a major shell and can be divided into subshells, which there are four, labeled s, p, d, and f. Like the
major shells, the subshells are also limited as to the number electrons which they can contain. Thus, the "s"
subshell is complete when it contains two electrons, the "p" subshell when it contains 10, and the "f" subshell
when it contains 14 electrons.
Figure 1-3. - Shell designation.
Inasmuch as the K shell can contain no more than two electrons, it must have only one subshell, the s
subshell. The M shell is composed three subshells: s, p, and d. If the electrons in the s, p, and d subshells are
added, their total is found to be 18, the exact number required to fill the M shell. Notice the electron
configuration for copper illustrated in figure 1-4. The copper atom contains 29 electrons, which completely fill
the first three shells and subshells, leaving one electron in the "s" subshell the N shell.
Figure 1-4. - Copper atom.
The number electrons in the outermost shell determines the valence an
atom. For this reason, the outer shell an atom is called the VALENCE SHELL; and the electrons contained in this
shell are called VALENCE ELECTRONS. The valence an atom determines its ability to gain or lose an electron, which
in turn determines the chemical and electrical properties the atom. An atom that is
lacking only one or two electrons from its outer shell will easily gain electrons to complete its
shell, but a large amount energy is required to free any its electrons. An atom having a relatively small number
electrons in its outer shell in comparison to the number electrons required to fill the shell will easily lose
these valence electrons. The valence shell always refers to the outermost shell.
Q9. What determines the
valence an atom?
When the atom loses electrons or gains electrons in
this process electron exchange, it is said to be IONIZED. For ionization to take place, there must be a transfer
energy which results in a change in the internal energy the atom. An atom having more than its normal amount
electrons acquires a negative charge, and is called a NEGATIVE ION. The atom that gives up some its normal
electrons is left with less negative charges than positive charges and is called a POSITIVE ION. Thus, ionization
is the process by which an atom loses or gains electrons.
Q1O. What is an ion?
SEMICONDUCTORS, AND INSULATORS
In this study electricity and electronics, the association matter and electricity is important. Since every
electronic device is constructed parts made from ordinary matter, the effects electricity on matter must be well
understood. As a means accomplishing this, all elements which matter is made may be placed into one three
categories: CONDUCTORS, SEMICONDUCTORS, and INSULATORS, depending on their ability to conduct an electric current.
CONDUCTORS are elements which conduct electricity very readily, INSULATORS have an extremely high resistance to
the flow electricity. All matter between these two extremes may be called SEMICONDUCTORS.
theory states that all matter is composed atoms and the atoms are composed smaller particles called protons,
electrons, and neutrons. The electrons orbit the nucleus which contains the protons and neutrons. It is the
valence electrons that we are most concerned with in electricity. These are the electrons which are easiest to
break loose from their parent atom. Normally, conductors have three or less valence electrons; insulators have
five or more valence electrons; and semiconductors usually have four valence electrons.
conductivity matter is dependent upon the atomic structure the material from which the conductor is made. In any
solid material, such as copper, the atoms which make up the molecular structure are bound firmly together. At room
temperature, copper will contain a considerable amount heat energy. Since heat energy is one method removing
electrons from their orbits, copper will contain many free electrons that can move from atom to atom. When not
under the influence an external force, these electrons move in a haphazard manner within the conductor. This
movement is equal in all directions so that electrons are not lost or gained by any part the conductor. When
controlled by an external force, the electrons move generally in the same direction. The effect this movement is
felt almost instantly from one end the conductor to the other. This electron movement is called an ELECTRIC
Some metals are better conductors electricity than others. Silver, copper, gold, and aluminum are materials
with many free electrons and make good conductors. Silver is the best conductor, followed by copper, gold, and
aluminum. Copper is used more ten than silver because cost. Aluminum is used where weight is a major
consideration, such as in high-tension power lines, with long spans between supports. Gold is used where oxidation
or corrosion is a consideration and a good conductivity is
required. The ability a conductor to handle current also depends upon its physical dimensions.
Conductors are usually found in the form wire, but may be in the form bars, tubes, or sheets.
have few free electrons. These materials are called INSULATORS. Some examples these materials are rubber, plastic,
enamel, glass, dry wood, and mica. Just as there is no perfect conductor, neither is there a perfect insulator.
Some materials are neither good conductors nor good insulators, since their electrical characteristics fall
between those conductors and insulators. These in-between materials are classified as SEMICONDUCTORS. Germanium
and silicon are two common semiconductors used in solid-state devices.
Q11. What determines whether a
substance is a conductor or an insulator?
(electricity at rest) is a subject with which most persons entering the field electricity and electronics are
somewhat familiar. For example, the way a person's hair stands on end after a vigorous rubbing is an effect
electrostatics. While pursuing the study electrostatics, you will gain a better understanding this common
occurrence. even greater significance, the study electrostatics will provide you with the opportunity to gain
important background knowledge and to develop concepts which are essential to the understanding electricity and
Interest in the subject static electricity can be traced back to the Greeks. Thales Miletus, a
Greek philosopher and mathematician, discovered that when an amber rod is rubbed with fur, the rod has the amazing
characteristic attracting some very light objects such as bits paper and shavings wood.
About 1600, William
Gilbert, an English scientist, made a study other substances which had been found to possess qualities attraction
similar to amber. Among these were glass, when rubbed with silk, and ebonite, when rubbed with fur. Gilbert
classified all the substances which possessed properties similar to those amber as electrics, a word Greek origin
Because Gilbert's work with electrics, a substance such as amber or glass when given a
vigorous rubbing was recognized as being ELECTRIFIED, or CHARGED with electricity.
In the year 1733,
Charles Dufay, a French scientist, made an important discovery about electrification. He found that when a glass
was rubbed with fur, both the glass rod and the fur became electrified. This realization came when he
systematically placed the glass rod and the fur near other electrified substances and found that certain
substances which were attracted to the glass rod were repelled by the fur, and vice versa. From experiments such
as this, he concluded that there must be two exactly opposite kinds electricity.
American statesman, inventor, and philosopher, is credited with first using the terms POSITIVE and NEGATIVE to
describe the two opposite kinds electricity. The charge produced on a glass rod when it is rubbed with silk,
Franklin labeled positive. He attached the term negative to the charge produced on the silk. Those bodies which
were not electrified or charged, he called NEUTRAL.
In a natural, or neutral state, each atom in a body matter will have
the proper number electrons in orbit around it. Consequently, the whole body matter composed the neutral atoms
will also be
electrically neutral. In this state, it is said to have a "zero charge." Electrons will neither leave
nor enter the neutrally charged body should it come in contact with other neutral bodies. If, however, any number
electrons are removed from the atoms a body matter, there will remain more protons than electrons and the whole
body matter will become ELECTRICALLY POSITIVE. Should the positively charged body come in contact with another
body having a normal charge, or having a NEGATIVE (too many electrons) charge, an electric current will flow
between them. Electrons will leave the more negative body and enter the positive body. This electron flow will
continue until both bodies have equal charges. When two bodies matter have unequal charges and are near one
another, an electric force is exerted between them because their unequal charges. However, since they are not in
contact, their charges cannot equalize. The existence such an electric force, where current cannot flow, is
referred to as static electricity. ("Static" in this instance means "not moving.") It is also referred to as an
One the easiest ways to create a static charge is by friction. When two pieces matter
are rubbed together, electrons can be "wiped f" one material onto the other. If the materials used are good
conductors, it is quite difficult to obtain a detectable charge on either, since equalizing currents can flow
easily between the conducting materials. These currents equalize the charges almost as fast as they are created. A
static charge is more easily created between nonconducting materials. When a hard rubber rod is rubbed with fur,
the rod will accumulate electrons given up by the fur, as shown in figure 1-5. Since both materials are poor
conductors, very little equalizing current can flow, and an electrostatic charge builds up. When the charge
becomes great enough, current will flow regardless the poor conductivity the materials. These currents will cause
visible sparks and produce a crackling sound.
Figure 1-5. - Producing static electricity by friction.
Q12. How is a negative charge created in a neutral body?
Q13. How are static charges created?
When in a natural, or neutral state, an atom has an equal number
electrons and protons. Because this balance, the net negative charge the electrons in orbit is exactly balanced by
the net positive charge the protons in the nucleus, making the atom electrically neutral.
NEETS Table of Contents
- Introduction to Matter, Energy,
and Direct Current
- Introduction to Alternating Current and Transformers
- Introduction to Circuit Protection,
Control, and Measurement
- Introduction to Electrical Conductors, Wiring
Techniques, and Schematic Reading
- Introduction to Generators and Motors
- Introduction to Electronic Emission, Tubes,
and Power Supplies
- Introduction to Solid-State Devices and
- Introduction to Amplifiers
- Introduction to Wave-Generation and Wave-Shaping
- Introduction to Wave Propagation, Transmission
Lines, and Antennas
- Microwave Principles
- Modulation Principles
- Introduction to Number Systems and Logic Circuits
- Introduction to Microelectronics
- Principles of Synchros, Servos, and Gyros
- Introduction to Test Equipment
- Radio-Frequency Communications Principles
- Radar Principles
- The Technician's Handbook, Master Glossary
- Test Methods and Practices
- Introduction to Digital Computers
- Magnetic Recording
- Introduction to Fiber Optics