LET'S START TO BUILD...
We begin by learning the FUNdamental principle of an electromagnet and related STEM knowledge.
The Fundamental Principle of an Electromagnet
An electric current flowing through a conductor, like a wire, creates a magnetic field around it.
Another way to say this is, MOVING ELECTRIC CHARGES CREATE MAGNETIC FIELDS.
STEM Knowledge
Here are 7 related topics with brief definitions (We expand on these below).
1. The ATOM
The basic unit of matter that makes up everything around us, including us 🙂
2. Electric Charge
There are two kinds of Electric Charge: Positive charge and Negative charge.
3. Electric Current
The motion, or flow of Electric Charge in a conductor when an Electric Field is maintained.
4. Magnetic Field
Electric Charge in motion sets up, in the space around it, a Magnetic Field. It is a force.
5. Electromagnetism
The science of charge, and the forces and fields associated with charge.
6. Electromagnetic Spectrum
Distribution of electromagnetic radiation according to frequency or wavelength.
7. Applications of Electromagnets
Electromagnets are in use throughout society and several examples are listed below.
This basic STEM knowledge is essential for your understanding, enjoyment and education.
Please read through the information below before moving on to the “Build Instructions” page, where you will learn step-by-step how to build your electromagnet (link at bottom).
1. THE ATOM
Atomic Structure (3 basic particles): Proton, Electron and Neutron
The word atom is derived from the Greek word atomos, meaning indivisible.
We now know atoms are basically more or less complex arrangements of subatomic particles.
The subatomic particles, the building blocks out of which atoms are constructed, are of three different kinds:
1. The Electron, which is negatively charged.
2. The Proton, which is positively charged.
3. The neutral Neutron.
An atom is NOT CHARGED when the atom has the same number of electrons as protons. We say the atom is ‘neutral’.
An atom becomes CHARGED, when it either gains or loses an electron(s). The number of protons does not change.
An atom becomes positively charged, when it loses an electron(s). We call it a positive ion.
An atom becomes negatively charged, when it gains an electron(s). We call it a negative ion.
The process of losing or gaining electrons is called ionization.
2. ELECTRIC CHARGE
Electric charge can be positive (+) or negative (-).
The physical property of matter that causes it to experience a force.
Electric Charge will experience a force when placed in an electromagnetic field. More about the electromagnetic field below.
Electric Force: Both Positive and Negative Charges have a force, called the Electric Force.
The Electric Force is the resulting interaction of two charged particles which can be either attractive or repulsive.
We find experiments lead to two fundamental results that (1) like charges repel, (2) unlike charges attract.
Specifically, charges (+, +) or (-, -) will repel each other and unlike charges (+, -) will attract each other.
The ancient Greeks knew as far back as 600 B.C. that amber, rubbed with wool, acquired the property of attracting light objects. We describe this property today as saying the amber is electrified, or possesses an electric charge, or is electrically charged.
It is possible to impart an electric charge to any solid material by rubbing it with any other material, as when a comb is electrified in passing through dry hair.
Through observation, we are led to the conclusion that there are two types of electric charge: a negative charge and a positive charge. We find that a negatively charged body has acquired something extra, whereas a positively charged body has lost some of the same thing.
Experimentation suggests strongly that electric charges are not generated or created, but that the process of acquiring an electric charge consists of transferring something from one body to another, so that one body has an excess and the other a deficiency of that something.
We now know that this “something” consists of very small, light pieces of negative electricity, known today as electrons.
Electrons are one of the fundamental constituents of matter. If a body has an excess or deficiency of electrons, it is said to be charged and will be spoken of as a charged body or, or simply as a charge.
An Electric Field is said to exist at a point if a force of electrical origin is exerted on a charged body placed at the point.
3. electric current
The motion, or flow of electric charge in a conductor when an electric field is maintained within the conductor.
A Conductor is a material with “free” charges that will move in the conductor when a force is exerted on them by an Electric Field.
The Build Instructions page will explain more about wires.
In an electromagnet, the electric field is generated in the conductor by a battery.
There are two types of electric current, Direct Current (DC) and Alternating Current (AC).
Direct Current: If the field is always in the same direction, the current is called direct. A storage battery (car or truck battery) and dry batteries (D, C, AA, AAA, 9V batteries) are examples that use Direct Current.
Alternating Current: If the field reverses direction periodically, the flow of charge reverses also and the current is alternating. Typically, electric power lines and a home wall outlet (receptacle) will use Alternating Current.
In summary, if the ends of a wire are connected to the terminals of a battery, an electric field will be maintained within the wire and there will be a continuous motion of charge through it.
4. MAGNETIC FIELD
Electric currents produce magnetic fields.
The first magnetic phenomena to be observed were in so-called “natural” magnets, rough fragments of an ore of iron found near the ancient city of Magnesia (whence the term “magnet”). These natural magnets have the property of attracting to themselves unmagnetized iron, the effect being most pronounced at certain regions of the magnet known as its poles.
It was known to the Chinse as early as A.D. 121 that an iron rod, after being brought near a natural magnet, would acquire and retain this property of the natural magnet, and that such a rod when freely suspended about a vertical axis would set itself approximately in the north-south direction.
In 1819, a Danish scientist, Hans Christian Orsted, observed a connection between electrical and magnetic phenomena; a pivoted magnet (a compass needle) was deflected when in the neighborhood of a wire carrying a current.
It is convenient to adopt the point of view that a moving charge sets up in the space around it a magnetic field.
A Magnetic Field is said to exist at a point if a force is exerted on a moving charge at that point.
Regarding the magnetic properties of matter in general, the use of permanent magnets, as in galvanometers or permanent magnet speakers, magnetic fields can be produced without any apparent circulation of charge.
Remember, our Earth’s Magnetic Field, also known as the “geomagnetic field”, is generated by the movement of molten iron in the Earth’s outer core, creating electric currents that produce a magnetic field extending into space, where it interacts with the solar wind; this field is essentially like a large bar magnet tilted slightly off Earth’s axis.
5. ELECTROMAGNETISM
Electricity and Magnetism are two aspects of electromagnetism.
Electromagnetism is one of the fundamental forces of nature and is a branch of physics that involves the study of the electromagnetic force. It is a type of interaction that occurs between electrically charged particles.
Electromagnetism may also be thought of as a combination of electrostatics and magnetism, which are distinct but closely intertwined phenomena. Early on, electricity and magnetism were studied separately and regarded as separate phenomena.
The Electromagnetic Force is a force that acts between charged particles and is a combination of electrical and magnetic forces. Electromagnetic forces occur between any two charged particles.
Electric forces cause an attraction between particles with opposite charges and repulsion between particles with the same charge, while Magnetism is an interaction that occurs between charged particles in relative motion.
These two forces are described in terms of electromagnetic fields.
Hans Christian Orsted discovered that the two were related – electric currents give rise to magnetism. Michael Faraday discovered the converse, that magnetism could induce electric currents.
James Clerk Maxwell put the whole thing together in a unified theory of electromagnetism. Maxwell’s equations further indicated that electromagnetic waves existed.
Experiments of Heinrich Hertz confirmed this, making radio possible. Maxwell also postulated, correctly, that light was a form of electromagnetic wave, thus making all of optics a branch of electromagnetism.
The modern theoretical treatment of electromagnetism is as a quantum field in quantum electrodynamics.
6. ELECTROMAGNETIC SPECTRUM
The full range of electromagnetic (EM) radiation, organized by frequency or wavelength.
Radiation is energy that travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation.
The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays and gamma-rays.
Electromagnetic radiation has both electric and magnetic fields and travels in waves.
Wavelength refers to the distance from the peak of one wave to the peak of the next.
Frequency refers to the number of waves that pass by a given point in one second.
These properties are closely and inversely related: The smaller the wavelength, the larger the frequency,— and vice versa.
The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band.
Radio waves differ from light only in that the wavelength of the former is much longer than the latter.
7. APPLICATIONS OF ELECTROMAGNETS
Electromagnets are in use throughout society.
Electromagnets are very widely used in electric and electromechanical devices, including:
Motors and generators
Transformers
Relays
Electric bells and buzzers
Loudspeakers and headphones
Actuators such as valves
Magnetic recording and data storage equipment: tape recorders, VCRs, hard disks
MRI machines
Scientific equipment such as mass spectrometers
Particle accelerators
Magnetic locks
Magnetic separation equipment used for separating magnetic from nonmagnetic material
Industrial lifting magnets
Magnetic levitation, used in a maglev train or trains
Induction heating for cooking, manufacturing, and hyperthermia therapy
Remember, this knowledge is foundational to a STEM education. Learn it well.
You are encouraged to learn more about SCIENCE, TECHNOLOGY, ENGINEERING and MATH on your own, for both personal growth and profitable enjoyment.
Resource’s: University Physics – Sears * Zemansky AND others
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