Muscle contractions, or a startle reaction, can cause a person to fall from a ladder, scaffold or aerial bucket. The fall can cause serious injuries. If you must be close to power lines, you must first call your electrical utility company and they will assist you. Call and your local utility service for help. Wait for the electrical utility to come and they will tell you when it is safe to get out of your vehicle.
Never try to rescue another person if you are not trained to do so. If you must leave the vehicle e. Never touch the vehicle or equipment and the ground at the same time. Keep your feet, legs, and arms close to your body. Keep your feet together touching , and move away by shuffling your feet.
Never let your feet separate or you may be shocked or electrocuted. Shuffle at least 10 metres away from your vehicle before you take a normal step. Do not enter an electrical power substation, or other marked areas. Inspect portable cord-and-plug connected equipment, extension cords, power bars, and electrical fittings for damage or wear before each use.
Repair or replace damaged equipment immediately. Always tape extension cords to walls or floors when necessary. Do not use nails and staples because they can damage extension cords and cause fire and shocks. Use extension cords or equipment that is rated for the level of amperage or wattage that you are using.
Always use the correct size fuse. Replacing a fuse with one of a larger size can cause excessive currents in the wiring and possibly start a fire. Be aware that unusually warm or hot outlets or cords may be a sign that unsafe wiring conditions exists. Unplug any cords or extension cords from these outlets and do not use until a qualified electrician has checked the wiring. Always use ladders made with non-conductive side rails e. Place halogen lights away from combustible materials such as cloths or curtains.
Halogen lamps can become very hot and may be a fire hazard. Risk of electric shock is greater in areas that are wet or damp. Install Ground Fault Circuit Interrupters GFCIs as they will interrupt the electrical circuit before a current sufficient to cause death or serious injury occurs. Make sure that exposed receptacle boxes are made of non-conductive materials.
When you turn on the light switch the circuit is closed and electrons can move freely to turn on your lights. When you turn off the switch it opens the circuit not allowing the electrons through and turning off your lights. When light bulbs burn out the small wire connecting the circuit inside the light bulb breaks and stops the flow of electrons. Energy flows through our entire world and understanding how electricity works is just the beginning.
Of course, most of the electricity in your life is not connected to a single battery as in the example above, but the understanding on a basic level is very interesting. Electricity literally powers everything in our lives and a world without it would be very different. Understanding how these things work lets us enrich our knowledge of the world around us and provides us with practical information we can use in our everyday life.
Electricity is all around us and is used in more interesting ways than just light bulbs and batteries. BioEnergy Consult. This site uses Akismet to reduce spam. Learn how your comment data is processed. Email Address. It's not to scale but helpful for understanding how an atom is built. A core nucleus of protons and neutrons is surrounded by orbiting electrons. Every atom must have at least one proton in it. The number of protons in an atom is important, because it defines what chemical element the atom represents.
For example, an atom with just one proton is hydrogen, an atom with 29 protons is copper, and an atom with 94 protons is plutonium. This count of protons is called the atom's atomic number. The proton's nucleus-partner, neutrons, serve an important purpose; they keep the protons in the nucleus and determine the isotope of an atom.
They're not critical to our understanding of electricity, so let's not worry about them for this tutorial. Electrons are critical to the workings of electricity notice a common theme in their names?
In its most stable, balanced state, an atom will have the same number of electrons as protons. As in the Bohr atom model below, a nucleus with 29 protons making it a copper atom is surrounded by an equal number of electrons. As our understanding of atoms has evolved, so too has our method for modeling them. The Bohr model is a very useful atom model as we explore electricity. The atom's electrons aren't all forever bound to the atom.
The electrons on the outer orbit of the atom are called valence electrons. With enough outside force, a valence electron can escape orbit of the atom and become free. Free electrons allow us to move charge, which is what electricity is all about. Speaking of charge As we mentioned at the beginning of this tutorial, electricity is defined as the flow of electric charge.
Charge is a property of matter--just like mass, volume, or density. It is measurable. Just as you can quantify how much mass something has, you can measure how much charge it has. In order to move charge we need charge carriers , and that's where our knowledge of atomic particles--specifically electrons and protons--comes in handy. Electrons always carry a negative charge, while protons are always positively charged.
Neutrons true to their name are neutral, they have no charge. Both electrons and protons carry the same amount of charge, just a different type. A lithium atom 3 protons model with the charges labeled.
The charge of electrons and protons is important, because it provides us the means to exert a force on them. Electrostatic force! Electrostatic force also called Coulomb's law is a force that operates between charges. It states that charges of the same type repel each other, while charges of opposite types are attracted together.
Opposites attract, and likes repel. The amount of force acting on two charges depends on how far they are from each other. The closer two charges get, the greater the force either pushing together, or pulling away becomes. Thanks to electrostatic force, electrons will push away other electrons and be attracted to protons. This force is part of the "glue" that holds atoms together, but it's also the tool we need to make electrons and charges flow!
We now have all the tools to make charges flow. Electrons in atoms can act as our charge carrier , because every electron carries a negative charge. If we can free an electron from an atom and force it to move, we can create electricity.
Consider the atomic model of a copper atom, one of the preferred elemental sources for charge flow. In its balanced state, copper has 29 protons in its nucleus and an equal number of electrons orbiting around it. Electrons orbit at varying distances from the nucleus of the atom. Electrons closer to the nucleus feel a much stronger attraction to the center than those in distant orbits. The outermost electrons of an atom are called the valence electrons , these require the least amount of force to be freed from an atom.
This is a copper atom diagram: 29 protons in the nucleus, surrounded by bands of circling electrons. Electrons closer to the nucleus are hard to remove while the valence outer ring electron requires relatively little energy to be ejected from the atom. Using enough electrostatic force on the valence electron--either pushing it with another negative charge or attracting it with a positive charge--we can eject the electron from orbit around the atom creating a free electron.
Now consider a copper wire: matter filled with countless copper atoms. As our free electron is floating in a space between atoms, it's pulled and prodded by surrounding charges in that space.
In this chaos the free electron eventually finds a new atom to latch on to; in doing so, the negative charge of that electron ejects another valence electron from the atom. Now a new electron is drifting through free space looking to do the same thing. This chain effect can continue on and on to create a flow of electrons called electric current. A very simplified model of charges flowing through atoms to make current. Some elemental types of atoms are better than others at releasing their electrons.
To get the best possible electron flow we want to use atoms which don't hold very tightly to their valence electrons. An element's conductivity measures how tightly bound an electron is to an atom.
Elements with high conductivity, which have very mobile electrons, are called conductors. These are the types of materials we want to use to make wires and other components which aid in electron flow. Metals like copper, silver, and gold are usually our top choices for good conductors. Elements with low conductivity are called insulators.
Insulators serve a very important purpose: they prevent the flow of electrons. Popular insulators include glass, rubber, plastic, and air. Before we get much further, let's discuss the two forms electricity can take: static or current. In working with electronics, current electricity will be much more common, but static electricity is important to understand as well.
Static electricity exists when there is a build-up of opposite charges on objects separated by an insulator. Static as in "at rest" electricity exists until the two groups of opposite charges can find a path between each other to balance the system out. A negatively charged object has an excess of electrons, otherwise it is either uncharged or positively charged.
The international standard SI unit of electrical charge is the coulomb C , or ampere-hour Ah in electrical engineering. Voltage — Also known as electric pressure, electric tension, or electric potential difference, voltage is the indicator of the difference between electric potential energy between two points, per unit of electric charge.
It can be caused by electrical current passing through a magnetic field, static electric field, time-varying magnetic field, or a combination of any of those three. A voltmeter measures voltage between two points in a system. Current — This is the movement of the electric charge.
Electrons moving through a wire in an electric circuit carry charge.
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