On my last post, I introduced and explained the first 8 goals from the total of 21 goals from my worksheet which I need to answer in order to demonstrate my understanding of EM forces. Of course, to learn I need to use sources which provide me with information. However, my teacher found a more productive way of learning, by using simulations and images. Anyways, the rest of the goals are answered below, starting from the ninth one.
EM9. I can describe the properties and interactions of magnets.
Magnets have three properties in common; they attract iron and materials that contain iron, they attract and repel other magnets, and one part of the magnet will always point north when allowed to swing freely.
Magnets interact in two different ways. They can either attract or repel each other. When unlike poles are brought together, they will attract each other. On the other hand, when like poles are brought close to each other, they will repel.
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| http://27gen.blogspot.com.br/2010/10/so-you-have-magnetic-personality.html |
The magnetic fields of the atoms in certain materials are arranged differently depending on whether they are magnetic or non-magnetic materials. Magnetic materials have all or most of its magnetic domains aligned in one direction. The magnetic domains of non-magnetic materials is the opposite, the domains aren’t aligned or point to random directions.
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EM11. I can explain the connection between electricity and magnetism (electromagnetism).
According to my science textbook, electromagnetism is the relationship between electricity and magnetism. An electric current produces a magnetic field. Electromagnetism cannot be seen yet, we can observe its effects by using a compass and an electric field. Usually, a compass’ needle aligns itself with Earth’s magnetic field. However, it will point in a different direction when a current is present. In other words, the needle will align with the magnetic field produced by the current.
EM12. I can outline the difference between DC/AC current and its uses
In an induced current, charges may flow in one direction or alternate direction. A current which consists in charges flowing through one direction is a direct current or DC. An alternating current or AC consists in charges which continuously move back and forth in a circuit. Whether an induced current is AC or DC depends on the direction in which the wire or magnet moves.
Direct current are used for simple circuits. On the other hand, an alternating current can be used to send electrical energy over great distances and for our everyday devices due to its ease of raising and lowering its voltage in the circuit.
EM13. I can explain why the Earth behaves like a magnet and the consequences of it.
Earth is considered to behave like a magnet since it has a magnetic field and magnetic poles. Both of the magnetic poles form a magnetic field, to which compasses align with. Also, by having a magnetic field, Earth can make magnets from ferromagnetic materials. By leaving an iron bar lying for years, the Earth’s magnetic field can attract its domains so strongly and make them line up in the same direction. 
EM14. I can explain the importance of grounding wires and using fuses/circuit breakers.
All of them are safety devices which prevent people from getting an electric shock. Grounding wires provide an alternate path for a current. This path provides a current's charges to flow from the circuit to the earth. One type of grounding wire is the third prong. A plug usually has two prongs which connect to the a house's circuit. Yet, have you ever wondered why some plugs have a third round prong? A third prong connects the appliance with the ground wire of a building. So, if a short circuit occurred, the charge would flow to the Earth, preventing you from having an electric shock.
Fuses are devices that have a thin strip of metal which will melt if there's too much current, to break the circuit and avoid fire. Hoever, when the fuse is used, it must be replaced in order to protect you. For this reason, circuit breakers are used to avoid replacing fuses. Circuit breakers also breaks a current when there's too much and compared to fuses, it is reusable.
Third Prong:
http://web.princeton.edu/sites/ehs/labsafetymanual/Image18.gif
Circuit Breaker:
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzSiKsHhERvn08ifHInKS_aT-RNGGpMhQ98gdowVl0hRXpUPOCyA9RuLjm_FuZJ4akTfw5p4lGPCq-4vTbhFA5_YavYbfbAv6BkUBhVR9Wp7T_3NE-EpdNYTBwLfp8DnzDlVLE1twVheI/s400/circuit-breaker.png
EM15. I can explain how an electromagnet works and cite applications for them.
An electromagnet is a solenoid with a ferromagnetic core. Its magnetic field is produced by the current in the wire and the magnetized core. The electromagnet’s strength can be increased in several ways: by increasing the current in the solenoid, by adding more loops of wire to the solenoid, by winding the coils of the solenoid close together, or by using a stronger ferromagnetic material for the core. It really useful since you can make act as magnet whenever you want, it can be turned on and off at any time. 
EM16. I can explain how a simple motor works (parts and function).
Electric motors are devices that use electrical energy to produce motion. In other words, it transforms chemical energy into mechanical energy. However, how does it work exactly? First of all, a battery is connected to the motor, which gives a push to the charges that are already present in the wire of the motor. The wire connects to the brushes which allow the current to go to the commutator, with which is connected. The commutator will then allow the current go to the armature. When the current is in the armature, its magnetic field will interact with the magnetic field of the permanent magnets which are next to each side of the armature. At this moment, the armature will act as a magnet, causing the the armature and the permanent magnet to repel each other. In other words, the armature will make a half turn. This will change the direction of the current since when the electrons reach the commutator, a new and faster impulse of electrons will push and make them follow their path. This process repeats various times to make the armature flip continuously, until the battery runs out. 
EM17. I can describe how a generator and a transformer work.
Generators are devices that transform mechanical energy into electrical energy. There are two types of generator: AC and DC generators. In an AC generator, the armature is rotated in a magnetic field, inducing an electric current in the armature and causing the current in the wire to change directions. DC generators work like electric motors yet, you spin the motor to produce electrical energy. Transformers are devices that increase or decrease voltage. There are two types of transformers,step-up and step-down transformers. Step-up transformers increase voltage and has its secondary coil with more loops than the primary coil. On the other hand, step-down transformers decrease voltage and its primary coil has more loops than the secondary coil.
Step down transformer:
 
Step up transformer:
EM18. I can explain the importance of transformers to power grids.
Transformers are important in the transmission of electrical energy from generating plants, in order to be safe. First, we use step-up transformer to increase voltage, to efficiently transfer current over long distances. However, the voltage must be decreased, by a step-down transformer, for the current to be safely used in homes. 
EM19. I can explain methods of power production and distribution.
There are numerous ways of power production and distribution. Some of them include: fossil fuels, nuclear energy, hydroelectric energy, biomass, solar energy, wind energy, and geothermal energy.
Fossil fuels are non-renewable energy source formed over millions for years from the remains of plants and animals. When burned, they release energy. They are transported to power plants, where they are burned to heat water. The steam from the water then increases in pressure, forcing the turbine to spin. The turbine is used to rotate a magnet encased in a generator at high speeds. As the magnet spins, electrons are produced, and they power the electricity grid.
Nuclear energy is energy provided from an atomic nucleus through nuclear fission. The nuclear energy is converted to steam energy (heat generated by the nuclear fission is used to heat water). This energy is used to drive a turbine generator (mechanical energy) and produce energy.
Hydroelectric energy is the production of electrical power through the use of the gravitational force of falling or flowing water. It is generated by taking advantage of the difference in height of water behind and in front of a dam. This water has potential energy. The water is fed down huge pipes and into large turbines where the water spins the wheels of the turbines which in turn are attached to large electrical generators.
Biomass are plant materials, vegetation, or agricultural waste that are used as fuel or energy source. The materials are gathered in big trucks and then transported to a biomass plant. There, the wastes are fed into the furnaces where they are burned. The heat created is used to boil water and the energy from the steam that is created, is used to rotate turbines and generators.
Solar energy is the energy received by the earth from the sun. A system absorbs solar energy (like a photovoltaic system) and then converts or transforms it into a storable form of energy.
Wind energy is energy received from the movement of the wind across the earth. Wind power is produced by using a wind generator which converts the kinetic energy available in the wind to mechanical energy.
Geothermal energy is the energy derived from the heat in the interior of the earth. There are three different types of power plants used to generate electricity from geothermal energy depending on the temperature, depth, and quality of the water and steam of the area. In all cases, the condensed steam and remaining geothermal fluid is injected back into the ground to pick up more heat. In some locations, the natural supply of water producing steam from the hot underground magna deposits has been exhausted and processed waste water is injected to replenish the supply. Most geothermal fields have more fluid recharge than heat, so re-injection can cool the resource, unless it is carefully managed.
EM20. I can describe the differences of 110v/220v and main advantages and disadvantages of each.
A higher voltage, 220v, provides homes with a major amount of force to push an electric current. With a fast moving current, more electricity can go to homes of a city. On the other hand, 110v provides with a smaller amount of force to push an electric current yet it is more common. Also, if you were to receive an electric shock, with 110 volts would be less painful than with 220 volts.
EM21. I can describe the advantages and disadvantages of electrical energy.
Some advantages of electrical energy are that it is easy to move from one circuit to another, it’s safe, and it can be transmitted for long distances. Some disadvantages include that it contributes to global warming and isn’t permanent during storms.  |
