EM.9-21

EM9. I can describe the properties and interactions of magnets.

EM10. I can describe how the magnetic domains are arranged in a magnetic/non-magnetic material.

EM11. I can explain the connection between electricity and magnetism (electromagnetism).

EM12. I can outline the difference between DC/AC current and its uses

EM13. I can explain why the Earth behaves like a magnet and the consequences of it.

EM14. I can explain the importance of grounding wires and using fuses/circuit breakers.

EM15. I can explain how an electromagnet works and cite applications for them.

EM16. I can explain how a simple motor works (parts and function).

EM17. I can describe how a generator and a transformer work.

EM18. I can explain the importance of transformers to power grids.

EM19. I can explain methods of power production and distribution.

EM20. I can describe the differences of 110v/220v and main advantages and disadvantages of each.

EM21. I can describe the advantages and disadvantages of electrical energy.

EM.9: A magnet is any material that contain iron and attracts iron. They are not new. They were discovered more than 2,000 years ago in Magnesia(now Turkey) and were first discovered as a rock which contained magnetite. And those rocks attracted materials containing iron. They also attracted or repulsed magnetic materials, which is called magnetism. In addition to that, one part of a magnet will always point north when allowed to freely swing. Every magnet has two ends, each one called a magnetic pole and a magnet’s magnetic effect is stronger at the pole. One side is labeled north pole and the other one, south pole. If you bring the north pole of one magnet and the south pole of another, the two attract each other. That’s because unlike poles attract. If two south poles, or north poles are brought together, they will repel, and that’s because like poles repel. This attraction and repulsion is called a magnetic force. (Force= push or pull that causes an object to move). A magnetic force is produced when magnetic poles interact.

Two negative charges repel
Two positive charges repel
A negative charge and a positive charge attract!

EM.10: Magnetic domain= group of atoms that have magnetic fields aligned;

The directions that the domains point to determines if the material is a magnetic material or a non-magnetic material.

Non-magnetic material= Domains point to random directions; the magnetic field of some domains cancel magnetic fields of other domain. The material is not a magnet.

Magnetic material= Most domains point to same direction. In a magnetized material, all or most are arranged in the same direction; the magnetic fields of the domains are aligned.

The left one is a magnetic domain and the left one is a non-magnetic domain

EM.11: Both magnetism and electricity can create a magnet; you can’t have electricity without magnetism and vice versa; they are both able to create each other thus why most materials aren’t magnetic;

EM.12:

AC- depends on the vibration of the electrons when the current is on and the charges move back and forth. In other words, electrons move back and forth. Produced from magnet. It has an advantage over DC; it can be easily lowered to a higher or lower voltage meaning the high voltage can be used to send electrical energy to big distances. And the voltage can also be reduced, making it safer for everyday use.

DC- depends on the movement of the electrons and the charges flower in one direction only. In other words, the electrons flow continuously from one end to the other. When the battery runs out, the current stops. Produced from battery.

EM.13: The Earth behaves like a bar magnet, because it has a magnetic field surrounding it and two magnetic poles.

It has a liquid core that contains iron and it’s believed that as it moves/spins it creates an electric current that makes a magnetic field around the itself. The magnetic field and the two magnetic poles makes the Earth act like a huge magnet and also attracts like one. Thus why the magnetized needle of a compass always points north.

Consequences of it are:

-Since the Earth produces a strong magnetic field, it can make magnets out of ferromagnetic materials;

-Affects the movement of electrically charged particles in space;

Earth as a giant magnet

EM.14: Ground wires are on top of buildings and when thunder strikes the electricity goes to the street(ground). They are needed for safety. Using fuses/circuit breakers prevent further damage that electrical appliances could have; they stop current from breaking when they are getting hot.

EM.15: Electromagnet= solenoid with a ferromagnetic core; it is a strong magnet that can be turned on and off; its magnetic field can be a lot stronger than the magnetic field of the current;

They are used in audiotapes, videotapes, computer hard drives, and credit cards. They are also used to lift hard objects.

Credit cards: one of the appliances electromagnets are used in

EM.16:

1.)  Battery gets connected to wire

2.)  A current is created around the armature producing a field around it

3.)  Current continues to brush, to commutator, to armature, to right side of the armature, to commutator again, to brushes, etc. and the process continues

4.)  While this is going on, since the North pople attracts the South pole and the South pole attracts the North pole, the armature flips and the right side of it flips to the left, and the left side of it flips to the right

5.)  The commutator flips which makes the armature to do so too, making the brushes disconnect from it and the current to stop. When it aligns itself again with the north and south poles, the armature flips all the way and the commutator goes back to its initial position, where the brushes connect to it again and the current continues on. The right side which was moving forward, towards the battery begins to moves away once it flips sides and the left side which was moving away from the battery starts moving towards it once it flips. The sides the current moves always flips whenever the armature flips sides.

(get picture of armature)

The main parts of it are the following->

Brushes- They conduct the current to the armature. They do not move;

Commutator- Flips/rotates with armature; the direction of current changes with each half turn so that the armature spins endlessly;

Armature- Current is in opposite directions on each side of armature, which cuses one side to move up and the other to move down;

EM.17: A generator transforms mechanical energy into electrical energy. It’s the opposite of an electric motor; Electric motor= uses an electric current in a magnet field to produce motion; Generator= uses motion in a magnetic field to make an electric current.

In other words, a generator uses the energy of another material(windmills) to make energy. It doesn’t use electricity and instead uses magnets to produce it.

There are two types of generators:

AC generators- When the current goes back and forth and there is not a direct path;

DC generators- When the current goes straight continuously;

Its parts are:

-Crank: it is used to rotate the armature

-Slip ring: are attached to ends of armature

-Armature: current is induced in it as it rotates

-Brush: current leaves generator through brushes

A transformer increases or decreases voltage. It has two separate coils of insulated wire wrapped around an iron core; one is the primary coil(which is connected to a circuit with a voltage source and an alternating current) and there is the secondary coil(which is connected to a separate circuit that doesn’t have a voltage source)

There are two types of transformers. If the number of loops in the primary and secondary coils of a transformer is the same, then so is the voltage as it started off.

Step-up transformer= increases voltage; if the secondary coil has more loops than the primary coil, the voltage in the second one will be greater.

Step-down transformer= decreases voltage; if there are fewer loops in the secondary coil than the primary coil then it is a step-down transformer.

A transformer

EM.18: Transformers are needed to power grids because:

-They speed up the process of getting the energy from the plant to the houses/buildings;

-So that you have the right amount of voltage to make the product work;

-So that you don’t have an exceeded amount of voltage;

EM.19: There are various ways to produce energy:

-Hydroelectric Energy: Mechanical->Electrical;

Advantages: Reliable; clean; safe; controls amount of energy generated(flow of water)

Disadvantages: Takes a lot of space; expensive; takes land of people; affects environment

Nuclear Energy: Thermal->Mechanical

Advantages: Doesn’t increase global warming; generates a lot of energy; doesn’t take a lot of space to build

Disadvantages: Dangerous; Leftover waste; needs water to construct; hard to control

Biomass: Thermal-> Mechanical-> Electrical

Advantages: Plants trees to compensate; efficient way to get rid of organic waste; renewable

Disadvantages: Pollutes; difficult to produce lots of energy; burning; not cost efficient

Solar Energy: Light-> Heat-> Electric Mechanical-> Electrical

Advantages: Renewable source; clean; no greenhouse gases; free energy

Disadvantages: generates energy only during daytime(because of Sun); expensive; unattractive

Wind Energy: Mechanical-> Electrical

Advantages: Clean; doesn’t occupy grand space; not dangerous; energy is cheap; renewable

Disadvantages: Not cost-efficient; kills birds(flying animals); not reliable

Geothermal Energy: Thermal-> Mechanical-> Electrical

Advantages: No pollution; free

Disadvantages: Installing is not cheap; limited area

Fossil Fuels: Chemical-> Electrical

Advantages: Easy to be transported;

Disadvantages: Not renewable; pollutes a lot

(explain what they are+ get pics)

EM.20: The difference is that 110V has a slower/weaker push and 220V has a faster/stronger push.

Advantages of 110V:

-Less dangerous

-It is more commonly found in the USA

Disadvantages of 110V:

-Gets to places slower

Advantages of 220V:

-Gets to places faster;

-Can be transferred to long distances more efficiently

Disadvantages of 220V:

-More dangerous

-Less commonly found in the USA

EM.21:

Advantages of electrical energy are:

-It is clean;

-It’s easy to move from one circuit to another;

-Transmitted to long distances;

-It is safe;

Disadvantages are:

-Pollutes;

-Can be dangerous if one doesn’t take precautions;

-May cause health problems because of the electric and magnetic fields that are formed;

Bibliography for pictures:

http://www.google.com.br/imgres?um=1&hl=pt-BR&sa=N&biw=1280&bih=629&tbm=isch&tbnid=tZBGv--XbYZwPM:&imgrefurl=http://chemwiki.ucdavis.edu/Physical_Chemistry/Quantum_Mechanics/Atomic_Theory/Electrons_in_Atoms/Multi-electron_Atoms&docid=0FCSSiWJlafzNM&imgurl=http://chemwiki.ucdavis.edu/%2540api/deki/files/4338/%253Dattraction_and_repulsion.JPG&w=513&h=154&ei=XxuQT_ubMY
eQ9QSA35GlBA&zoom=1&iact=hc&vpx=688&vpy=182&dur=3444&hovh=123&hovw=410&tx=173&ty=54&sig=11
4836916919842941390&page=1&tbnh=53&tbnw=178&start=0&ndsp=18&ved=1t:429,r:4,s:0,i:74  

http://www.google.com.br/imgres?um=1&hl=pt-BR&biw=1280&bih=629&tbm=isch&tbnid=r8ijY8B5yUsEmM:&imgrefurl=http://www.delsea.k12.nj.us/Academic/Classes/highschool/science/physics/FirstYear/Units/Unit07/Notes/BasicMagnetism.htm&docid=pdOvpvew51YbkM&imgurl=http://www.delsea.k12.nj.us/Academic/Classes/highschool/science/physics/FirstYear/Units/Unit07/Notes/Images/Magnetvsnonmag.png&w=465&h=407&ei=ExyQT6HUDIeO8wT2lv2UBA&zoom=1&iact=hc&vpx=122&vpy=189&dur=176&hovh=210&hovw=240&tx=146&ty=123&sig=114836916919842941390&page=2&tbnh=129&tbnw=147&start=18&ndsp=27&ved=1t:429,r:21,s:18,i:153

http://stargazers.gsfc.nasa.gov/resources/magnet_in_space.htm

http://www.google.com.br/imgres?um=1&hl=pt-BR&biw=1280&bih=629&tbm=isch&tbnid=rK1SE40GFkxk9M:&imgrefurl=http://www.mybudget360.com/endgame-credit-card-nation-40-year-credit-card-bull-market-over/&docid=brl41r2dOeaTFM&imgurl=http://www.mybudget360.com/wp-content/uploads/2011/05/creditcards.jpg&w=470&h=314&ei=bx2QT9-eMIbc9ASb0pWhBA&zoom=1&iact=rc&dur=377&sig=114836916919842941390&page=1&tbnh=153&tbnw=199&start=0&ndsp=10&ved=1t:429,r:0,s:0,i:70&tx=120&ty=69

http://www.google.com.br/imgres?um=1&hl=pt-BR&biw=1280&bih=629&tbm=isch&tbnid=uN8wP8_Xn8HZ9M:&imgrefurl=http://www.atltransformers.co.uk/pages/basic-principles.htm&docid=zEn7EOAUvG9qIM&imgurl=http://www.atltransformers.co.uk/uploads/images/763px-Transformer3d_col3_svg.png&w=763&h=573&ei=_R2QT8uULI6w8AStutmABA&zoom=1&iact=hc&vpx=966&vpy=146&dur=386&hovh=194&hovw=259&tx=109&ty=106&sig=114836916919842941390&page=1&tbnh=127&tbnw=159&start=0&ndsp=18&ved=1t:429,r:5,s:0,i:74