Wednesday, April 25, 2012

Electricity and Magnetism Unit

The unit that we just finished learning is the interaction between electricity and magnetism. We had different topics, and various goals that we were supposed to complete to make sure we had learned what we were supposed to. The goals that we have to be able to explain are the ones from EM9 - EM 21. I will be addressing what I know about each topic.

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

The properties of a magnet :
-Usually made of metal
-Material that attracts iron and material that contain iron.
-A good conductor
-Is hard and solid
-All magnets have an end pointing north and one pointing south, called magetic pole
-The magnetic effect of a magnet is strongest at the poles
-It is surrounded by a magnetc field
-It has an attraction or repulsion between magnets, a magnetic force.

The interaction of metals are really similar to the interaction between electrical charges.

As you can see in the picture the poles that are alike repel each other, however; poles that are unlike each other attracts one another.

The reason why they react when getting closer is because of the magnetic field around them. The magnetic field enables the magnets to interact without even touching each other. 

The magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole. 

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

A magnetic domain is a grouping of atoms that have their magnetic fields aligned. But what is an atom? An atom is a particle that is composed of neutrons and protons in the nucleus and electrons surrounding it. 
  • The entire domain acts like a bar magnet wih a north pole and a south pole.
Domains are alligned differently in magnetized iron and unmagnetized iron.
  • Unmagnetized iron 
 In an unmagnetized iron the domains point all to different directions. These arrows represents the force of the domains, it shows in what direction the force of the domain is working on.
  • Magnetized iron
In a magnetized iron all or most of the domains point to the same direction. The magnetic field of the domains are aligned, all the domains puts their force to the same direction.

Strong magnets are the ones with its domain aligned. The materials that show this property are known as ferromagnetic material. Iron, nickel and others are examples of ferromagnet material.  

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

Electromagnetism is the relationship between electricity and magnetism, the relationship between them is the electric current producing a magnetic field.
As you can see in the picture, the picture of the left, the compasses points north because it aligns itself with the earth's magnetic field. However; that only happens when there isn't any other current around it. Because when an object with a current, for example a wire, is present the compass needles will align itself with the magnetic field from the current of the wire.  

The magnetic field produced by a current has three characteristics,
- The field can be turned on and off
To do so, you simply turn the current on or off. An example is the light. You have the switcher to turn the light on or off. 
-It can have it's direction reversed 
You can change the direction of the magnetic field by reversing the direction of the current. Because when current reverses the magnetic field also reverses. 
-It can have it's strength changed
If the number of turns, loops, or coils increases you can increase the strength of the magnetic field. A coil of wire with a current is called a solenoid. 

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

For you to understand the difference between the two types of current, you have to know what is to induce an electric current. An electric current is induced in a conductor when the conductor moves through a magnetic field. Generating an electric current through the motion of a conductor through a magnetic field is called electromagnetic induction.

To induce a current in a conductor, either the conductor can move through the magnetic field or the magnetic itself can move.

Direct Current -
In an induced current, charges can flow in one direction only or alternate the directions. A current in which charges flow in only one direction is called direct current, in a simple way, DC. A direct current can be induced from a changing magnetic field or produced from an energy source like a battery. In the battery the charges will flow from one side to the other, until both sides are balanced.
Alterning Current -

The alterning current is all explained in its name! The current keeps alterning its direction repeatedly. It consists of charges moving back and forth in a circuit.
Alterning current has a greater advantage over direct current because it's voltage can be easily raised or lowered to a higher or lower voltage. Which means that electrical energy can be sent from a long distance in a high speed, but be reduced to a safer level when getting to the right point, which can be safer.


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

Why does a compass always points north when no current is around it? The answer to this question is because the earth has its magnetic field surrounding its poles. The Earth is similar to a magnet. It has two poles, and a magnetic field surrounding its poles. Because the Earth works like a magnet, the compass' needle points north because it aligns itself with the Earth's magnetic field.
Earth's magnetic field extends into space, where is a place full of electricalle charged particles. Earth's magnetic field affects the movements of electrically charged particles in space. Earth experiences a solar wind, which is a stream of electrically charfed particles flowing at high speed from the sun. The solar wind pushes against Earth's magnetic field, and the region which it is shaped is magnetosphere.

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

When we have contact with a wire with a current we can be shocked, it might hurt a little but it can even be fatal. So for people's safety grounding wires and circuit breakers were created.
Sometimes the electric charge can flow through the person rather than through the wire. It is considered a short circuit between the wire and the person. A short circuit is a connection that allows current to take the path of least resistance.
We always need to know that there is a difference between the electrical discharge that you feel from the carpet and an electrical discharge from touching a high-voltage wire.
The Grounding is a really important role in electrical safety. One way to protect people from electric shock and other electrical danger is to provide an alternate path for electrical current.
A circuit is electrically grounded when charges are able to flow directly from the circuit into Earth in the event of a short circuit.
A method of grounding is to use a third prong on a plug, like the image below.

The third prong which is round, connects any metal pieces of the appliance to the ground wire of the building. If a short circuit occurs in the appliance, the electric charge will flow directly into Earth. So anyone who touches it will be safe.

The Breaking Circuit are used to break circuits that are overloaded and can result in danger. In order to prevent circuits from overheating,  fuses and circuits breakers are added to circuits.
A fuse is a device that contains a thin strip of metal that will melt if there is too much current through it. If the metal melts or blows it breaks the circuit. If the circuit is broken, the current stops. Which prevents danger.
However; a disadvantage of a fuse is that, once it is burned it has to be replaced. To avoid having to replace it, there is a new device called circuit breakers. A circuit breaker is a reusable safety switch that breaks the circuit when the current gets too high.

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

Your life will be much easier if you know what is a ferromagnet and a solenoid before learning how an electromagnet works. A ferromagnetic is a material of iron that has a strong characteristics of metal. A solenoid is a coil of wire with a current. 
So, now that you know what is a ferromagnet and a solenoid i will explain what is an electromagnet and how it works. An electromagnet is a solenoid with a ferromagnetic core. The magnetic field of an electromagnet is produced by the current in the wire and the magnetized core. An electromagnet is a strong magnet that can be turned on and off. 

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

Moving an object over a distance is called energy. When the energy interacts with eletric current it is called electrical energy, and when an object has an energy that it is able to move it is called mechanical energy.
Energy can be transeformed from one form into another. When a wire with a current is placed in a magnetic field, electrical energy is transformed into mechanical energy. It happens when the magnetic field current causes the wire, or another conductor to move.

To transform the electrical energy to mechanical energy we usually use a device called an electric motor.

This image represents an electric motor. The yellow circle is called a commutator.
A commutator is a ring split in half, in which each half is attached to one of the armature which are the two wires coming out of the commutator. 
The wires that come out from the commutator is called armature. The armature is the wire that connects with the commutator and is also the object that will turn continuously.
The huge blue object around the armature is the permanent magnet. The permanent magnet will always be around the armature to keep the magnetic field around the motor.
The commutator is connected by the white lines coming from the green baterry. In the end of each white line has an object called brush, that touches the commutator. Though we can't really see it in this picture.

The function of each part of the motor :
-Brushes: The brushes conduct current to the armature.
-Armature: The armature is attracked by the magnetic field and it alligns itself correctly with the magnetic field, moving up or down.  
-Commutator: The commutatot rotates with the armature. It repeadetly reverses the flow of current through the armature.

How the motor works? 
For a motor to work, you have to make the armature spin continuously. When the energy source pass by the brushes to the commutator, the current flows in one direction to the armature. But because of the magnetic field that is created by the permanent magnet, the current has to align itself with the magnet, as a result the armature turns to a vertical position. However, the current keeps reversing it's direction, which makes the armature spin continuously. 
This is an image showing how the motor works:

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

A generator, opposite from the motor, uses motion in a magnetic field to produce an electric current. It transforms mechanical energy into electrical energy. But to understand how a generator works you have to know what is an electromagnetic induction and the types of current, (the types of current we already saw in EM.12, if you forgot go review it!) 

An electric current is induced in a conductor when the conductor moves through a magnetic field. To th generate an electric current from the motion of a conductor through a magnetic field is called electromagnetic induction. That is to say, when you use the motion, the movement of a conductor and as a result electric current is produced. 
To induce a current in a conductor, either the conductor or the magnet can move through the magnetic field. 

The picture in the upper side you can notice that the coil is moving up when the south pole is near the conductor, and besides it the coil is moving down when the north pole gets near the conductor. A current is induced in a coil of wire when the coil moves in a magnetic field. And the opposite occurs in the picture below. A current is induced in a wire when a magnet moves through a coil of wire. 

As you can see in the picture the parts of a generator and parts of the motor are really alike, there is only
 one difference, which is the crank. 

This is a simple AC generator. As the crank is turned, the armature rotates in the magnetic field. One side of the armature moves up and the other moves down. This motion induces a current in the wire. After the armature turns halfway, each side of it reverses direction in the magnetic field. The side that moved up moves down, and vice versa. AS the armature turns, slip rings turn with it. The slip rings my remind you of the commutator in a motor. As they turn, they make contact with the brushes. The brushes are connected to the rest of the circuit, in which the generator becomes an energy source. 

The crank is used to rotate the armature, and the slip ring is really similar to the commutator from the motor. 

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

A transformer is a device that increases or decreases voltage. A transformer consists of two separate coils of insulated wire wrapped around an iron core. 
The primary coil, the first coil, is connected to a circuit with a voltage source and alterning current. The other coil, the secondary coil, is connected to a separate circuit that does not contain a voltage source. 

There are 2 types of transformers, the step-up or step-down transformer. The step-up transformer has less coil around the primary coil and more in the secondary coild so that it can increase the voltage. 
There are more loops in the secondary coil, therefore; it increases the voltage. In the other hand, the step-down transformers do the opposite as the step-up transformer. As you predicted the step-down transformer decreases the voltage, having more loops in the primary loops than in the secondary loop, like this:
Transformers are really important because they can be efficiently used in transmissions of electrical energy. For example, to transmit electrical energy from long distances, the best way is to transmit it in high voltage, but when getting to the place where the energy will be used, the transformer can decrease the energy for our safety. 

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

There are a lot of different methods of power production and distribution, here are some of them. 
-Fossil Fuels
-Nuclear Energy
-Hydroeletric Energy
-Solar Energy
-Wind Energy
-Geothermal Energy

I will explain one of the examples which is Solar Energy. The conversion that happens is from kinetic electromagnetic to kinetic electrical energy. 
The solar energy like its name, gets the energy from the sun to produce energy. 

Some advantages of the solar energy are:
-It is renewable
-It is a clean transformation 
Some Disadvantages of the solar energy are:
-It is only possible when sun is present, so mostly during the day. But days that are cloudy is difficult. 
-It is also really expensive, which makes harder for people to use this type of energy. 

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

The difference between 110v and 220v is that 220v is stronger and more efficient.

Some reasons why 220v is better, is because you lose less energy, it is cheaper, stronger and more efficient.  Since it is high voltage during the transmission of energy, it generates less heat and therefore loses less energy. Also, the wires for 220v are thinner, so it is a lot more cheaper than 110v. But a disadvantage is that it is more dangerous, if you get shocked it will have a greater impact than 110v. 

The advantage of 110v is that, it is safer. There isn't enough voltage to use a path to the ground, so it's a lot harder to get shocked. Some disadvantages are that it is expensive plus it's weaker than 220v. 

 Here in Brazil we use both 110v and 220v because when they started installing this a long time ago they didn't plan and were influenced by both the European (110v) and American (220v) system and installed both and to change it now, would be really expensive. We need 220v because some of the electric objects need more power to work, like the freezer. But simple electronic materials like computers can be used in 110v. 

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

Electrical energy is the presence and flow of an electric charge through a conductor. 
Some advantages of it are:
-It is clean
-It's fast
-It's efficient
-It's easy to distribute in different places
Therefore, many people use electrical energy. But, the way we get the energy is a disadvantage. It polutes the environment and it is unsafe. 

Friday, February 17, 2012

What we did after the break

Hey guys, its been a long time since the last post about our classes. After the winter break we started our class by creating an eletro magnet, eletric motor and we also revised 8 points of electricity and magnetism.

Electro  Magnet
To start, we got together in groups of 3 and created an electro magnet to introduce us to electromagnetism. We took a wire and wrapped it around the nail,then we took both ends of the wire and connected each of the ends with the end of each poles of the battery. The wires that were rolled around the nail started to attract the paper clips. That happened because of the eletric field that was produced by the current. It was really fun making this electro magnet in groups because when we were successcul, when the nail attracted paper clips, we got excited and started challenging ourselves to be able to attract more and more paper clips.

Eletric Motor
To build and eletric motor was an individual project, in which we were supposed to search on the internet on how to create a motor, build it and show it to our peers.

These were the materials I used to create my motor:
-Transparent Mc Donald's plastic cup
-2 circular magnets
-2 cooper wires covered with plastic having the little grabbers on both ends
-a thin cooper wire
-2 clips
-2 elastics
- big cylindrical battery

I watched this video, and tried to make the same motor:

It was kind of hard to build it, but I tried to copy each step so I would make the motor work. I had to try various times before it worked. The main issue in my motor was the thin cooper wire, because it wasn't a circle, it was hard to the wire stay still as a circle. Also another part that was hard was being able to balance thw thin wire in the middle of the magnets. To make it work we were supposed to give it a ligt push, but the wire was so ligth that it moved places very easily. But after many attempts I was successful.This is how my motor worked:
I think the motor worked because when you connected both sides of the wire to the battery, the battery pushed the electrons and the electrical field was produced because of the movement of electrons. When the electricity got to the top of the motor, where the magnet is below the wire, there will be opposite charges of the magnet and the charge of the electricity from the wire, so it will turn.

8 Points of Eletricity and Magnetism
EM1: I can explain how eletric charges interact
EM2: I can give examples of how charges can be transferred between materials and explain them.
EM3: I can explain how an eletric current is produced.
EM4: I can compare conductors with insulators.
EM5: I can explain how resistance affects current.
EM6: I can use Ohm's law to calculate resistance, current or voltage.
EM7: I can build series and parallel circuits and descrive its parts.
EM8: I can explain the relationship between power, voltag and current.

These are the 8 points that we revised in class, making a packet that we wrote the important points of each topic.
In class we did 8 groups, each group was responsible to explaining one topic. Each group made a poster, with a visual to explain their part, and that's when we took notes in our packet about Magnetism and Eletricity.

EM1 : I can explain how eletric charges interact
-Opposite charges attract each other while same charges repel each other.
The red balls represents the positive charges, and the blue represents the negative charge. In the first example it shows how two positive charges repel each other, showing both arrow pointing to opposite sides. While the second picture, shows the positive and negative charges attracting  each other.

EM2: I can give examples of how charges can be transferred from between materials and explain them.
There are 3 types of tranferring energy:
1.Friction: Rubbing one uncharged object with another.

2. Conduction: Transfer of electrons from a charged object to another object by direct contact.

3. Induction: ovement of electron to one part of an object that is caused by the eletric field of a second object.
  It is important to know that charges are neither created nor destroyed.

EM3: I can explain how an eletric current is produced.
Eletric current is the continuous flow of eletric charges through a material.
-Charges move but energy doesn't.

Eletric Current is produced when 2 wires are connected to both sides of a battery and that makes the electrons flow. But this is a simple example, you can make it more complex. By adding more batteries, current, changing the material of the wire, the teperature, etc.

EM4: I can compare conductors with insulators:
-A conductor is a material through which charge can flow easily.
-An insulator is a material by which charges cannot flow easily, bound tightly with the atoms, do not move easily.
example of conductor :

An example of insulator:

EM 5: I can explain how resistance affects current.
Resistance is the measure of how difficult it is for charges to flow through a material.
The greater the resistance there is less current.

4 factors that can affect resistance:
-the material of the wire
-the length of the the wire
-the diameter of the wire
-the temperature of the wire.

EM6: I can use Ohm's law to calculate resistance, current or voltage.
Resistance = voltage/current

If resistance increases the voltage increases, if the resistance decreases current increases.

EM7: I can build series and parallel circuits and describe its parts.

There are 3 parts in a circuit:
- Energy source: The battery makes the charge move around the circuit, gives the push.
- Resistor: The light bulb transform electrical energy to light.
-Switch: open or closes thw circuit.

EM8: I can explain the relationship between power, voltage and current.

Power = Voltage X Current

Power: the rate at which energy is transformed from one form to another.
Voltage: Force that pushes the electrons
Current: the flow of eletric current

I liked doing this activity because it was an easy and effective way of learning or reviewing this topic. We could easily write the main points in our paper because the important things were the things that were written on the poster. We didn't have to go through all the pages of the book.


Monday, February 13, 2012

My Electricity Quiz !

Hello guys! This week, we were revising the topics about electricity and this is a quiz that I made about Electricity! Try to answer all of the questions and tell what you thought about it. Thanks (:

Monday, November 7, 2011

Cells Final Project : ZOINKS

Cells Final Project : ZOINKS
Project Goal :
The goal for this project was to show our teacher that we did really learn what she taught us about nutrients and cells. By doing this project we were supposed to do a story, game or any other entertainment way to help a teacher to teach her students in a funner and easy way.

My Goal :
My goal was to make a fun game, that would make the students interested and want to play the game. So they would learn in a fun way, which would be a b
etter way for them to remember what they learned.

I planned to make a board game. I wanted to make a board game, where various students would play the game at the same time. They would be asking questions to each other and the person who got the most answers right, and got to the end first would win the game. There would have two piles of flashcards, one pile of flashcards would be about Nutrients and the other pile about Cells. Each "house" of the board game would be written Nutrients or Cells, and they would have to pick a card from the corresponding pile of flashcards. Therfore, in some "houses" there would be ?? marks, which would be like a surprise card, which would give a present to the player giving an object of experiment. So the player that collected more objects would receive extra points in the end.

In the past 3 weeks, I had to make some changes. I decided that in my game, there wouldn't have the experiment objects, the reason was that, it w
ould be too complicated to find the tiny objects and to make it would be really hard. So I decided that, instead of the objects, the cards would give surpises like going steps foward or backwards. So it could be a postive or negative result, that would make the players more entertained and anxious. There was another change that I had to make in  my project. My teacher said that, if we were going to make board games, the games couldn't be question and answer. So I decided that I would gice tips in each paper, give tips about what i was talkin
g about, so I would show my teacher that I learned things. So in each paper, it had tips to the player get to the right answer. When it was the turn to the player 1, the player 2 would read the flashcards, so the player 1 wouldn't see the answer at the bottom of the flashcard.

How My Game Works?
1. The 2 or more players, will roll the dice to decide who starts the game, the one who gets the highest number will start the game.

2. The player will roll the dice again, and the number that comes out s/he will walk the steps and get to a 'home'. There will be written Nutrients or Cells, or ??. They will get the card according to the image.

3. The player 2 will read the back of the flashcard for the player 1, the back of the flashcards will have some bullet points giving tips of what is the answer.

4. In the bottom of the flashcard, it was written the answer. If the player got it right, he would stay where he was. If they didn't get it right, they would go back to where they started. 

5. The same would happen to the player 2, and the one who got first to the end, would win the game.

If you want to watch the video of my project, explaining how it works and showing you my board game, you can click to this link :

Self - Evaluation
In my point of view, my project wasn't that bad, but still was not the best I could do. I think my project was really simple and not very interesting. Another thing that I thought could be a problem is that I Butdidn't five enough tips in my flashcards. But overall, I thought that it wasn't so bad, I would play that game, therefore I wouldn't buy it. But if I was a teacher, I would play this game with my students, and if they had any questions answer them while playing, I think they would learn more easily. A point of my project that I liked was the board, I think I did a good work on doing the board. It took some time, but I gave my best to getting it pretty cool.

Friday, September 30, 2011



In the science class, I am learning about the transportations like passive and active. To learn more about these two transportations we did an egg lab. From which we were supposed to use two different liquids and let the egg inside of a bottle with the egg, and see the differences in the egg. Our goal was to see the way of transportation like diffusion, osmosis or facilitated diffusion and the transportation by the inside and outside of the egg.

In the beginning of the lab, we made predictions of what was going to happen with the eggs. So we chose two liquids that one was Alcohol and the other was Distilled water. We predicted that for the Alcohol the egg would shrink and for the Distilled Water the egg would grew.    

In all 3 days we took notes of the egg, analyzing it trying to look for any changes.
·         First day :
We chose the eggs that we were going to use to our lab. Those two eggs stayed in vinegar for 24hours so that the shell would be dissolved and only the membrane would last. In the first day, we took notes of the egg; we measured the egg’s circumference, mass and the quantity of liquid that was going in the bottle. We took notes of what the egg looked like, and we putted the egg inside of the bottle with the liquid.
·         Second day:
In the second day, we took the eggs out of the bottle carefully, and measured it again. To see if it happened something different with the egg and we took more notes of how the egg looked like. Then we putted the egg back again.
·         Third day:
In the third day, we did the same. We took out the eggs and measured it and took notes of the egg. After we cut both eggs to see how was inside of it.

Day 1
Day 2
Day 3
Distilled Water
Distilled Water
Distilled Water
Volume of solution(ml)


Possible Errors
·         Procedure:
-We putted the eggs in the plastic cup; it was a bad choice because the cup is open on the top. So maybe the liquid could have dissolved by the air. Next time we should get a container that is closed so we don’t get to risk the liquid from evaporating.
-When we were cleaning the bottles that had the liquids measured we always washed it before using it for the other liquid. Therefore, when putting the liquid out maybe some liquid could have stayed in the bottle, and liquid may have been wasted. Next time we have to be more careful and make sure all the liquid from the battle went out of it. 

·         Materials:
- We putted the eggs in a cup of plastic, and by that cup we couldn’t really see the egg, just the top. So it was hard to take some observations. So we couldn’t know if the egg was floating or not, and that would even had made an impact in the results. Next time we should use a transparent wide bottle, so the egg will fit in it and we will be able to see the egg and make some observations.
-When using the paper to clean and dry the egg, maybe in one of the eggs there was more liquid “attached” to it, so we may have wasted more water in the paper, by cleaning it. Next time we should make sure that the most possible amount of liquid from the egg was taken out before cleaning it. 

When water is used to balance the outside and the inside of the cell.
When whatever liquid is used to balance both outside and inside the cell, expect water.


·         The egg became really soft, but with a hard think inside, which was the yolk.
·         When we opened the egg, it was like a boiled egg, it was solid.
·         The egg was yellowish and hard, it seemed really full.
·         When we opened the egg, it “exploded” but we saw that it was liquid, like a normal egg but was more yellowish.

         My group expected reactions to each egg. We expected that the egg that was kept in the Alcohol would shrink and the egg in the Distilled Water the egg’s volume would increase. We were not sure; we guessed what would have happened. As a whole class, we discovered that the egg in the Alcohol was supposed to become solid and get smaller, the volume was supposed to each time decrease. The egg that was in the Distilled Water was supposed to get larger and the volume of the solution was supposed to decrease. Therefore; my group was a kind of different, because in the Alcohol instead of our egg’s circumference decrease till the end, our egg decreased but after it increased again. That was really confusing, and we had to think a lot about that, find some error that we did in the middle of the procedure. We got into a conclusion that we expect that the H2O found in the egg white would have been transported to the outside of the egg, which would be an osmosis, but the alcohol from the outside went into the egg by diffusion. So that impacted the egg by making it “grow” back again. In distilled water we got what we were supposed to get according to the class’ conclusion. In the Distilled Water the egg got really full, and yellowish. When we opened it, we could see that didn’t have changed a lot according to a normal egg. It was still liquid, but I think the egg might have exchanged liquids with the liquid outside of the cell.

         In my opinion, I really liked this lab, because we had the opportunity to learn a lot easier the types and functions of the transportations. It was even better because we learned by the fun way. I liked my team, because we helped each other, therefore; there were some things that we did wrong. Because we gave the part of taking notes just to one of the teammates, and I think that was wrong. But the other processes we worked in team, like measuring etc. I think I did help, but I did at the same time be a distraction in the team, even though I did help a lot in other aspects.