- How to build a motor
- How it works
- The three methods in which charges are transfered (Friction, Conduction, Induction)
- The difference between conductors (which are the materials that can carry charges within it) and insulators (the material that resists to the flow of electric current).
- The reaction between two opposite charges (attract) and similar charges (repel)
- The affect of resistance on an electric current (it makes it more difficult for the current to flow)
- The factors that can affect the current (width and length of the conductor)
- What is the voltage, resistance, current and how they are related.
Those are some of the concepts we began rediscovering during the first week.
____________________________________________________________________
There were several presentations that had the objective to inform the class about many parts of the Electricity unit. From definitions of terms to how the electrons flow in a conductor, the presentations gave us a clear notice of what we were to learn for that unit. The concepts explored were:
- What happens when two (opposite or similar) come together
- The ways to transfers charges
- What is an electric current and voltage and how they relate
- Conductors and Insulators
- Resistance x Current
- Ohm's Law
- Series x Parallel Circuits
-Difference between voltage, current and power
________________________________________________________________________________________________
WHAT HAPPENS WHEN TWO OPPOSITE POLES COME TOGETHER?
The basic answer to this would be that they attract. However, going into a bit more depth it is because the two poles have magnetic fields in which interact with each other when they are close. By having two opposite charges ( one being + and one being - ), the fields will become neutral when attached.
THE WAYS CHARGES TRANSFER:
There are three types of transfer: friction, conduction and induction.
The first is friction.
FRICTION happens when you rub two objects together. In analysis, the electrons are "ripped" off of one material and passed to the other. This happens when these elctrons have weaker bonds.
Conduction is when the two objects actually have a physical contact hense conduction also being called "charged by contact". An example would be your finger going inside an electrical outlet.
The last type of transfer, INDUCTION, is when a conductor (a material in which the current of electrons can flow like metal) is possible to be charged without actual physical contact. For example, when you walk on a carpeted floor about to go into your room, just before your hand grips the doorknob you are shocked. This is because the electrons in your hand come in contact with the charges of the doorknob.
ELECTRIC CURRENTS AND VOLTAGE: HOW ARE THEY RELATED?
An electric current is the rate of charge flow past a given point in a circuit and is measured in Amperes (Amps or A). Voltage, however, is the "push" that gets the current moving. Scientifically stating, the voltage is the difference in potential energy.
How they are related brings us to a whole new level. Imagine you have a small toy car sitting on your floor. To move that car you will need a force to give it its push. The car represents the current and your finger *which is whats pushing the car* is the voltage. Respectively, the harder the push, the faster the car will go. This is what happens with voltage and current. While in a circuit, if the voltage is of 220V, the current will move faster than being pushed by 110V.
CONDUCTORS VS. INSULATORS
Conductors and insulators are easy to be mixed up but have very different jobs. An insulator is a material that slows down the flow of electrons such as rubber. This is efficient in wires, for example, because it protects your hand from being shocked. A conductor, on the other hand, is a material that allows electrons to travel freely, such as metal.
Both of these factors, however, work together. In a copper wire, the copper is what carries the electrons (conductor) while the insulator is the rubber around that wire. This produces both efficiency and safety.
RESISTANCE AND CURRENT
Resistance and current are two rivals. While current struggles to move freely, resistance is what makes its day worse.
Imagine a hallway. Its afterschool and no one is present but you. You forgot your backpack at the far end of the hallway and you freely, without any struggle, are able to walk and retrieve it. This is an example of a circuit with little to no resistance. Now picture the same hallway but crowded with people whom are rushing to get to their classes. You class is the last room and you find yourself at the other end of the hall. Getting to your destination becomes difficult and smothering because of the high resistance, so that affects the way you move, or your "current".
Resistance or resistor is what opposes the path of electrons. The more resistance you have, the less current and vice versa. Resistors can be lightbulbs and hair dryers. The resistance, however, is not a bad thing. If you have a current moving too fast in a circuit, in a matter of minutes, that appliance may burn because of the heat produced. The resistance lowers the speed so that the electric appliance may function without over heating.
WHAT IS OHM'S LAW?
Ohm's Law states that the current through a conductor between two points is proportional to the potential difference across the two points (voltage). Basically, this states that the factors of a circuit (being resistance, voltage, power and current) are all connected to each other. For example, you have a circuit in which the baterry is of 9V (or volts), with overall resistance of 11 ohms but you do not have the current. To find this, you will produce the following formula:
R= V/I where R is for resistance, V for voltage and I for current. You plug in the values into the equation and get the following:
11 = 9/I
If you solve for I you will discover how much current (A) you have in that circuit given the resistance and the voltage.
CIRCUITS
There are two types of circuits we are familiar with right now. The PARALLEL CIRCUIT and the SERIES CIRCUIT.
WHAT IS THE DIFFERENCE BETWEEN SERIES AND PARALLEL CIRCUITS?
Parallel circuits are like your christmas lights you hang on your tree. If you may notice, some specific brands of christmas lights utilize a parallel circuit. Why? Because whenever one light in a wire burns out, the others continue to function correctly. Therefore, the lightbulbs do not depend on each other, they are independent from the other's malfunction. A series, however, is the exact opposite. If one light breaks, the whole circuit will not work. This is because the resistors are palce on the same wire, as you can see on the picture. So the current travels through the first bulb, then goes to the second, and so on. If the first one is broken, it interrupts that flow and the circuit turns into a hault.
WHAT IS THE DIFFERENCE BETWEEN VOLTAGE, POWER AND CURRENT
While voltage is the push that makes the current move, the power is the rate that the electric energy is transfered by the current. To find out the power in an equation, the formula is P= V X I. In other words, power is equal to the product of voltage and current. Power is measured in WATTS.
The difference between those three factors is that the voltage is the PUSH in a circuit, the CURRENT is what carries the electrons which is moved BY the voltage and the power is the resulting electrical energy transfered by the current.
___________________________________________________________________________-
Also, for the first week of class we were challenged to create a motor. This is the one I built:
Materials:
- Two soda cans
- Copper wire
- Plastic cup
- Ballpoint pen
- Hot glue gun
- Television
- Aluminum foil
- Tape
- Clips
- Patience
My motor was a bit more complicated to understand. Technically, the large sheet of aluminum foil would be stuck the screen of a television and with the large discharge of voltage it gives off when turned on, the electrons would travel down the copper wire to the first can and then transfer to the clip on the end of the can. By induction, the plastic cup in the middle would move as the electrons would transfer to the bits of aluminum foil on it. The same process would occur to the last can and the electrons would be dragged down to a ground connection such as the a metal tables legs that are pointed towards the ground.
Here is a video of how it is done:
http://www.wonderhowto.com/how-to-make-motor-from-plastic-cup-205520/
________________________________________________________________________________________________
So far, I've had challenges and successes during the course. The real challenge was to build the motor, which was highly dangerous since I could be shocked since there were insulators protecting me from the cans nor the clips. I tried many times and yet failed all of them. Exept for the last chance, and it worked out given the fact that I changed the copper wire that was hooked to the foil screen attached to the TV (I made it wider which affects the current). This taught me something important about the factors that can change the current: the temperature, the width, the length and the type of material. But, unfortunently, the motors only worked for about two to three seconds since I had no ground connection which is a material that simply leads down to the floor to dispose of the electrons.
My success was that, even though it underwent a lot of construction, my motor did work for a moment. By learning new things during the process, falling 7 times standing back up 8, I was successful to make it work, but too bad no one was there to see it actually happening.
________________________________________________________________________________________________
Electricity Quiz
We were asked to prepare a ten multiple question quiz we would use to challenge our classmates and by so study for the upcoming test. The test had to be a general summarization of all the concepts and could not include question that involved the definition of a term nor could it include the option *all of the above* (which was a bummer for many of the people).
My quiz is posted on the post below!
Nenhum comentário:
Postar um comentário