Magnets and more!

What I learnedThis section was a lot of fun! We started off by learning about magnets and electromagnets, and learned that a current carrying wire experiences a force when it is in a magnetic field. We also learned that change is very important to this section. In fact we learned that when a magnet moves through a wire, it changes the magnetic field thus inducing voltage and causing current. This is because in all objects, there are domains of atoms that spin, and when the domains are moving in the same direction, it creates a magnetic field, making the object a magnet. This shows that you can create and destroy magnets pretty easily by disrupting the direction of the domains by striking the magnetic object to align the domains. Going back, we started this section by learning about magnets. I learned that each magnet has a north and south pole, and that force always flows from south to north, so opposites will attract while like poles repel.  While still learning how magnetic fields work, we started the mini motor project! In this project we created our own mini motor, and learned how motors in general work. I learned that a motor works because a current carrying wire feels a for in a magnetic field. And in this case, the battery supplied energy for the current and the loop of wire and paperclips then carried the current to complete the circuit. The magnet supplied the magnetic field and so the wire loop felt a torue in the magnetic field when current ran through the wire when the side of the loop that was scraped of was vertical to the battery and magnet, thus the loop experienced a torque and turned, creating a mini motor! At this point we also learned how stoplights detect cars! In the ground there is a coil of wire in the pavement. So, when your car, which acts as a magnet runs over it the magnetic field, it will then change the magnetic field and induce voltage causing current. The flow of current then acts a signal for the light to change!  

 




 Connections to the real world…This section, I was able to connect many things to the everyday world! That’s what physics is about, isn’t it? One major thing that I learned was how security metal detectors work at the airport. I learned that they work, because throughout them, there is a coil of wire that carries a current in its own magnetic field, so when someone walks through the detector and is carrying metal, they change the magnetic field which induces voltage causing current to make a beeping noise to alert the TSA workers. Another thing that we actually took a field trip on that is a connection to the real world is how stoplights work, and it is actually very similar to how the metal detectors at the airport work. There are coils in the ground and your car acts as a magnet and changes the magnetic field in the coils, which therefore induces voltage and causes current acting as a signal for the light to change.

 


Problem solving skills….This section has not dealt with problem solving skills very much, but when working with transformers I was able to put my skills to work. By using the equations P=IV which means that for transformers the current of the primary times the voltage of the primary will equal the current of the secondary times the voltage of the secondary, so with this I am able to use the equation that states that the amount of voltage of the primary coil over the amount of turns in the primary coil is equal to the amount of voltage of the secondary of the turns of the secondary, so reverting back to Newton’s 3^rd law, every action has an equal and opposite reaction.

What I found difficult…This section, a concept that I felt was hard for me to grasp was how transformers work. I learned that transformers have coils of wire next to each other, where the primary has a lot of turns and the secondary has less turns, and the amount of turns is proportional to the voltage, so because there are less turns normally in the second than the primary, the voltage will be decreased, it that is your use for the transformer. The current running from the wall is alternative current, or ac which means that the voltage is constantly changing directions, and thereby changing the magnetic field and inducing voltage, creating current. The secondary’s magnetic field will change because of the change in the first’s magnetic field, and allow the transformer to work . It took some time for me to understand transformers, but after going over them with Ms. Lawrence, the subject was cleared up! Then, Going along with motors, it was difficult to see the differences between a generator and a motor. I then learned that a generators input was mechanical, while its output was electrical and made to work when the change in the magnetic field induced a voltage and caused a current, allowing the generator to work, but that a motors input was electrical, and it’s output was mechanical, and worked when the current carrying wire felt a force in a magnetic field. They really are two different things!