Ohm's Law, Circuits, Potential Energy difference and more!

Physics Review Blog

What I learned about….

In this section we started by learning about Charge. We learned that opposite charges attract and like charges repel. I then learned that electrons could be transferred in 2 different ways; direct contact and induction. To understand this way that charges work, we worked out some problems including why clothes stick together after being the dryer together. I found out that this happens because the clothes steal electrons from each other through friction, and some will be attracted to each other and stick. We then went on to learning about how lightning works, and induction. Induction happens when an object becomes charged without contact. Lightning is charged by induction and happens when clouds become negative through friction and polarizes them and they become polarized so that the negative clouds become attracted to the positive ground. Then the electrons attempts to find a path to the ground and once it is found, the energy will be released as thunder and lightning. Within this time, I learned about electricity and electric fields, which is the area in which a force can be felt. Electric potential is also the same thing as a volt. I then went on to learn about electric potential energy, which is stored to do work, and there must be a difference between the two to have current flow.

This encompasses ohm’s law, which states that I=V/R

Current and resistance are inversely proportional to each other.  In order to alter resistance, we learned some rules including           

-Increasing temperature increases resistance

-Increasing length increases resistance

-Altering the type of metal alters the resistance

-Increasing thickness decreases resistance

Then, we learned about circuits! During our lab we learned that when something is wired in series then, as bulbs are added on to the circuit, the length will add resistance and the bulbs will become dimmer, while if a circuit is wired in parallel, then the resistance will decrease and actually allow more energy to flow through the bulbs, and they will be brighter. We learned that homes and buildings are best wired in parallel because it protects the entire house from power going out because it isolates each circuit. Our lab encompassed some of what we had learned about circuits when we answered the question “Why does the circuit breaker in Lawrence often trip when the girls are getting ready for prom?” The answer to this question is the over use of the current will decrease from the resistance increasing making the current less able to flow because of the demand and so the circuit will become overwhelmed, and through the use of the fuse, the circuit will be shut off to prevent a fire.

What I found difficult…

This section, I feel as though we covered many different areas of physics, from basic electron behavior, to why lightning occurs, we had a broad section, but I learned a lot! One of the most challenging sections was when we learned about was polarization and induction. At first, these concepts did not make very much sense to me because I saw them as two very similar concepts. Then, after learning that Induction is when you bring a charged object near a conducting surface, the electrons inside the surface material will begin to move, and either be attracted or repelled by the object. Polarization is different because it is when one side of an atom becomes more negative or positive than the opposite side, causing charges to be attracted or repelled. Another question that was challenging to me was did the questions have to do with Electric voltage and the van de Graff generator. I learned that a van de Graff generator, although it has over 100,000 volts has low potential energy so a 120-volt outlet has a higher electric potential energy making the van de Graff machine less dangerous. Also we know that v=electric potential energy/charge, so you can have a high voltage object with low potential energy, which is what can flow through you and actually hurt you, so the Potential energy level is extremely important.

Problem Solving Skills…

My problem solving skills have definitely improved this section. When we learned the equations P=IV and I=V/R, I started having to identify the information given to me and plug it in to the equation in order to solve. I am now more confident in being able to solve equations, especially having to do with power and resistance because of this unit. During our labs, we experimented with light bulbs and circuits, which I found to improve my problem solving skills because getting each circuit to complete was similar to solving a puzzle, and when learning about series and parallel wires, the process got even more difficult, but I was able to work through all problems to find the working circuit.

Connections to everyday life…

This section I was able to connect many things that we learned to my every day life! One aspect was learning about circuits and how they work especially in homes, because before we learned about power and circuits I did not really know much about energy or direct and alternating currents. I learned that most houses are wired in AC and also they are wired in a parallel circuit, which means that the circuit can still be completed even if a bulb or outlet goes out while in series circuits, the entire circuit will break if one bulb goes out. Then we learned about fuses and why we have them! Fuses are used to regulate the current flowing through a circuit, and if the circuit becomes overwhelmed with current, the fuse will break and stop the circuit, potentially stopping an electric fire.