Electrical Wires

Electrical wires are an everyday thing, but after studying electrostatics, I am now able to better explain how they work. These are some of the wires that power my TV, DVD player, etc. Obviously, in order to power electrical devises, a charge must be carried to them. To do this, a conductor such as the copper in an electrical cord, is needed to allow the charge to flow from the outlet to the TV. The cords must be capable of handling enough current to power the TV without shorting the circuit, as happens with an overload of current.

As a little kid, whenever I unplugged something, I was always told to pull the cord out of the socket by pulling on the plastic part. This was because the plastic covering on the electrical cord "insulates" the cord and stops the charge from flowing from the copper to my hand or any other substance, and keeps people safe from electric shock.

If you have ever seen an electric shock, lightning, or some kind of electric spark, it can also be explained with electrostatics. The visible transfer of charge results in the "spark" or lightning that we see in such energy transfers. Such visible transfers are simply made by an extreme change in the electric potential of a system where a large number of charged particles are transferred to an area with less charged particles such as the ground, a lightning rod, the air, and even a person's hand. I have had many personal experiences with lightning and it is amazing to think that the enormous lightning bolt that flashes through the sky is really made up of a lot of, singularly invisible, charges.

Staticky Hair

Many times, especially during the winter, you will find your hair standing on end due to "static electricity". Even though we usually associate this phenomenon with rubbing a balloon on your head to create static, I have found that this also occurs on airplanes or while wearing a winter hat. Often when moving after leaning back on an airplane headrest or taking off a winter hat, my hair will stick to the previously mentioned surface. This is due to the opposite charges of my hair and the object. When two objects are rubbed together, they can become charged as electrons move from one object to the other. In the situation with hair, electrons probably move out of the chair or hat, making it positively charged with excess protons, and into my hair giving it an excess of electrons and making it negatively charged. Since the two objects are then oppositely charged, they attract, sticking together as I try to pull them apart. Throughout this process, charged is conserved as electrons are transferred between objects and not lost.

FRC Robotics Prototypes

Yesterday we spent six hours at robotics working on prototypes for our new robot. I spent my time on the kicker team working to build a kicker where we could vary the force and therefore the distance that it kicked a soccer ball. We managed to kick 34 feet! This involved a lot of physics, so much so that we had to borrow a force sensor from Doc. (Thanks Doc!) Our robot kicker is a "foot" attached to a "leg" with holes in it with rubber tubing strung through it. When we tighten the rubber tubes and then pull the foot back, the potential energy in the foot is great, so that when we released the foot it sprung forward and kicked the ball. After we got this prototype working, our coach asked us to find out how much force we needed to apply for each distance the ball was kicked (for later programming use I believe). So we borrowed a force sensor and attached it to the tubing. We had already figured out that the more strands of tube we used, the more force, and therefore the further the ball traveled. This means that force and displacement are directly related, therefore the spring constant equation applied (Force = K x displacement). So with the force sensor attached, our kicker team kicked the ball using the four different amounts of tubing, measured the distance the ball traveled and the force of the tube, then collected the data for the spring constant.

We also discovered that the robot kicks with projectile motion, and we kicked the ball over a 18(ish) inch obstacle that was 25 feet away. If we say that the ball went about 1.5 meters in the air after each kick then we can use kinematics (deltaY=Vvi T+.5Ay T^2) to find that it takes .55 seconds to reach the ground 34 feet (10.36 meters)away. Therefore we can use (X=ViT) to find that the initial velocity of the ball is 18.8 meters/seconds.

The Refrigerator

Surprisingly, a refrigerator can be considered a heat engine. This statement almost sounds like a paradox, but no, a fridge is actually a heat engine that does negative work. A heat engine is a system where heat is transferred into a "tank" where the pressure caused an increase in volume which pushes a piston up, causing it do work (force times displacement). in conventional heat engines such as those in cars, the system does positive work as more heat enters the system as leaves (work =Qin- Qout). In a refrigerator negative work is done as more heat flows out than in causing the piston to move in a direction that opposes the force (Qin-Qout=negative). Work is also equal to Q-deltaU so if Qnet is negative Work is negative, the system cools, and a refrigerator is formed. I think it is pretty cool that a heat engine and refrigerator work the same way, just opposite. A car engine and refrigerator both do work but one is positive and the other is negative.

Hot, Flat, and Crowded

The novel Hot, Flat, and Crowded by Thomas Friedman is a very intriguing and thought provoking book that I thoroughly enjoyed reading. This book is an “eye-opener” as it tells how if we, in this generation, do not do anything to care for the environment and make the planet more green, the earth will be near unlivable due to population growth and temperature increase by as early as 2050, well within our lifetime.

This novel is fascinating as it tells about the nature of people and why we need to change in order to help the planet. Friedman explains that people are only interested in what will easily make them money or in what will directly affect them in the near future. However, in order to save the planet for future generations, people now have to make sacrifices. I completely agree with this analysis and think that the government and governments around the world, especially in fast growing countries like China, need to impose laws with environmental standards such as gas and coal taxes, as this book suggests.

I believe that this book makes many good points about the United States and I agree that we need to set an example for the world by “going green”. I concur that if we do this by reducing our reliance on oil, we will not only increase our efficiency and ingenuity, but will also become a more independent nation.

I enjoyed Friedman’s view of the future with the “Smart Black Box”, and I think that if everyone in the world cooperates we can achieve a similar situation in a matter of years. I agree with his proposition that this would require the education of people in many countries on the ways of energy efficiency, which would not only increase the standard of living around the world, but would help to improve environmental conditions by raising awareness. I think that these ideas are essential to the world and implementing them is going to be the only way of protecting the earth for years to come.

I believe that this book truly represents the world today as well as what we should strive for it to be in the future. This book has a very important message and should be read by everyone.