Thursday, May 22, 2014

FASHION AND PHYSICS!

1) Newtons first law. Newtons first law states that objects in motion will stay in motion, and objects at rest will stay at rest, unless acted upon by an outside force. 

Therefore, despite these crazy shoes, these models will not stop walking unless somebody pushes them over, they trip, or they decide to go the other direction; all examples of outside forces. 

2) Newtons second law. Newtons second law states that mass is inversely proportional to acceleration. Therefore, objects with less mass, can go faster than objects with more mass. In fashion, stick skinny models often walk the runway. While this ideal is kind of unrealistic, and the reasoning behind it may not be physics, the models with less mass can certainly walk the runway faster. 
Because this model has a very low mass, she can most likely move faster. 

3) Newtons 3rd law. Newtons third law states that for every action, there is an opposite and equal reaction. Because of this, if two runway models walked directly into each other, they would be exerting an equal amount of force during their collision. However, this does not mean that they have to have equal masses or accelerations. Rather, just the sum of their mass and acceleration must equal. 
 f=ma. 
f=Ma
f=mA
These two models exerted the same amount of force on each other when they collided. We know this because of newtons third law.

4) Washing Clothes. When we wash the clothes that we buy, many physics concepts can be applied. Clothes are trying to go straight (inertia) while the machine is going in a circle, causing the clothes to smack the sides therefore water is getting smacked out of them through the holes. Centripetal force acts on the clothes and they are forced in a circular path, but the water is not. 

5) Balance. When walking the runway, it is very easy for models to fall over, because it is very easy for them to lose their balance. This is because with their legs very close together, and their tall height when they walk, their center of gravity can easily fall out of the perimeters of their base of support. 

6) Backpacks. Why do we always have to bend over when we wear backpacks? This, like number 5, also relates to balance. By adding a backpack, you are adding more mass to yourself. Subsequently, your center of mass shifts. In order to stay balanced, and keep your center of gravity above your base of support, you have to lean forward. 

7) Why do pants need to be made so your legs can bend? Obviously, for us to walk. However, why do we have to bend our legs in oder to go fast? 

When you bend your legs, you are bringing your mass closer to your axis of rotation, therefore making it easier to spin, and go faster. 

8) Kinetic and Potential energy. Before a model walks (and is standing still) she has potential energy. However, when she starts moving, it is transformed into kinetic energy. When she stops again, it is back to potential energy. Potential and kinetic energy are central concepts that we learned in physics this year, as kinetic energy is basically the energy something has when it is moving. 

9) Work. Work is present when both the distance and force are parallel. In the chanel fashion show, they used a grocery store theme. As the grocery cart was pushed down aisle, both force and distance are parallel. Therefore, work is done. 

10) friction. Shoes are often made so that they can conduct a lot of friction with the ground. This is done so that people do not fall, and can formulate effective traction with the ground. 

Additionally, magnets! magnetic earrings? Magnetic nail polish? Physics relates to everything!








Tuesday, May 20, 2014

Wind Turbine Blog

Background: 
Wind turbines are used to convert energy from the wind into mechanical energy, and then into electrical energy. The wind turns the repellers which creates mechanical energy. This becomes the input for a generator. This process is exemplified through rotating the magnets around the coils of wire. This process causes a change in the magnetic field. This induces a voltage in the wire which creates electrical current. 

Materials:
-PVC pipes
-cardboard 
-coil of wire
-3 small round wooden pieces
-wooden rods
-magnets
-wooden box cutout.

Uses:
The PVC pipes were used as the body of our turbine, and also as the base of our turbine. Additionally, we used smaller pipes to put the actual generator inside. We made the repellers out of cardboard, and hot glued them to the rest of our turbine, to allow them to spin correctly. Inside the PVC pipe, we kept the generator. This generator was made with 2 small round wooden pieces. Glued to these, were 4 magnets. The north side of two of the magnets was facing out, while the south side of the other two was facing out. This allowed the generator to function. We attached this to a long narrow wooden pole, and stuck it out one of the sides of the PVC pipe through drilling a hole. This was difficult, because we had to use a wooden box cutout to make a small circle, so that the wooden rod would not move around too much. We got coils of wire and hot glued them to the sides of the PVC pipe to induce voltage. We used a small wooden circle to attach the the outside of the wooden rod, so we could glue the repellers onto it, and our turbine could function. 

Results/discussion:
Well, despite the efforts from the Wyatt, Carson, Will trio, our results were slightly on the side of disastrous. Unfortunately, we only generated .1 volts of power, and did not have time to improve this. However, this was caused because of our repellers. They were very weak, had hardly no support, and barely even moved. Everything else on our turbine was perfectly functioning. This was our first and last try therefore the repellers are the only thing that I can advise working on. 


Sunday, May 11, 2014

Unit Blog Reflection

MAGNETISM 

In this section, we learned about magnetism. This includes many interesting aspects for example what causes the northern lights, how credit card machines work, and many other topics. 

Basics of Magnets.
Moving charges are the source of all magnetism. All magnets have a north and south pole, and the field lines run north to south inside, and outside, south to north. If you cut a magnet in half, it too will form a north and south pole. The earth also has a geographical north and south pole along with a magnetic field with a north and south pole. Domains are clusters of electrons moving in different directions. When domains are aligned, they form north and south poles. Like poles of a magnet repel, and opposite poles attract. 





Compasses
The compass is a little magnet that can spin freely. The north end of the magnet attracts to the south end of the earth, while the south end of the magnet, attracts to the north end of the earth. This attraction causes the needle to align with the earth's magnetic fields. The north pole of the compass points to the correct geographic north because the earth's geographical poles differ from the earths magnetic poles.

How Can a paper clip become a magnet?
Originally, the paper clip is not magnetized. The domains within the paperclip are all moving in random directions. However, when a magnet is held up to the paper clip, the domains align, forming north and south poles. These north and south poles are attracted to other north and south poles, thus becoming a magnet. 

Cosmic Rays
Cosmic rays enter the earth through the poles rather than the equator. This is because the force felt through the magnetic field of the earth, causes the rays to spiral around the equator into the poles. The poles run parallel to the rays, where as the equator runs perpendicular. The northern lights are caused by these cosmic rays entering. 

Electromagnetic Induction
Out of everything that we have studied in this unit, I think that I struggle most with electromagnetic induction. Induction being a concept I had to wrestle a lot with last unit, it was difficult to see it again in an even more complex way. Electromagnetic induction is a way to increase voltage by changing the magnetic field in loops of wire. The change between a magnetic field and loops of wire, is what induces voltage. The more loops in a magnetic field, the more voltage, subsequently, the more resistance. When the magnet is inserted through or around the loops, there is a change in the magnetic field of the loops. The induced voltage also makes a current. The change in magnetic field also induces the current. The amount of current produced in electromagnetic induction depends on induced voltage, the resistance of the coil and the circuit, and the change in current in a nearby loop. 

ApplicationIn the pavement, there is a loop of wire. When the car, which is magnetic, moves over the wire, it changes the magnetic field of the loop. This change in the magnetic field induces voltage, which causes a current. This current is a signal to the stoplight to change. Metal detectors and credit card machines undergo a similar process.

Generators
If you continuously change the magnetic field, that is how a generator works. Through electromagnetic induction, generators turn mechanical energy into electrical energy. (Mechanical energy is a magnet that moves, whereas electrical energy is current in a wire. 
Generators use resources such as wind or water to turn loops of wire inside of a magnet. It relies on the change in the magnetic field rather than the force of the magnetic field. This change in the magnetic field induces voltage which causes current, which is the current we tend to use in our households

Motors
Motors are similar to generators, but Motors transform electrical energy into mechanical energy.  Moving charged particles feel a force when moving perpendicular to a magnetic field. The force felt by the wire causes a torque. Motors work from the force of the magnetic field. Motors can be used for things like cars. Basically, a current runs through a coil, which feels a force because it is within a magnetic field (moving charges feel a force in a magnetic field). This causes the coil to spin, producing usable mechanical energy. 


Transformers
A transformer is a device used for increasing or decreasing voltage or transferring electric power from one coil of wire to another through electromagnetic induction. A transformer is made up of two coils of wire. One wire is a primary coil, and the other is a secondary. The primary is is directly connected to the power source. Therefore, the primary is the input, the secondary is the output. Whenever the primary switch is open or closed, voltage is induced into the secondary current. AC current runs through the primary, which causes a change in magnetic field. DC cannot be used, because the current it produces only goes in one direction. The more turns in the wire, the more voltage is produced. If the secondary has more turns the primary it will produce more voltage than the primary and the voltage will said to be stepped up. If the secondary has less turns than the primary it will produce less voltage than the primary and the voltage will said to be stepped down.

FORMULAS
power in = power out
primary power/primary turns=secondary power/secondary turns
power=voltage x current
IV=IV
Vi=vI
ENERGY ALWAYS REMAINS CONSTANT

To conclude...
The area that I struggled most in, was electromagnetic induction. As I mentioned before, I had trouble with the concept last unit, and as it occurred in this unit also, it became even more complicated. I overcame this by looking at different people's blogs and talking to Mr. Rue for extra help. Additionally, I had issues with transformers, but I got over this by also looking at blogs and seeking extra help. 

Thursday, May 1, 2014

Motor Blog

Here is a picture of a typical battery powered motor. To make our motor, Will, Wyatt, and I used a piece of wood, a battery, magnets, paper clips, tape, a rubber band, and a coil of wire. We began by attaching the battery to the piece of wood with tape. We then formed hooks with paper clips, and attached them to the ends of the battery. We made the wire into a small loop with two tails in order to allow it to hang between the paper clips. We then placed the magnets on the battery.

reason for battery: supplies voltage and current
reason for coiled wire: provides a pathway for current to flow. Coil=thicker wire/ more wire= more possibility for current to flow, more power. 
reason for paper clips: connects wire to battery, completes the circuit
reason for magnet: attraction makes the loop of coil turn creating a magnetic field

Armature 
In order to allow our motor to function correctly, we had to scrape off one side of the coil. This let current flow throughout the circuit. We only scraped off one side because if we scraped all around, current would want to flow in both directions. We then attached the wire to the paper clip to allow the flow of current. 

Why does the motor turn? 
The magnetic field is the reason the motor is able to function. The force of the magnet is charged by the battery which is perpendicular to the motor. This creates force. The magnet causes a magnetic field, therefore charges move in one direction, causing the motor to rotate. It is able to turn because the force is in one direction. Again, we scraped off the sides of one end of the coil, because if force was going in both directions, the motor would not be able to function.