AC/DC Circuits!

As our last unit, we learned about electricity, specifically DC circuits. DC circuits are electrical circuits that keep electrons in a direct and constant flow if the circuit is closed. Batteries are used to power these circuits. The current of the circuits is like the flow rate in plumbing pipes, the voltage is like the water pressure, and the resistance in each bulb is like the size of the pipe (friction, essentially).

This is a diagram of a DC circuit in series. In this circuit, the energy created by the batteries allow the electrons to flow through the circuit. The bulbs are dimmer than normal because the voltage is split between the two bulbs from the batteries. The current remains the same throughout because there is nowhere for it to split.The circuit is just one loop so the current stays constant even when the voltage changes due to the resistors. This is a series circuit because the electrons have only one "series" of wire to travel through. If one of them were to be removed, neither bulb would work because the bulb serves as a connection. The resistance of each bulb is like a friction that slows down the current and since it is in one series of wire, the current is slowed through the whole thing.

This is a diagram of a parallel DC circuit. This circuit is different because there are two paths for the electrons to flow. Unlike the first one, if one bulb is removed, the other one will not be affected because electrons still have a way to flow through the other one. The current isn't affected by the resistance of each individual bulb because the electrons come back together after they go through each individual bulb. This is why the bulbs are brighter. The voltage is like what water pressure would be in some plumbing pipes. Since there is a fork in the path, the water pressure remains the same, and then after it goes through the "friction" of the resistors, it just comes back together. The resistance of the bulbs does not play a huge role here because since there are two paths, the current doesn't affect each bulb.

Finally, we have a complex circuit, with a bulb in a series with two bulbs that are in parallel. As you can see, the two bulbs in parallel aren't as bright as they were before. This is because the bulb in circuit creates a voltage drop like in the first diagram, therefore making the bulbs in parallel dimmer. If one of the bulbs in parallel is removed, everything still works the same. However, if the bulb in series is removed, everything stops even when the other two are in parallel. This is because if the bulb in series were removed, the circuit would be incomplete. In this circuit, the bulb in series acts the same as the first diagram for the two parallel bulbs. The "friction" in the resistor of the bulb in series slows the current down so that when it gets to the parallel circuit, the current still splits like normal, but the current is slower to begin with.

The voltage and current are different in each of these because they all have different means of transporting the energy. When they're put together, it's a mixture of both ways to solve.

2011 Sports Illustrated Log Ride: Wavy Physic's!

After hours and hours of hard labor, slaving over band-saw's and drills, we have completed our 2011 Sports Illustrated Log Ride. The boat runs through the ride smoothly, packed with tons of fun turns. I speak for us all when I say that I gained so much knowledge about physics in the real world during this project. Getting to see everything run so smoothly and just the way we wanted, and then the math involved to make it all do so, made it very easy to see the relations between the technicalities of it all and real life. Here is our presentation of the project on a Prezi, and you can take a closer look on our team site!

https://sites.google.com/a/parishepiscopal.org/physics-honors/amusement-park/team-4

Sports Illustrated Log Ride on Prezi

AAPT Photo Contest: Refraction of Regular Light

For my photo for the AAPT photo contest, I took a prism and an LED flashlight in a dark room, and used them both to create a beautiful, for the lack of a better term, array of light. Since I used an LED flashlight, the prism couldn't show the different colors of waves that make up the one light (i.e. the color spectrum of a rainbow). Had the sun been out and bright enough on the day I was doing all of this, I would've been able to use the sun's light and get a broad spectrum of colors.



The different angles of the glass prism make the light reflect in different ways. The light enters the prism, going from one medium to another (air to glass) which then causes it to slow down or speed up (in the case, slow down) and refract in a different direction. The incident angle (the angle in which the light source was directed at the prism) was the reason as to why the light was refracted the way it was. If I had placed the light source lower, higher, more to the right, or more to the left, I would have gotten different outcomes. Here are pictures of the prism I used, and the outcome when I shined the LED flashlight through it.

The third photo (of the refracted light) may seem a little blurry but if you look carefully, it is not. The distortion of the light and everything just isn't perfectly clear because the light source wasn't perfectly aligned, therefore the glass on one side of the prism and the glass on the other create slightly different angled light.