Magnetism part 2

Here we dealt with the issue of two current carrying wires and the forces between them. When they flow in the same direction they attract, the opposite and they repel





Here we measured the magnetic field with different amounts of coil. It increase with the amount of coils

Placing a magnet down two separate pipes, one metallic, it took longer for it to go down the metallic one. This is because the reaction force is to oppose the cause of it.

Magnetic Motors

Today we explored more on magnets, as well as how they can be used as motors

We first viewed the difference between a magnetic pin and nonmagnetic pin. The magnetic pin has all its small molecular poles pointing in one direction, which causes a net magnetic affect. We found that heating a magnet will destroy its magnetic property.



We then wrote an equation for torque on a current loop of t = u x B. u = IA. Above we solved a sample problem involving torque.



Here is a St. Louis motor, which is run off of a normal battery, which magnetizes the wires around the center loop. This interacts with the magnets on the side and creates motion



We attempted to make our own motor, but could not get it to work. Instead we took a video of another group who made a simpler motor work.



We also saw the magnetic field around a current carrying wire

Magnetism

Here we put a compass around a magnet to view the magnetic field around one
.

To see more clearly, we saw a picture of iron fillings sprinkled around a magnet.



Here we picked three surfaces, the big one around the whole magnet, one just to the left of the top, and one at the bottom. We found the net flux = 0, which proved the fact that a magnet can not have a single pole.


Professor Mason demonstrated the Lorentz Force with a magnet and an oscilloscope. When he approached the screen the parallel, nothing happened, but it did when it was perpendicular.



Here we sent current through a wire over a magnet. It repelled and attracted, depending on the current flow. This shows that current produces a magnetic field




Here we calculated the magnetic force of a bent wire. Instead of integrating, we just used excel.

Electronics

Here we connected a phone, which was playing music, to an oscilloscope. It displayed its accompanying wave on the screen.



Here we lit up a LED light (pictured in red next to the black wire) on a breadboard connected to a power supply. The higher the voltage, the brighter the LED shined.






















We built a sound amplifier using the breadboard, the same power supply, as well as capacitors and resistors. We also used a transistor, which amplifies electronic signals. It is composed of a collector, base, and emitter. We also learned about a diode, which only allows current to flow through one direction through it.

Osciloscopes

We spent today by working with an oscilloscope, which is a device that displays voltage measurements via a beam on a screen




Here w did some calculations involving how the oscilloscope works.

We connected a speaker to a function generator (pictured above on top of the oscilloscope) to produce different sounds. The function generator is capable of generating waves of different functions. We created different sounds by changing the function, as well as the frequency



Here we did some work with the oscilloscope and wrote down our observations




Next we attached an AC transformer, as well as kept the function generator connected. We then displayed several objects on the screen


LAB: Mystery Box

We were given a box and found the unknown voltage of each color.

Capacitors

Today we learned about Capacitors, which are devices that are used to store Voltage.

Here we found that the capacitance (C) in a circuit for parallel and series is the opposite of a resistor. For series, 1/C total = the inverse of the individual resistances added. For parallel, Ctotal = the summation of all the capacitance.

Here we charged a capacitor by hooking it into a circuit with a battery. Our calculation for the capacitor voltage was close to what we measured

We then saw the relationship of current and voltage of a capacitor in a circuit. As seen by the graph, as a capacitor charges, the voltage goes up, while the current goes down. The current eventually goes to zero because the voltage between the battery and the capacitor are now the same.

The last thing we did was build our own capacitor. We Found the value for k, which is the capacitance measured over what the capacitance would be if there was vacuum between the two plates, as opposed to material

DC Circuits

Here we began our lecture on Direct current to see how voltage and current work with resistors between parallel and series circuits. We predicted the light bulb in the middle would light up dimly if it was connected in the circuit, but we were wrong, it stayed out.




Above we connected bulbs in series. We found the current is the same throughout, however the voltage drops after each interaction with a resistor in the circuit.




Above we found in parallel circuits, the current is not the same as would be in a series circuit, however the voltage is the max offered by the EMF/battery.



Here we had to figure out the resistance of resistors based on the colors of them. We then tested them to verify their resistance, which was close to what they were marketed as.

Voltage of Continuous Bodies

Today we worked with finding Voltage involving continuous bodies. Principles of Gauss's Law were used in this section.

Here we wanted to find the Voltage around a ring. We used the integral shown, and also used excel to break it into 20 pieces and sum them up, which is shown below.

Here we found the Voltage of a line with a charge density of lambda. The work above is similar to the method for Gauss's Law calculations

LAB: Voltage between, and around, two charges

We moved our Voltmeter around several places on the paper, with the two thumbtacks having a certain voltage, to measure the volts experienced at different places on the paper. The paper voltage changed at different places across the paper.

Series Vs. Parallel and Ohm's Law

Today we started off by seeing how hooking up circuits in series as opposed to parallel affect resistors in the circuit.

Hooking up resistors, light bulbs in this case, in series as opposed to parallel make a difference in the light brightness. In series, the current is the same, but the voltage is split between the two. In parallel, the current is not the same, but the voltage is the same when it reaches the bulb. This causes increased light.

Here we set up an experiment where we heated water with a heater, with a certain amount of voltage and current coming through it.

Using LoggerPro, as well as our knowledge from prior chapters involving heat energy, we calculated several values. Temperature, and alpha, a constant that is unique to different materials

Electric Potential

We started off todays lecture by trying to figure out  different ways that we can light a bulb with a battery and one wire.

We experimented with different ways to light the bulb and then drew the diagrams of what worked and what did not work.

Drawing a generic diagram for what worked, we then gave a description to the three components involved in the experiment. The battery gives energy/voltage, the bulb uses energy, displayed as light, and the wire is the material that the energy transfers through

Here we used two bulbs instead of one, which increased the brightness. The brightness was doubled, because we doubled the voltage/energy in the system

Above are different versions of an ammeter. An ammeter measures current at any point in a circuit. Simply wire it into the circuit at any point and it will give you the current at that point

Here we graphed the current vs. voltage graph. We found that the sloped was resistence. This leads to the equation V = IR.

Here we had current traveling through wires so we can see how area affected the equation V = IR

Doing experimenting, changing the area decreased the resistance experienced. This is a very important principle, that resistance is inversely proportional to cross-sectional area. If you are sending current through a wire, simply increase the cross-sectional area of the wire to decrease the resistance experienced.