Ch20_Demberro_Last2Parts

=Part 3=

Read and Summarize Lesson 2
Part 1 What is an electric circuit? An electric circuit is a closed loop where charges pass through continuously. They will travel from high electric potential to lower electric potential.

Part 2 What are the requirements of a circuit? The requirements are as follows: a) Must be a closed loop, no openings. b) Must have an energy supplies with high and low potential ends. c) Must consist of all conducting materials, no insulators.

Part 3 How is electric current measured? The equation is. By this equation, you can tell that it will be one coulomb divided by one second, which makes sense given the definition of current in the guiding questions. C/s is better known as an ampere denoted by "A".

Part 4 What is power when it comes to electric charges? Power is similar to what it was like when it dealt with mechanical energy. It states the rate, in terms of time, that the charges are supplying a circuit or taking on a load. It is most commonly equated to being voltage times current.

Part 5 What are corrections to common misconceptions regarding electric currents? 1. Batteries are NOT rechargable. 2. Electrochemical cells are not source of charge, electrons are already there. 3. Charges are free-flowing and will not be used up. 4. In comparison, charges move slowly than one would assume.

Conclusion Circuit need to be completely closed in order to actually have a current. This leads to electric charges flowing throughout the circuit, with the battery supplying the power for the whole circuit. People have misconceptions about how this works, in reality, battery just allows the difference in voltage to start the flows and wear out when the voltage dwindles from resistance.

Read and Summarize Lesson 3
Part 1 What shall be the journey of a typical electron? While on the path to lower potential from high, electrons typically hit into atoms and collide, deviating their paths. Just as they lose minor voltage when hitting against other things, they lose the most when going through light bulbs and resistors as they drop much lower than before. This chart and picture help explain it well. Part 2 What is resistance? Resistance is the hindrance of electrons that flow through a circuit. It is measured in ohms, Ω, and each material has a resistivity, conductors have very small ones, while insulators' are large, which is directly related to how much they can/will resist. The equation is where p is resistivity, L is length, and A is area of cross-section in part discussing.

Part 3 What is Ohm's Law? Ohm's Law is defined as how voltage, current, and resistance affect each other, the equation is V=IR, where V is voltage, I is current, and R is resistance. It is one of the most important laws in science. Part 4 What are other ways at looking at power in circuits? Power can also be calculated by having P=V 2 /R or I 2 * R. This is done by using simple algebra.

Ohm's Law
Objective: Hypothesis I believe that the experiment will show that pressure difference and flow rate have a direct relationship since V=IR according to Ohm's Law. Also, I believe Ohmic materials will follow Ohm's Law and Non-Ohmic ones will not since there has to be a logic reason that a material could be either Ohmic or Non-Ohmic.
 * What is the relationship between Pressure Difference and Flow Rate?
 * What is the difference between Ohmic and Non-Ohmic materials?

Procedure: Measure the voltage and flow rate of different resistors and bulbs using the setup exemplified below. Data: Sample Calculations: Graphs: Analysis: The above graphs show the relationships between voltage, flow rate, and resistance. For the two linear graphs, our resistors, the slopes are linear, showing they are Ohmic materials, their slopes are equal to the resistance, as shown by the equation under "Sample Calculations" such that R=V/I. The slope all the way on the left looks vertical because the resistor was so big compared to the others that its slope is very large. Looking at the two curved graphs, those of the bulbs, it is apparent that they are non-Ohmic since they have non-linear slopes. Thus, they will not follow the law of R=V/I, as their slope is not constant.

Discussion: Conclusion: My hypothesis was correct. The data shows that the resistance was equal to the pressure difference divided by the flow rate, and the corresponding graphs prove that resistance does equal voltage divided by flow rate due to the linear shape of the resistors. Also, it was proven that non-Ohmic materials do not follow Ohm's Law because the bulbs, which are non-Ohmic lacked linear slopes, proving that they did not follow the law. The error was not too bad on the resistors, and given the fact that the resistors have a range shows that our results for them were pretty solid, ranging from 0% to 14.39%. However, the bulbs were not very accurate, shown by the error reaching as high as 89%. This stems from the fact that we could not be certain of the exact resistance of the bulbs, we only assumed 10 and 60 ohms. Also, the device could not always be accurate or give the proper decimal place, which would throw our results off even further. A more accurate device would make the experiment run smoother. What we did is important since it will be able to better explain what goes on in a circuit and allow us to more easily figure out resistance, flow rates, and electric potentials of materials in a circuit.

Kirchhoff's Rules Lab Purpose: Determine how currents split in multi-loop circuits. Hypothesis: In a multi-loop circuit, the current will decrease each time there is a split as the original current must go to two different wires. Flow rate will overall increase to compensate for all the paths it must travel. Procedure: 1. At one of the four set-up circuits, correctly draw its schematic diagram, including batteries, resistors, and junction points. 2. Mark down resistance of each resistance and voltage of each power source (already given). 3. Measure and record the voltage by placing the multimeter parallel to to resistor or power source that needs to be measured. Be sure to set the multimeter so it has the most significant figures possible. 4. Measure and record the current by placing multimeter along series to resistor or power source that needs to be measured. Be sure to set the multimeter so it has the most significant figures possible. 5. Using Kirchoff's Rules, determine how the current split in each diagram. Circuit A Circuit B Circuit C Circuit D Data: (Volts) || Current (milliAmps) || Resistance (Ohms) || (Volts) || Current (milliAmps) || Resistance (Ohms) || Sample Calculations: Circuit D with currents depicted Solving for currents assuming voltages and resistances are correct Solving for voltage with given resistors and calculated currents above. Circuit A Circuit B Circuit C Analysis: (For Circuit D, Current 1)
 * || Voltage (Volts) || Current (milliAmps) || Resistance (Ohms) ||
 * R1 || 3.96 || 12.9 || 300 ||
 * R2 || 2.39 || 7.8 || 300 ||
 * R3 || 2.05 || 20.6 || 100 ||
 * R4 || 1.54 || 15.7 || 100 ||
 * R5 || 4.46 || 8.0 || 560 ||
 * B1 || 6.08 || 22.0 ||  ||
 * || Voltage(Volts) || Current(milliAmps) || Resistance(Ohms) ||
 * R1 || 3.84 || 7.7 || 500 ||
 * R2 || 1.17 || 1.5 || 750 ||
 * R3 || 6.14 || 6.2 || 1000 ||
 * B1 || 10.03 || 7.7 ||  ||
 * B2 || 5.00 || 1.5 ||  ||
 * || Voltage
 * R1 || 9.20 || 9.6 || 1000 ||
 * R2 || .48 || 0.6 || 820 ||
 * R3 || 5.50 || 7.9 || 680 ||
 * R4 || .54 || 0.9 || 560 ||
 * B1 || 5.03 || 8.0 ||  ||
 * B2 || 9.99 || 9.6 ||  ||
 * || Voltage
 * R1 || 4.87 || 45.0 || 100 ||
 * R2 || 1.97 || 9.4 || 200 ||
 * R3 || 1.67 || 34.9 || 47 ||
 * B1 || 1.52 || 31.4 ||  ||
 * B2 || 1.56 || 8.1 ||  ||
 * B3 || 4.50 || 39.7 ||  ||

Discussion:

Conclusion: My hypothesis was correct, as each time the current would divide, it would equal the two currents at the junction point. For example, in Circuit D, I1 split into I2 and I3, and looking at my experimental values I1= 45mA and I2+I3=34.9+9.4=44.3 mA, which proves that the current split at the junction point. One other example is in Circuit B, when the experimental value of I1= 7.7, and the two it splits into are I2 and I3 whose sum is also 7.7 (6.5+1.2). This is shown in all the other circuits with all different types of currents, both theoretical and experimental. As shown in the analysis, besides Circuit A, all my theoretical results were very accurate towards my experimental values, and all the circuits, including Circuit A, showed that each result differed by the same margin. The error of this lab could come from a few different places. First, we assumed that the multimeter and battery/source charges, had no resistance, yet in reality, they have a little resistance, and depending on the use of them, they could have a fairly significant impact on deviating the results. Furthermore, the resistors have areas of numbers, not an exact value, and we just took the ohms of the resistors at face value. To change the lab for the better, we could have had more accurate equipment or measured for the battery's internal resistance to take that into account. This lab is valuable since it shows the application of Kirchoff's Rules. This could come in handy when determining how much current will go to appliances in a home when lined up parallel, so the electrician can more easily determine the brightness of lights and how flow rates will differ. Also, it gives examples of the rule emf can play in a circuit. FInally, it gives us the ability to find values of even the most complicated circuits.