Ch20+Part+2_RabinR

=Chapter 20: Resistance (Part 2)= toc

Investigation 1
What effect does the type of bulb have on a capacitor during charging and discharging? HYPOTHESIS: The round bulbs and long bulbs each have a different resistance and therefore will have different affects on a capacitor during charging and discharging. SAMPLE DATA: Charging through round bulbs, Discharging through long bulbs media type="file" key="Investiation 1 - A.mov" width="300" height="300" Charging through round bulbs, Discharging through the Genecon media type="file" key="Investiation 1 - A.mov" width="300" height="300" CONCLUSION: My hypothesis was correct! As seen in the sample data, there is a clear difference in effect on capacitors based on the type of bulbs used. It can be seen that the round bulbs light for a brief period of time in comparison to the long bulbs. This can be explained by the resistance of each bulb. Round bulbs have less resistance than long bulbs and therefore the charge flows through the circuit much faster.

Investigation 2
What are the differences between the filaments or round and long bulbs? (Use a microscope.) HYPOTHESIS: The filament of a round bulb will be wider and shorter while the filament of a long bulb will be longer and thinner. SAMPLE PICTURES: **Observations seen through microscope, data pictures taken from online source Round Bulb Long Bulb CONCLUSION: My hypothesis was correct! It can be seen through the pictures above that there is a clear difference in shape between each bulb. The round bulb is much wider and shorter while the long bulb is much longer and thinner.

DEFINE AND EXPLAIN
How is air moving through straws analogous to charge moving through a filament? Air moving through straws is analogous to change moving through a filament due to its depiction of resistance. When using a straw that is long and thin, it is very difficult to blow through. However, when using a straw that is short and wide, it is very easy to blow through. The longer straw thus has much more resistance than the shorter straw. This supports the idea proven in investigation 1 that the long bulb has more resistance than the round bulb and can now be proven to be because of each's shape.

DEFINE AND EXPLAIN
What is the difference between flow rate and flow speed? Flow rate is the amount of charge passing through a specific point of the circuit during a specific time. If the point of the circuit has high resistance than the flow rate will be rather small because with greater resistance there is less room for charge to occupy. If the point of the circuit has low resistance than the flow rate will be rather large because with smaller resistance there is more room for charge to occupy. Flow speed is the actual velocity the charge moves throughout the circuit. Flow rate and flow speed have no affect on each other.

Investigation 3
How does the number of bulbs in a single loop affect the overall current and resistance in a circuit? HYPOTHESIS: The number of bulbs in a single loop will not affect the overall current and resistance in a circuit. SAMPLE DATA: Circuit A media type="file" key="Investigation 2 - A.mov" width="300" height="300" Circuit B media type="file" key="Investigation 2 - B.mov" width="300" height="300" Circuit C media type="file" key="Investigation 2 - C.mov" width="300" height="300" CONCLUSION: My hypothesis was correct. In circuits A, B and C the compass deflected approximately the same distance and therefore the number of bulbs in the loop did not affect the overall current and resistance in the circuit. If the compass were to deflect different distances then the current and resistance would have changed.

Practice Set 1
Resistance



Reading 1
Pressure Difference

Practice Set 2
Color Coding

Investigation 4
How does the number of bulbs side-by-side affect the overall current and resistance in a circuit? HYPOTHESIS: The number of bulbs side-by-side will not affect the overall current and resistance in a circuit

SAMPLE DATA: //Class demonstration// Brightness || Compass Deflection || CONCLUSION: My hypothesis was correct. The number of bulbs side-by-side did not affect the overall current and resistance in a circuit. This is because during the class demonstration neither the brightness of the bulb or the compass deflection changed between each circuit. Due to the parallel formation, the bulbs are all connected to both the positive and negative sides of the battery and thus receive the same amount of charge.
 * Circuit || Bulb
 * 1 || no change || no change ||
 * 2 || no change || no change ||
 * 3 || no change || no change ||

Investigation 5
Does adding wires in series or in parallel affect the overall resistance of the circuit? HYPOTHESIS: Adding wires in series or in parallel circuits will not affect the overall resistance of the circuit. SAMPLE DATA: //Class demonstration// Brightness || Compass Deflection || CONCLUSION: My hypothesis was correct when dealing with series circuits however, not parallel circuits. As seen in circuit B (series circuits), 3 wires were used instead of 1 and both the bulb brightness and compass deflection did not change and therefore the overall resistance did not change either. A wire has an insignificant amount of resistance and therefore has no affect on the circuit as long as the original closed loop has not changed. In circuit C, however there was a larger deflection and only one bulb remained lit and thus there was less resistance.
 * Circuit || Bulb
 * A || control brightness || control deflection ||
 * B || same as A || same as A ||
 * C || bigger deflection || the bulb that is short circuited goes out while the other stays on ||

Investigation 6
What effect do dueling battery packs have on bulb lighting and flow rate? HYPOTHESIS: Dueling battery packs will have an effect on bulb lighting and flow rate depending on the placement in the circuit as well as the type of circuit it lies in. In a series circuit there will be more resistance however in a parallel circuit there will be no effect. SAMPLE DATA: //Class demonstration// CONCLUSION: My hypothesis was correct. Dueling battery packs in a series circuits caused more resistance and thus the bulbs became dimmer and dimmer until there was no light. This is because the dueling battery packs oppose each other and weaken the light. In circuit D the opposing battery pack was equal to the original battery pack so the lights went completely. In the parallel circuits, there was no affect on the bulbs and there was no affect on resistance or flow rate.
 * Circuit || Observations ||
 * A || Brightly lit ||
 * B || Dimmer than circuit A ||
 * C || Dimmer than circuit B ||
 * D || No light ||
 * I observed no change when battery packs were added to the parallel circuits (Circuits E, F, G)

Practice Set 3
Battery Structure

Investigation 7
How does mixing bulbs in series affect flow rate and pressure in each part of the circuit? HYPOTHESIS: Mixing bulbs in series will cause flow rate and pressure to take the form of the more resistance bulb. In this case the long bulb is more resistant than the round bulb and only the long bulb will light. SAMPLE DATA: With the above set-up, only the long bulb lit. CONCLUSION: My hypothesis was correct. When mixing a long bulb and round bulb in a series together, only the long bulb will light. The long bulb is the more resistant bulb and the circuit will take the flow rate and pressure of this bulb. The flow rate has decreased and the round bulb can no longer light.

Reading 2
Mixing Bulbs

Investigation 8
What is the effect of adding another round bulb in parallel? Set up the 3-bulb circuit in figure on the left, with a gap for a 4th bulb to be added. then add the 4th bulb to form the circuit in figure on the right. To switch back and forth between the two circuits, you can add the 4th bulb and its socket, and simply unscrew the 4th bulb to break the connection. HYPOTHESIS: Adding another bulb in parallel flow rate increases in the circuit causing all the bulbs to get brighter. SAMPLE DATA: The outer bulbs (those displayed on the top and bottom of diagrams) become brighter while the other bulbs dim. CONCLUSION: My hypothesis was incorrect! Although but adding this bulb parallel increases the flow rate, all of the bulbs do not get brighter. The only bulbs that get brighter are the top and bottom ones while the other two dim. Because they are parallel they have charge split up amongst each which makes them dimmer then the others.

Investigation 9
How does the addition of another branch affect flow rate and pressure in the wires? Assemble a circuit with a 3-cell battery and a round and long bulb in series. Using a compass, measure the flow rate in wires A and B. Add a branch with a second long bulb parallel to the long bulb, but don't make the connection. Predict what will happen to the bulb brightness and flow rate when the connection is made. Repeat for a round bulb and for a connecting wire. HYPOTHESIS: The addition of another branch increases the flow rate and pressure in the wires. SAMPLE DATA: Lighting || Compass Deflection || long - dim || deflects more than A || long - go out || deflects more than B ||
 * Circuit || Bulb
 * 1 || all light || deflects ||
 * 2 || round - light
 * 3 || round - light

CONCLUSION: My hypothesis was correct. When the branches of low resistance are added the current increases and the overall resistance decreases when

Investigation 10
What is the effect of decreasing the resistance of right side of the circuit on: a) the flow rate through the battery; b) the pressure difference across the battery; c) brightness of the left bulb HYPOTHESIS: Decreasing the resistance of the right side of the circuit on the flow rate through the battery will increase the flow rate. Decreasing the resistance of the right side of the circuit on the pressure difference across the battery will have no influence. Decreasing the resistance of the right side of the circuit on brightness of the left bulb will decrease the brightness of the bulb.

SAMPLE DATA: Lighting || Compass Deflection || deflects || than A || than B ||
 * Circuit || Bulb
 * A || Bulbs are lit || Compass
 * B || left bulb decreases || more deflection
 * C || left bulb deceases || more deflection

CONCLUSION: My hypothesis was correct. When more bulbs were added with smaller resistance, the flow rate increased supported by the compass deflections. The pressure difference is not affected. The brightness of the bulb on the left side decreased when the resistance decreased on the right side.

Ammeter-Voltmeter Lab
Calculations

Practice Set 4
What determines Pressure in the Wires?