Activity 1:What will happen to bulbs 1 and 2 when you disconnect the wires at various points?
Series Circuit
Conclusion: If the circuit is not complete, the light bulbs will not light up because the current will not be able to flow through the circuit.
Worksheet 1:
1. In the following circuit, which bulb lights first?
Series Circuit
Answer: (D) They all light at the same time.
Series Circuit
Neither bulb lights up.
Series Circuit
Only Bulb A lights up.
Series Circuit
Both bulbs light up.
Activity 2: Make a light bulb light up using one cell, one bulb, and one wire.
The picture is not very clear but you can still see that the light bulb was lit. We used a battery and a wire to create a circuit in which the light bulb would be able to light up. The light bulb had to touch the battery in order to complete the circuit.
Worksheet 2: Your job is to trace the CCP and determine which of the bulbs will light.
Series Circuit
Both bulbs should be lit but we made a mistake as it is a closed circuit that should include both bulbs and not just one of them.
Series Circuit
Both bulbs are lit but it is not visible in the picture.
Series Circuit
One bulb is lit but it is not visible in the picture. Only Bulb 1 is lit because it is part of the closed circuit. The circuit does not include Bulb 2, which is why it is unlit.
Series Circuit
One bulb is lit while the other is unlit. Only Bulb 1 is lit because it is part of the closed circuit. The circuit does not include Bulb 2, which is why it is unlit.
Series Circuit
None of the light bulbs are lit because the circuit never connects.
Conclusion: In order for the light bulbs to be lit, the circuit has to be closed. More importantly, the current must travel through the tip point of the bulb so that it can complete the circuit.
Section 2: Schematic Diagrams and Charge Flow
Activity 1: How is air moving through a straw analogous to charge moving through a filament?
It takes much longer to exhale the air in your lungs through a coffee straw compared to a soda straw.
The speed of the air flowing through the coffee straw is slower than when it passes through the soda straw.
The soda straw needs less time for the air to pass through it.
The reason why the coffee straw takes longer is because it has more resistance. Since its cross-sectional area is smaller, its resistance is smaller since they are directly proportional. On the other hand, the soda straw takes less time since its cross-sectional area is much larger than that of the coffee straw, which means it has less resistance.
This relates to a charge moving through a current because if the circuit has more resistance, the current will move slower. If the circuit has less resistance, the current will travel faster.
Activity 2A (Series Circuits): How does the number of bulbs in a single loop affect the overall resistance of the circuit?
This light bulb is brighter because there is only one resistor in the circuit which allows more current to pass through.
The light bulbs are half as bright as they were in Circuit A.
The light bulbs were barely lit in this circuit.
Conclusion: The brightest light was produced by Circuit A and the least bright light was produced by Circuit C. This was because the more light bulbs in the circuit, the higher the resistance which means less current will pass through the circuit. Therefore, the more light bulbs connected in series, the greater the resistance of the circuit.
Activity 2B (Parallel Circuits):How does the number of bulbs in PARALLEL loops affect the overall resistance of the circuit?
This bulb is lit
The bulbs are just as bright as Circuit A.
These bulbs are the same brightness as the previous circuits.
Conclusion: The current in Circuit C is the highest, and the current in Circuit A is the lowest. but the brightness of the bulbs do not change. The more resistors connected in parallel, the less resistance and as a result there is more current. While the total current increases as a whole, the bulbs will not get any brighter because the same amount of current goes to each bulb.
Worksheet:
If you want to have maximum resistance in a circuit, put in a series circuit. If you want to have minimum resistance in a circuit, put it in a parallel circuit.
More charge flows through a single bulb circuit than through a two bulb circuit:
More charge flows through a single bulb circuit than through a two bulb circuitin a series circuit.
Charge flows at a greater rate through 1 bulb than two bulbs:
Charge flows at a greater rate through 1 bulb than two bulbs in a series circuit.
A single bulb shines brighter than either bulb in a two-bulb circuit:
A single bulb shines brighter than either bulb in a two-bulb circuit in a series circuit.
The total resistance of two bulbs is greater than a single bulb:
The total resistance of two bulbs is greater than a single bulb in a series circuit.
The difference between a wire and light bulb is that the wire has negligible resistivity while the light bulb has a high resistivity.