Physics
CircuitBuilding Lab
Safety Precautions: NONE of the experiments below involve the wall socket as a source of electricity. Do not put anything near the wall socket. If anything gets hot, disconnect the circuit so that current stops flowing and inform the teacher. If you feel a shock, leave the device alone and inform the teacher. Do not blow out light bulbs by hooking more than one battery to them.
In this lab we will build circuits. We will use batteries, light bulbs, and resistors.
Station 1:
Measure the voltage and current of a circuit built using the variable resistor and a battery. Try both 9V and 1.5V batteries and record the following:
Minimum resistance:
9V:
Voltage:
Current:
Resistance:
1.5V:
Voltage:
Current:
Resistance:
Maximum resistance:
9V:
Voltage:
Current:
Resistance:
1.5V:
Voltage:
Current:
Resistance:
Station 2:
Build a series circuit with two light bulbs. Apply potential and see what happens.
Draw a schematic of the circuit and answer the following questions on it:
Which bulb is brightest?
Which is dimmest?
Hook the battery to the circuit the opposite way.
Draw a schematic of the circuit and answer the following questions on it:
Which bulb is brightest?
Which is dimmest?
What happens when you remove a bulb?
Station 3:
Build a parallel circuit with two light bulbs.
Draw a schematic of the circuit and answer the following questions on it:
Which bulb is brightest?
Which is dimmest?
Hook the battery to the circuit the opposite way.
Draw a schematic of the circuit and answer the following questions on it. Attach this on a separate sheet.
Which bulb is brightest?
Which is dimmest?
What happens when you remove a bulb?
Station 4:
Use the circuit kit to build a circuit with a 100 ohm resistor in series with a motor.
What happens? Draw a circuit diagram for your circuit.
Now, build the same circuit with the resistor and motor in parallel. Draw a circuit diagram for your circuit. What happens? Explain why.
Station 5:
Use the circuit kit to build a circuit with the LED and the motor in series, then in parallel. Draw both circuit diagrams. For both circuits measure the voltage across the LED and the motor and record. In which circuit is the LED brighter? Explain why. For the series circuit add the two voltages. How does this compare the voltage of the batteries? What are the voltages in the parallel circuit?
Station 6:
Set up a circuit with the motor. Use the hand generator to turn the motor. Now, try with a 100 ohm resistor in series with the motor. Try it with the 100 ohm resistor in parallel with the motor. Now, replace the resistor in parallel with a metal connector. Which case is easiest to turn the crank? Explain.
Station 7
Hook the hand generator up to a parallel circuit with two bulbs and a series circuit with two bulbs. For which circuit is it harder to turn the crank? Explain why.
Take the parallel circuit and add a resistor to one of the paths. How does this affect the brightness of the bulb in that path compared to without the resistor?