SERIES CIRCUITS LAB, PART 2
In this Investigation, you will:
- Build and compare series and parallel circuits.
- Apply your knowledge of circuits to a real situation.
There are two different types of circuits, called series and parallel circuits. Series circuits have only one path for the flow of current. Parallel circuits have two or more paths for the flow of current. What does a simple circuit that rings a warning bell in your car have in common with the complex circuits that run computers? All circuits use series and parallel circuits, by themselves or combined with each other. In this Investigation, you will build these circuits and explore a common application of them.
Safety Tips: Be careful working with batteries. If they are damaged, return them immediately to your teacher.
If a battery or wire gets hot, disconnect the circuit and ask your teacher for help.
Always have a bulb somewhere in your circuit. Do not connect a wire directly from one terminal of the battery to the other terminal or you will make a short circuit.
Part 1: Building two kinds of circuits
- Gather the following materials: two batteries and battery holders, two bulbs and bulb holders, and six connectors.
- Build Circuit 1 pictured at right.
- Trace the circuit path with a pencil from positive terminal to negative terminal. Does the current have any choice about where to go?
- Record the brightness of the two bulbs.
- Build Circuit 2 pictured at right. The circuit “branches” at the square dots. If you are not sure how to build this configuration, ask your teacher for help.
- Trace the circuit path with a pencil from positive terminal to negative terminal. Does the current have any choice about where to go?
- Record the brightness of the two bulbs.
Part 2: Applying series circuits and parallel circuits
If two switches are arranged in series, then both switches must be on for the circuit to work. This type of arrangement is called an AND circuit. If two switches are arranged in parallel, then only one switch needs to be on for the circuit to work. This type of arrangement is called an OR circuit.
Building an AND circuit
- Gather the following additional materials: two switches and one connector. Build Circuit 3 pictured to the right.
- Place a label next to each switch. Label one of the switches 1 and the other switch 2.
- Try all combinations of switches: both on, both off, #1 on and #2 off, and #2 on and #1 off.
- Record what happens to the bulb in each case.
Building an OR circuit
- Build Circuit 4 pictured to the right.
- Place a label next to each switch. Label one of the switches 1 and the other switch 2.
- Try all combinations of switches: both on, both off, #1 on and #2 off, and #2 on and #1 off.
- Record what happens to the bulb in each case.
Analysis: Complete in your notebook, then upload the photo to the assignment on Edmodo. (Make sure it is legible!)
- In Part 1, Circuit 1, does the current have any choice about where to go? Explain.
- In Part 1, Circuit 1, describe the brightness of the two bulbs.
- In Part 1, Circuit 2, does the current have any choice about where to go? Explain.
- In Part 1, Circuit 2, compare the brightness of the two bulbs with the brightness of the bulbs in Circuit 2.
- What is the difference between a parallel circuit and a series circuit?
- Which circuit from Part 1 is a parallel circuit? Which is a series circuit?
- In Part 2, Circuit 3, describe what happens to the bulb when: a) both switches are closed, b) when one switch is closed and one switch is open, and c) when both switches are open.
- In Part 2, Circuit 4, describe what happens to the bulb when: a) both switches are closed, b) when one switch is closed and one switch is open, and c) when both switches are open.
- How could you use Circuit 4 to light one of the rooms in your Electric House?