More Light Bulb Circuits
Objectives:
- Construct combination light bulb circuits based on descriptive explanations
- Compare brightness of bulbs within and across circuits
- Observe changes in bulb brightness within a circuit as specified individual bulbs “go out”
Materials:
- Christmas tree lights
- D cells
- D cell holders
- Electrical wire/clips
- Switch
Part I Procedure:
- Draw and label circuit diagrams containing arrangements of bulbs matching eachof the following circuit arrangement descriptions.
- Examine changes in the brightness of the remaining bulbs afterspecifiedbulbs“go out.”
- Give descriptions and explanations of your observations according to the outlined structure.
- “Bulbs B and C are in parallel with each other while in series with Bulb A”
Starting bulb brightness order = ______, because…
When Bulb B goes out, the total resistance
of this circuit ______, making the
total current in this circuit ______.
This leaves the remaining circuit equivalent to
the one drawn in the box to the right.
Bulb A gets ______because…
Bulb C gets ______because…
The new bulb brightness order = ______because…
What happens to the original circuit when Bulb A goes out?
- “Bulbs B and C are in series with each other while in parallel with Bulb A”
Starting bulb brightness order = ______, because…
When Bulb B goes out, the total resistance
of this circuit ______, making the
total current in this circuit ______.
This leaves the remaining circuit equivalent to
the one drawn in the box to the right.
Bulb A gets ______because…
Bulb C gets ______because…
The new bulb brightness order = ______because…
When Bulb A goes out, the total resistance
of this circuit ______, making the
total current in this circuit ______.
This leaves the remaining circuit equivalent to
the one drawn in the box to the right.
Bulb B gets ______because…
Bulb C gets ______because…
The new bulb brightness order = ______because…
- “Bulbs A and B are in parallel with each other while in series with Bulbs C and D, which are in parallel with each other”
Starting bulb brightness order = ______, because…
When Bulb A goes out, the total resistance
of this circuit ______, making the
total current in this circuit ______.
This leaves the remaining circuit equivalent to
the one drawn in the box to the right.
Bulb B gets ______because…
Bulb C gets ______because…
Bulb D gets ______because…
The new bulb brightness order = ______because…
IV. “Bulb A is in series with a parallel section that contains Bulbs B and C in series in one
branch and the single Bulb D in the other branch”
Starting bulb brightness order = ______, because…
When Bulb B goes out, the total resistance
of this circuit ______, making the
total current in this circuit ______.
This leaves the remaining circuit equivalent to
the one drawn in the box to the right.
Bulb A gets ______because…
Bulb C gets ______because…
Bulb D gets ______because…
The new bulb brightness order = ______because…
When Bulb D goes out, the total resistance
of this circuit ______, making the
total current in this circuit ______.
This leaves the remaining circuit equivalent to
the one drawn in the box to the right.
Bulb A gets ______because…
Bulb B gets ______because…
Bulb C gets ______because…
The new bulb brightness order = ______because…
What happens to the other bulbs when Bulb A goes out?
V. Construct your own circuit containing 5 bulbs. Make statements describing the changes in
bulb brightness when specific bulbs go out. Show all work in the space below.
Part II Procedure:
Given these descriptions of Circuits 1, 2, 3, and 4:
- “B and C are in parallel with each other while in series with A”
- “D and E are in series with each other”
- “F and G are in series with each other while in parallel with H”
- “I and J are in parallel with each other”
- Draw and label circuit diagrams containing arrangements of identical bulbs matching each of the four circuit arrangement descriptions.
Circuit 1.Circuit 2.Circuit 3.Circuit 4.
- Construct all four circuits. Use 2 dry cells for each circuit.
- Compare the brightness of all ten bulbs across all four circuits.
- Provide an explanation for your brightness order observations.Hint: You may find it easier to put in values for the battery’s EMF, make up values for the resistance of each bulb, and then use calculations.
1