Name: ________________________________________
Woodrow Wilson
Summer 2010
LIGHT BULB CIRCUITS
COMMON MISCONCEPTIONS OF LIGHT BULB ELECTRICAL CIRCUITS
A. When a circuit is closed, charge begins flowing from one end of the battery (which one?)
through the circuit until it gets to the other end of the battery. This belief will result in a
prediction that bulbs will light up in some progressive order when the switch is closed.
B. Charge gets “used up” as it flows through the circuit. This belief will result in a prediction
that bulbs in series will get progressively dimmer as charge flows from the battery through the
circuit.
C. The battery is a constant source of energy or current. This belief will result in a prediction
that adding or removing circuit elements will not change the total current or energy delivered by
the battery, which implies that single bulbs near the battery will never change their brightness.
D. The battery produces a fixed amount of brightness that is shared or divided among
bulbs, regardless of their number or arrangement. This belief may result in incorrect
predictions regarding the order of bulb brightness in combination light bulb circuits, and how the
brightness of bulbs change when one bulb goes out.
ACTIVITY 1: LIGHTING A BULB WITH TWO WIRES
Find two different ways to light the bulb
using only one dry cell and two wires.
Illustrate the two ways on the diagrams
below, showing the bulb and the two wires.
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Name: ________________________________________
Woodrow Wilson
Summer 2010
ACTIVITY 2: LIGHTING A BULB WITH A SINGLE WIRE
Find four different ways to light the
bulb using only one dry cell and a
single wire. Illustrate the four ways
on the diagrams below, showing the
bulb and the wire.
Use the circuit materials (D-cells, cell holders,
wire, Christmas tree lights, switch, etc…) to
construct and investigate the following circuits.
ACTIVITY 3: EFFECTS OF ADDITIONAL CELLS IN SERIES ON BULB BRIGHTNESS
1. Connect a single bulb in series with one dry cell
and a switch. Notice the brightness of the bulb.
2. Add a second cell in series with the initial cell and notice
the brightness of the bulb.
3. Continue adding up to six cells in series and describe
what happens to the brightness of the bulb as the battery
is comprised of more and more cells in series.
Draw a circuit diagram for a light bulb circuit
with a single bulb and four cells in series.
4. Use your knowledge of cells, voltage, current, and resistance from earlier investigations to explain your
observations.
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Name: ________________________________________
Woodrow Wilson
Summer 2010
ACTIVITY 4: EFFECTS OF ADDITIONAL CELLS IN PARALLEL ON BULB BRIGHTNESS
1. Connect a single bulb in series with one dry cell
and a switch. Notice the brightness of the bulb.
2. Add a second cell in parallel with the initial cell and
notice the brightness of the bulb.
3. Continue adding up to six cells in parallel and describe
what happens to the brightness of the bulb as the battery
is comprised of more and more cells in parallel.
Draw a circuit diagram for a light bulb circuit
with a single bulb and four cells in parallel.
4. Use your knowledge of cells, voltage, current, and resistance from earlier investigations to explain your
observations.
ACTIVITY 5: MULTIPLE BULBS IN SERIES
Draw a circuit diagram for a light bulb circuit with
four bulbs in series. Label the bulbs A, B, C, and D.
1. Connect a single bulb in series with three dry
cells and a switch. Notice the brightness of the bulb.
2. Add bulbs in series with the initial bulb and describe
what happens to the brightness of individual
bulbs as more and more are connected in series.
3. Compare the brightness of four bulbs in series with
each other.
4. Does the order of bulb placement affect their brightness? ______ What would you have students do to
find out the answer to this question?
5. When the switch is first closed, do all bulbs in series light at the same time, or one after the other?
6. What happens to the brightness of the other bulbs when one bulb goes out?
ACTIVITY 6: MULTIPLE BULBS IN PARALLEL
Draw a circuit diagram for a light bulb circuit with
four bulbs in parallel. Label the bulbs A, B, C, and D.
1. Connect a single bulb in series with three dry
cells and a switch. Notice the brightness of the bulb.
2. Add bulbs in parallel with the initial bulb and describe
what happens to the brightness of individual
bulbs as more and more are connected in parallel.
3. Compare the brightness of four bulbs in parallel with
each other.
4. Does the order of bulb placement affect their brightness? ______ What would you have students do to
find out the answer to this question?
5. When the switch is first closed, do all bulbs in parallel light at the same time, or one after the other?
6. What happens to the brightness of the other bulbs when one bulb goes out?
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Name: ________________________________________
Woodrow Wilson
Summer 2010
ACTIVITY 7: BULB BRIGHTNESS IN COMBINATION (i.e., not all series or parallel)
Draw a schematic diagram to the right of each circuit. Label the bulbs in these circuits A, B, C, D, etc…
Construct the circuits and list the order of bulb brightness from brightest to dimmest (Example: X > Y =
Z > W). Use up to six dry cells, if necessary, to best determine the brightness of each bulb.
A.
B.
C.
D.
E.
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Name: ________________________________________
Woodrow Wilson
Summer 2010
ACTIVITY 8: BULBS IN COMBINATION (i.e., not all series or parallel)
A. Construct this combination circuit containing a switch,
three bulbs, and three D-cells. Label these bulbs A,
B, and C. Rank the bulbs from brightest to dimmest.
(Example: X > Y = Z > W)
 What happens to the brightness of the other bulbs
(gets brighter, gets dimmer, goes out completely,
remains unchanged) if bulb A goes out?
Bulb B: _________________________ Bulb C: _________________________
 What happens to the brightness of the other bulbs (gets brighter, gets dimmer, goes out completely,
remains unchanged) if bulb B goes out?
Bulb A: _________________________ Bulb C: _________________________
 What happens to the brightness of the other bulbs (gets brighter, gets dimmer, goes out completely,
remains unchanged) if bulb C goes out?
Bulb A: _________________________ Bulb B: _________________________
B. Construct this combination circuit containing a switch,
three bulbs, and three D-cells. Label these bulbs A,
B, and C. Rank the bulbs from brightest to dimmest.
(Example: X > Y = Z > W)
 What happens to the brightness of the other bulbs
(gets brighter, gets dimmer, goes out completely,
remains unchanged) if bulb A goes out?
Bulb B: _________________________ Bulb C: _________________________
 What happens to the brightness of the other bulbs (gets brighter, gets dimmer, goes out completely,
remains unchanged) if bulb B goes out?
Bulb A: _________________________ Bulb C: _________________________
 What happens to the brightness of the other bulbs (gets brighter, gets dimmer, goes out completely,
remains unchanged) if bulb C goes out?
Bulb A: _________________________ Bulb B: _________________________
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