Answer:
Placing cells in series increases the
voltage in the circuit by 1.5 V for each
cell. Increasing the voltage increases the
brightness of the bulb
Explanation:
I. MAKING THE CONNECTION
How many terminals are located on the battery? 2
How many terminals are located on the bulb? 2
II. PLACING CELLS IN SERIES
What is the effect on the brightness of the bulb by increasing the number of cells?
The bulbs become brighter when increasing the number of cells.
What changes occur in the current in the circuit when increasing the number of cells?
Increasing the number of cells increases the current in the circuit.
What changes occur in the voltage in the circuit when increasing the number of cells?
Increasing the number of cells increases the voltage (for cells in series the voltage is additive).
What changes occur in the resistance in the circuit when increasing the number of cells?
The resistance is determined by the number of bulbs. The resistance in the circuit remains unchanged.
III. PLACING BULBS IN SERIES
What is the effect on the brightness of the bulbs by increasing the number of bulbs?
Increasing the number of bulbs decreases the brightness of the bulbs.
What changes occur in the resistance in the circuit as more bulbs are added?
The resistance increases. In a series circuit, adding bulbs increases the resistance in the circuit.
What changes occur in the current in the circuit as more bulbs are added?
Increasing the resistance decreases the current.
Observations on unscrewing one bulb. Explain your observations.
A complete circuit requires the electrons to move from the negative terminal of the battery to the
positive terminal. When one bulb is unscrewed it opens the circuit preventing a complete circuit and
the electrons cannot return to the battery.
IV. PLACING BULBS IN PARALLEL
Compare the brightness with two bulbs in parallel with two bulbs in series.
Two bulbs in parallel are brighter than two bulbs in series.
How does increasing the number of circuits (bulbs) change the current and resistance?
In a parallel circuit each bulb is in its own circuit. As bulbs are added the resistance in the circuit
decreases since each circuit is another pathway for electrons to move from one end of the circuit
