Connecting Electric Bulbs in Series in Electricity Current and it’s Effects – Class 7 Science Experiment
Chapter Name: Electricity Current and it’s Effects
Activity Name: Connecting Electric Bulbs in Series in Electricity Current and it’s Effects
Activity Description:
In this experiment, you will connect three electric bulbs in series using dry cells. You will observe the brightness of each bulb when connected in different configurations. Additionally, you will disconnect one of the bulbs to observe the effect on the other bulbs in the series.
Required Items:
- Three torch bulbs
- Dry cells (at least three)
- Connecting wires
Step by Step Procedure:
- Connect the three torch bulbs in series using connecting wires. In series connection, the positive terminal of one bulb should be connected to the negative terminal of the next bulb and so on until all three bulbs are connected in a continuous loop.
- Connect this series circuit to a dry cell.
- Observe the brightness of each of the three bulbs when the circuit is complete with one dry cell.
- Add one more dry cell in series with the first cell (positive terminal to positive terminal, negative terminal to negative terminal).
- Again, observe the brightness of each bulb with the increased voltage from the two dry cells.
- Repeat step 4, adding one more dry cell in series with the first two cells, and observe the brightness of the bulbs.
Experiment Observations:
- When connected with one dry cell, the bulbs will have a certain brightness level.
- When an additional dry cell is connected in series, the bulbs will become brighter.
- When another dry cell is added in series, the bulbs will be even brighter.
Precautions:
- Make sure the connections are secure and the bulbs are properly inserted into the holders.
- Handle the dry cells carefully to avoid any short-circuits or accidents.
- Do not touch the bulbs when they are lit, as they can become hot.
Lesson Learnt from Experiment:
In a series connection of bulbs, the brightness of the bulbs increases when more cells are added in series. However, if one bulb gets fused or disconnected, it will break the loop, and all the other bulbs in the series will stop glowing. This phenomenon is commonly observed in serial bulbs used in decorative items during celebrations like marriages and festivals.
