Batteries in series: brighter or burnt
One, two and three 4.5 V batteries power identical 6 V bulbs. One glows dim, two bright, three burns the bulb.
2D
Age 9+10 min
Electricity
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Press “Run”. Bodies move by the laws of physics: gravity, friction, elasticity.
What the experiment shows
Batteries in series add up their voltages. A bulb is made for one voltage: less makes it dim, more overheats it.
How to run it
- Press “Run” and compare the three bulbs.
- Hover over a bulb: you see voltage, current and power.
- Add a resistor to the third circuit so the bulb survives.
Questions to discuss
- Why do torch batteries go plus to minus?
- How much does power grow when the voltage doubles?
The science
Voltages of series sources add: U = U₁ + U₂ + … The bulb current is I = U/R and the power P = U²/R — doubling the voltage quadruples it.
Try it at home
Look how batteries sit in a remote or toy and what total voltage is written on the lid.
What to change in the editor
- Flip one battery in the second circuit.
- Use 12 V bulbs.