Water Droplet Static Electricity Experiment
A challenging, hands-on discovery and STEM project designed for curious young minds aged 10 to 14.
Materials Needed
- • Clean metal food cans (soup or coffee cans) (2 units)
- • Bare copper wire (formed into two 5 cm rings) (1 meter)
- • Plastic jug with two adjustable dripping nozzles/valves (1 unit)
- • Insulated electrical hookup wire (with alligator clips) (2 leads)
- • Insulated plastic tray base and water (1 set)
Pro Tips
- → Lord Kelvin invented this machine in 1867: two streams of dripping water pass through copper rings into cans below.
- → Cross-connecting Ring A to Can B and Ring B to Can A creates positive feedback: slight random charge imbalances multiply exponentially.
- → Within 30 seconds of dripping, thousands of volts build up between the spark electrodes until tiny blue electrical sparks snap across the gap.
Safety First
Electrostatic sparks have high voltage but negligible current; completely harmless, but avoid near sensitive computer electronics.
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Step-by-Step Instructions
Step 1
Mount two clean metal cans on an insulating plastic sheet beneath two copper wire induction rings.
Step 2
Cross-wire the system using insulated hookup wire: connect Can A to Ring B, and Can B to Ring A.
Step 3
Position a water reservoir above so two steady streams break into individual drops right as they pass through the centers of the rings.
Step 4
Bring the discharge wire tips 2 mm apart: observe tiny electrostatic sparks crackle across the gap as thousands of volts build up.