Materials
Plastic comb or balloon
Wool sweater or cloth
Sink with faucet (narrow stream)
PVC pipe (30cm)
Silk cloth
Small pieces of paper
Humidity meter
Procedure
1. Turn on faucet to produce a thin, steady stream of water.
2. Rub the plastic comb vigorously against the wool cloth for 30 seconds.
3. Slowly bring the charged comb near the water stream (within 2cm, not touching).
4. Observe and measure the deflection of the water stream.
5. Repeat with a charged balloon and charged PVC pipe.
6. Test at different distances (1cm, 2cm, 5cm, 10cm).
7. Record ambient humidity for each trial.
Observations
Comb caused visible stream deflection of ~3cm at 1cm distance, ~1cm at 2cm, negligible at 5cm. Balloon produced larger effect: ~5cm deflection at 2cm distance. PVC pipe was strongest: ~7cm deflection at 2cm. At 10cm, only the PVC pipe produced any visible effect. Humidity was 45% on test day. A second session at 72% humidity produced noticeably weaker effects across all materials. Paper pieces were attracted and stuck to all charged objects.
Notes
Demonstrates electrostatic attraction on polar water molecules. The humidity sensitivity is an important variable — water vapor in the air dissipates charge faster. PVC + silk is a more effective triboelectric pair than plastic + wool. Simple but effective demonstration of charge and polarity.