Electrostatics and Electrical Safety
This interactive simulation demonstrates key concepts about static electricity and electrical safety from Example 2.7.
1. Comb Run Through Dry Hair Attracts Paper
Key Concept: Static Electricity
When two different materials rub together (like comb and hair), electrons can transfer, creating static charge.
What's happening: Running a comb through dry hair transfers electrons, charging the comb. The charged comb polarizes paper molecules (positive side toward comb, negative side away), creating attraction.
Why wet hair is different: Water is conductive, so any charge immediately dissipates rather than building up.
2. Why Aircraft Have Conducting Tyres
Key Concept: Static Discharge
Large objects moving through air (like aircraft) build up significant static charge that needs safe discharge.
Why it matters: Aircraft can accumulate 100,000+ volts of static electricity during flight from friction with air particles.
Safety solution: Conducting tyres allow this charge to safely discharge to ground during landing, preventing dangerous sparks near fuel tanks.
3. Grounding Straps on Fuel Trucks
Key Concept: Grounding
Providing a controlled path to ground prevents dangerous static discharges.
The danger: Fuel trucks can build up static charge from fuel movement. A single spark could ignite vapors.
Safety solution: Metallic grounding straps (those hanging chains) provide a safe path for static electricity to discharge to ground before fueling.
4. Why Birds Don't Get Electrocuted on Power Lines
Key Concept: Circuit Completion
Electric current only flows when there's a complete circuit with a potential difference.
Bird safety: When a bird sits on one wire, there's no voltage difference across its body, so no current flows.
Human danger: A person touching the wire while grounded creates a voltage difference (wire to ground), allowing current to flow through their body.