Coin and railway track: what they have in common
- Step 1. Coin — is made of — Silver. Silver coins.
- Step 2. Silver — uses — Electrical conduction. The best conductor.
- Step 3. Electrical conduction — is used in — Copper wire. Copper conducts current well.
- Step 4. Copper wire — is part of — Electrical telegraph. Communication lines.
- Step 5. Electrical telegraph — is used in — Time zones. Synchronizing time by telegraph.
- Step 6. Time zones — was inspired by — Railway track. Introduced because of railway timetables.