Bow drill and turbine: what they have in common

1. Step 1. Bow drill — evolved into — Electric drill. The oldest rotary drilling tool.
2. Step 2. Electric drill — works like — Dental drill. The same task — spinning a drill bit; the foot-powered dental drill appeared before the electric drill.
3. Step 3. Dental drill — has part — Turbine. An air-driven turbine handpiece.

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