Scythe and heat pump: what they have in common

1. Step 1. Scythe — evolved from — Sickle. Mowing while standing, with a long snath.
2. Step 2. Sickle — evolved into — Combine harvester. The machine replaced reaping by hand.
3. Step 3. Combine harvester — has part — Belt drive. Belt drives.
4. Step 4. Belt drive — is part of — Supercharger. Belt-driven from the crankshaft.
5. Step 5. Supercharger — is a kind of — Compressor. A supercharger.
6. Step 6. Compressor — is part of — Heat pump. A compressor.

Open Evothings