Adze blade and vacuum pump: what they have in common

1. Step 1. Adze blade — is part of — Adze. A blade across the handle takes shavings off a log.
2. Step 2. Adze — evolved from — Stone tool. Neolithic adzes were stone.
3. Step 3. Stone tool — evolved into — Needle. Bone needles with an eye are part of the Palaeolithic toolkit.
4. Step 4. Needle — is part of — Syringe. A hollow needle.
5. Step 5. Syringe — works like — Piston pump. A syringe is a hand-operated piston pump.
6. Step 6. Piston pump — evolved into — Vacuum pump. Guericke adapted the piston pump to pump out air.

Open Evothings