Space helmet with visor and stone tool: what they have in common

1. Step 1. Space helmet with visor — is part of — Spacesuit. A transparent helmet with a light filter.
2. Step 2. Spacesuit — evolved from — Diving suit. A sealed suit with an air supply.
3. Step 3. Diving suit — has part — Piston pump. Air was pumped from the surface.
4. Step 4. Piston pump — works like — Syringe. A syringe is a hand-operated piston pump.
5. Step 5. Syringe — has part — Needle. A hollow needle.
6. Step 6. Needle — evolved from — Stone tool. Bone needles with an eye are part of the Palaeolithic toolkit.

Open Evothings