Fuel cell and stone tool: what they have in common

1. Step 1. Fuel cell — uses — Hydrogen. The fuel is hydrogen.
2. Step 2. Hydrogen — is material for — Bubble chamber. The working medium is superheated liquid hydrogen.
3. Step 3. Bubble chamber — has part — Piston. It releases pressure.
4. Step 4. Piston — is part of — Syringe. A plunger.
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