Harness and fuel cell: what they have in common
- Step 1. Harness — is part of — Parachute. Straps that hold a person.
- Step 2. Parachute — is made of — Silk. The canopy is silk.
- Step 3. Silk — is material for — Hot air balloon. The Montgolfier balloon was fabric lined with paper.
- Step 4. Hot air balloon — evolved into — Airship. A steerable balloon.
- Step 5. Airship — uses — Hydrogen. Zeppelins were filled with hydrogen.
- Step 6. Hydrogen — is used in — Fuel cell. The fuel is hydrogen.