Charcoal and tank: what they have in common
- Step 1. Charcoal — is material for — Gunpowder. Gunpowder is a mix of saltpetre, sulphur and charcoal.
- Step 2. Gunpowder — is used in — Cartridge. The charge.
- Step 3. Cartridge — is part of — Machine gun. Cartridges in a belt.
- Step 4. Machine gun — is part of — Tank. The Mark I’s machine guns.