Refraction of light and sewage treatment plant: what they have in common

1. Step 1. Refraction of light — is used in — Lens. A lens focuses light by refraction.
2. Step 2. Lens — is part of — Planetarium. Projectors.
3. Step 3. Planetarium — is made of — Concrete. Zeiss’s first dome was thin concrete.
4. Step 4. Concrete — is material for — Sewage treatment plant. The tanks are concrete.

Open Evothings