Rubber eraser block and electronic calculator: what they have in common

1. Step 1. Rubber eraser block — is part of — Eraser. Rubber or PVC with an abrasive.
2. Step 2. Eraser — is used in — Pencil. Erasing.
3. Step 3. Pencil — is made of — Graphite. The lead is graphite mixed with clay.
4. Step 4. Graphite — is material for — Ion thruster. The grids are graphite or molybdenum.
5. Step 5. Ion thruster — has part — Solar panel. Power supply.
6. Step 6. Solar panel — is part of — Electronic calculator. Many run on a solar cell.

Open Evothings