Lead–acid battery and LIGO: what they have in common

1. Step 1. Lead–acid battery — is part of — Submarine. Underwater, electric motors run on batteries.
2. Step 2. Submarine — has part — Periscope. A periscope.
3. Step 3. Periscope — has part — Mirror. Mirrors or prisms.
4. Step 4. Mirror — is part of — Laser. A resonator made of mirrors.
5. Step 5. Laser — is used in — LIGO. A laser.

Open Evothings