Ladder rungs and smartphone: what they have in common

1. Step 1. Ladder rungs — is part of — Ladder. Rungs for the feet.
2. Step 2. Ladder — uses — Friction. The feet hold on the floor by friction.
3. Step 3. Friction — is used in — Air brake. Brake shoes slow the wheels through friction.
4. Step 4. Air brake — evolved into — Anti-lock braking system (ABS). Anti-skid systems first appeared in aviation and on railways.
5. Step 5. Anti-lock braking system (ABS) — has part — Hall sensor. Sensors measure the wheel speed.
6. Step 6. Hall sensor — is part of — Smartphone. A magnetometer compass.

Open Evothings