Skate boot and gas lamp: what they have in common

1. Step 1. Skate boot — is part of — Ice skates. A boot.
2. Step 2. Ice skates — uses — Friction. Very low friction on ice.
3. Step 3. Friction — is used in — Match. It lights by friction.
4. Step 4. Match — uses — Combustion. Combustion.
5. Step 5. Combustion — is used in — Gas lamp. The flame gives the light.

Open Evothings