Wheelbarrow and autoclave: what they have in common

1. Step 1. Wheelbarrow — is a kind of — Cart. A wheelbarrow is a small one-wheeled cart pushed by a person.
2. Step 2. Cart — evolved into — Carriage. A covered cart on springs.
3. Step 3. Carriage — has part — Leaf spring. Leaf springs softened the ride of carriages.
4. Step 4. Leaf spring — is a kind of — Spring. A spring.
5. Step 5. Spring — is part of — Safety valve. A spring-loaded valve.
6. Step 6. Safety valve — is part of — Autoclave. A safety valve releases pressure.

Open Evothings