Whistling kettle and boyle’s air pump: what they have in common

1. Step 1. Whistling kettle — has part — Whistle. A whistle.
2. Step 2. Whistle — is made of — Bone. Ancient whistles were carved from bone.
3. Step 3. Bone — is material for — Needle. The first needles with an eye were carved from bone.
4. Step 4. Needle — is part of — Syringe. A hollow needle.
5. Step 5. Syringe — has part — Piston. A plunger.
6. Step 6. Piston — is part of — Boyle’s air pump. A plunger.

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