Opening A Stuck Jar Lid
Classical Mechanics
Level
1
A common solution to open a stuck jar lid is to hold it under warm, running water. Why does this method work?
The metal lid expands more than the glass jar.
The glass jar contracts more than the metal lid.
Water flows into the gap between the lid and the jar, and decreases the friction between them.
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1 solution
Glass is virtually unaffected by thermal energy in terms of its shape. Any change at all only results when sufficiently heated to melting point. Metal however expands and contracts readily in accordance to its temperature due to a lattice structure of its atoms that exert surrounding force when vibrating with excess energy, thus requiring more space. You're welcome 😀