Question

You take a pickle jar from the refrigerator and try to open it up, but the lid will not turn. In order to make the jar easier to open, you hold the lid and jar under warm tap water for a few seconds. After this, the jar is much easier to open. Which of the following best explains why this trick works?

A) The lid and the jar rim both expand, so now the larger lid is easier to grip.

B) The lid and the jar rim both expand, but the lid expands more than the glass.

C) The metal lid expands under the warm water, but the glass jar rim contracts.

D) Magic.

E) None of these explanations is correct.

Answer 1

Running hot water over a tight metal lid on a glass jar makes it easier to open because both the lid and the jar rim expand, but the lid expands more than the glass.

Step-by-step explanation:

The best explanation for why running hot water over a tight metal lid on a glass jar makes it easier to open is option B) The lid and the jar rim both expand, but the lid expands more than the glass.

When the lid is held under warm tap water, the metal lid expands due to the increase in temperature. As a result, the lid becomes slightly larger and easier to grip. The glass jar rim also expands, but it expands less than the metal lid, which makes unscrewing the lid easier.

Therefore, warm tap water helps to loosen the lid by causing differential expansion between the metal lid and the glass jar rim.