Question

A plastic bottlefully filled with water cracks if it is kept in the deep freezer overnight.

Answer 1

Answer:

Explanation:

It probably will not crack when ‘kept’ in a deep refrigerator, but when it is subjected to a rapid change of temperature. This will create tensions inside the glass due to rapid and unequal thermal shrinking from point to point.

You may find it interesting, that lenses of telescopes are sometimes cooled for years, one degree or less per day, to avoid that they develop cracks.

You should perform the following experiment:

1. Put the bottle for a day in the refrigerator. (2 ⁰C)

2. If it doesn’t crack, put it for another day in a mild freeze. (-5 ⁰C)

3. Then put it in the deep freeze.

Anyway, glassware which is characterized as ‘microwave-safe’, is probably made out of low-coefficient-of-expansion glass and will without problem withstand the ‘thermal shock’, but bottles are usually not made out of such glass.