In a hot summer day the ice-cream
street vendor was making ice-cream, right in the street in a steel
pot without a freezer or use of electricity. How could he
produce such a cold environment to freeze milk and make ice-cream
under the hot sun using some crushed ice? Knowing how chemicals
can modify freezing point or boiling point of liquids, can help us
control the conditions or produce products that otherwise we
would not be able to do produce.
We also use such knowledge to
make anti-freeze and prevent freezing at very low temperatures or
use chemicals to melt ice.