After filling a flask with boiling water and stoppering it the boiling stops, then, i ran cool water over the

Question

flask and the boiiling begins again why is this??

Answer 1

Because the boiled water is at a more higher temperature.(But if u use frozen an boiled water,u see the result is nothing meaning neither cold nor hot.

Answer 2

I'm not -entirely- sure, but my guess would be this.

When you stopper the flask, you're sealing the contents and fixing the volume; the pressure inside is no longer dependent upon the atmospheric pressure. Cold water on the outside of the flask will cool the glass and cool the air inside at a quicker rate than the water. Since colder air results in reduced pressure (remember, they're dependent upon one another), and boiling is a phenomenon that occurs with temperature AND pressure as variables, reduction of the pressure reduces the temperature required for boiling. So yes, the water is still boiling - just at a lower temperature due to the reduced pressure.