Why does a container of water, that has just been heated up and sealed off, boil when cold water is poured on?

Question

it also keeps boiling with the touch of a hand, does it have to do with the pressure?

Answer 1

It must be a rigid container (like glass) with air space above the water. When you heat it up, the water vapor (steam) pushes all of the air out; then, after you seal the container, if you cool the steam with cold water it condenses back to water, leaving a vacuum inside the container. The decrease in pressure lowers the boiling point of the water in the container, so that it boils. Then, when you heat it with your hand, you are adding more heat, which will also make it boil at the lower pressure.

Answer 2

When you pour cold water, you are condensing steam inside the container which pulls a vacuum inside the container, or at least lowering the pressure, so the water boils at a lower temperature from the heat held in the water.
When you put your hand on the side, you are raising the temperature locally just enough to trigger boiling in that area.

Answer 3

Y. The cold wter caues the steam in the jar to ondense, which leaves behind a parial vcuum, which causes the water o boil.again.