In order to predict whether or not a single replacement reaction takes place you need to consult a chart that shows the

Activity series of metals. it is a series of metals based on their reactivity from highest to lowest. Potassium occupies the top most level of reactivity. The reactivity means the ability to displace hydrogen gas from water and acid solutions.

Elias is almost correct. he just got it backwards.the correct answer is that it demonstrates elastic potential energy transforming into kinetic energy.