So I was just scouting for some cool mini science projects on youtube, and I accidentally found this :
As it says in the video, you should rapidly put this metal in a jar, or even better, in mineral oil. Being the first metal in its group, it’s( I think) the most reactive metal. It’s so reactive that it reacts just standing in the air ( you can see in the video that it gets black).
One can make awesome reactions with it or just burn it, it burns with a light comparable to that of sun. Have fun! ( if you have the money, these batteries are expensive =)) )