There are six alkali metals: Lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and francium (Fr). You’re probably familiar with lithium, since it’s inside the batteries of all your electronic devices.
But did you know that you could cut a block of it with a simple knife and that it floats on water while it hisses hydrogen out? And that caesium just explodes when you throw it into water?
I didn’t, probably because I skipped that chemistry class. Or maybe I didn’t skip it but I forgot about that school year entirely. In any case, I’m a sucker for demonstration videos in which things explode while being explained by British narrators.