Who can teach me a little magic trick, any magic trick. Tell me everything you know?

Tomato sauce can sink and float. First drink the water in the mineral water bottle, make a small hole at the bottom, then fill it with tap water and put in the tomato sauce. Insert the one I drew myself and plug the holes with my hands to make the tomato sauce sink (or it may float, I can't remember...), and loosening it will do the opposite. ? Use mine, I have spent a lot of time on it, and answered it for the first time...