Is the pool empty? No, an invisible gas that is heavier than air fills it. How could it be made visible?https://www.physik-astro.uni-bonn.de/en/news/prof-klaus-desch-macht-den-auftakt-zu-der-kinderuni-im-sommersemester-2024/uni-vl-kinderuniw-150424-076.jpg/viewhttps://www.physik-astro.uni-bonn.de/en/news/prof-klaus-desch-macht-den-auftakt-zu-der-kinderuni-im-sommersemester-2024/uni-vl-kinderuniw-150424-076.jpg/@@images/image-1200-c0c77bf7b8e7e1ed5bbb22dd13984902.jpeg
Is the pool empty? No, an invisible gas that is heavier than air fills it. How could it be made visible?
