Helium is the second element in the periodic table, atomic number two. It was first discovered when they measured the spectrum of the Sun. It was found as a line in the spectrum that did not appear to be on Earth.
Balloons like this are filled with this dwindling resource, if I remember correctly it’s from a place in America. I think there is a world shortage.
Helium is the second lightest element, but unlike Hydrogen which is the lightest, it doesn’t react with anything. So Helium stays on its own, it escapes out of our atmosphere. Hydrogen on the other hand reacts with many elements and this results in H2O, water, as two hydrogen atoms link with one oxygen.
Coventry University had a whole series of videos on YouTube that was about the elements if I remember. It was very interesting and they discussed all the elements in the periodic table. It was presented by a professor with mad grey curly hair….