First in school I learnt that when supplied enough energy, the electron in a hydrogen atom will jump energy level(s), denoted by $n=1$, $n=2$ and so on for integral values of $n$. Then I learnt about shells, subshells and orbitals and what they have to do with the quantum numbers $n$, $l$ and $m_...

We have an issue with our wash bottles. In our electronic lab, our students use isopropanol and acetone to wash manufactured parts. Unfortunately we noticed a strong evaporation over time. After about one month the wash bottles are empty. Is there any better kind of container for such use? Or is ...