Getting ready for bed in the bathroom. DS8, is picking on his toothbrush, complaining about an "invisible bit of thread" sticking to it.
DD4, in great indignation: "But DS, that is INCREDIBLE! The only thing in the world that is truly invisible is air!"
DS8, in even greater indignation: "DD, there are LOADS of things that aren't air that are invisible!" And he starts listing colourless gases. DD4 runs out oft he bathroom while he is still muttering about the density of sulfur hexafluoride.

I have had exactly one year of chemistry in school and most of these days I have no idea what he is talking about.

Last edited by Tigerle; 01/07/15 07:03 AM.