Are those gas discharge tubes dangerous? I found atom spectra interesting, so I booked a 1.5 hour lab session at a local high school. The physics teacher gave me a few hydrogen tubes, helium tubes, nitrogen tubes and carbon dioxide tubes, a grating, a spectrometer and a 12 kv generator. Because I have university degrees in Biology, she just trusted me, left me alone and went back to take care her students.
At first I used the spectrometer, but later I found it's easier if I directly see through the grating. So, basically I stared at those tubes for a bit longer than 1 hour, in order to find those spectral lines. When I went back home, I searched for theoretical knowledge, and realised that I might have been exposed to UV radiations. But if so, should the school let the student see those tubes? So, I'm a bit confused. Are those tubes safe for the students and teachers? For me, I felt my eyes were quite sore, but I am OK after a night sleep.