Weird question, but...what does it feel like to touch an infant incubator in use, like if you put your hand on the glass or something? Would it be warm to the touch? Would it vibrate/hum as a result of the machinery working? I've looked at the Wikipedia entry for "neonatal intensive care unit" and Googled "what does an infant incubator feel like", the latter of which is weirdly specific but I couldn't figure out how to get a more general search phrase, and anyway Google has some odd stuff in its search suggestions...
The reason I ask this is because I have a character who is touching something, and I wanted to compare the sensation to when he visited his premature infant daughter in the NICU and laid his hand on the incubator machine. It's meant to be a tiny detail of foreshadowing/in-joke, but it's not a big deal if I can't swing the comparison. (Guess which fandom I'm writing for. Go on, guess.)
Thanks in advance!
EDIT: Got the answers I was looking for, thanks to everyone who replied!