Similarly, it's fun to realize that the entire 27-km Large Hadron Collider "runs" on a small bottle of hydrogen that you could hold in your hand.

http://void.printf.net/~conor/sa/LHCb/LHCfuel.jpg

Without that insignificant-looking bottle the whole machine would have nothing to do.

(Edit: I do have to wonder how wise it is to paint a bottle of hydrogen to look like a fire extinguisher.)

Gas bottle colour codes and fire extinguisher colour codes are two distinct namespaces... Here's a handy chart: http://www.ior.org.uk/ior_/images/pdf/se/New%20Colour%20ID%2...

Wow, human factors=massive fail with that chart. "Hmm, is this acetylene or nitrogen?"

That's not even getting into the whole red-green color blindness issue that could lead to confusing 'Flammable' with 'Inert' contents.

You can't confuse acetylene or nitrogen, old or new style; acetylene uses maroon for the whole bottle, nitrogen uses black for the shoulder only. Also the cylinders are quite different shapes.

Also the colours are for "the room is on fire, quick what's in that gas bottle over there?" situations. Are you allowed to be a safety responder if you're colour blind? For everyone else the rule is pretty simple; GTFO, and if acetylene is involved, GTFO out of the postcode.

Still, you don't go out of your way to pick confusing colors. This is Usability 101 stuff.

If the room's on fire and I'm in it, I'm a 'safety responder' whether I want to be or not.

Video games have taught us that fire extinguishers blow up so it cancels out.