Electrolysis through direct current can separate oxygen from hydrogen from water

I'm not sure how you would capture the pure oxygen though unless you just breathed it as you made it and I'm not sure the consequences of doing that either. At one point I took positive and negative lead from my truck battery (in the 1980s) to see if I could readmit Oxygen and hydrogen through my carburetor in my truck to get better mileage. But, because I really noticed no difference venting Oxygen and hydrogen directly into my carburetor of my truck I eventually gave up the idea as I didn't see any real difference doing that at that time. So, I have used electrolysis both from 8th Grade on in Science class and also used Electrolysis on my truck for a while in Mt. Shasta. You can easily separate oxygen and hydrogen in water by putting a positive lead and a negative lead from your car or truck battery directly into a bowl of water or canister of water but it's better if the canister is plastic so it won't rust or conduct electricity. Also, you need to keep the two leads separate or that can be a problem too. Directly off of one lead will be oxygen and directly off of the other lead will be hydrogen. This is just how this works. When you put power to the two wires you will see bubbles coming up out of the water from the oxygen lead and the hydrogen lead. But, be careful of the hydrogen lead because remember the Hindenburg!

For example, you don't want to capture a whole lot of hydrogen under your hood in a pocket and then smoke a cigarette or you might blow the hood off your car or truck so be careful!

It's sort of like Teenagers or men lighting methane farts from their behinds with a lighter or match. YOU CAN get injured or maybe even die if you don't know what you are doing. At the very least you might ruin your pants or burn a hole in them. At worst usually you have to see a doctor because you burned your anus or rear end in some way.

Just remember that hydrogen and Oxygen together are much much more dangerous than Methane farts! So, if you don't know what you are doing it could be dangerous!

If you know which is which by lighting the hydrogen then you know the one that doesn't catch fire all by itself is the oxygen. However, just remember what an acetylene torch does with oxygen. It burns right through steel and likely even stainless steel. So, Oxygen is also dangerous around flammable things if it gets into proximity with them it makes them burn faster and hotter like it does with acetylene.

So, I could see Blacksmiths also using Oxygen when they want their fires to burn especially hot if they know what they are doing.