Can you use CO2 cartridges in a N2O dispenser? UNlike this post (Are N2O and CO2 chargers interchangeable for culinary purposes?) I want to know whether you can use the same dispenser for both carbon dioxide and nitrous oxide.
I see that the heads look aesthetically similar but is there any technical difference between downward- and upward-facing spouts?
i.e. what would happen if I put water in a cream dispenser and used a CO2 cartridge instead of cream and a N2O cartridge?
In general, yes, but check the manufacturers instructions...if you put water (or any liquid) in a whip cream dispenser, and use a CO2 cartridge,  you can carbonate the liquid...though there is some technique to employ if you want a well-carbonated liquid.