User blog comment:TrustyPistol/Instant Creation/@comment-5260304-20130618164258

Technically, you wouldn't be pulling something 'out of thin air' in that sense, you would be converting molecules of one thing into molecules of another. If you understand chemistry, then you know that that in order to get there, the reaction needs to either lose energy (be cooled down), gain energy (be heated up), or use some other catalyst (something added that causes a rection but doesn't take part in the reaction itself). For example, say you wanted water. Well, in order to do that, you would need to cool down the air until it reaches the dew point, where it would turn into water. As for a glass to put the water in, the closest you could get is silica, which is found in sand. In order for glass to be created, the silica has to be melted then formed into a glass shape and cooled. By that reasoning, you could theoretically create a glass of water from 'thin air'. However, it isn't practical. The process would require a massive amount of energy and is highly unlikely that even experienced psions could do this. So for now, leave God to God and just go inside to get a glass of water.