I've done a little bit of research for this. Time to share to wealth!

So THCA is an acid due to a carboxyl (-COOH) group stuck on the molecule that is found naturally in cannabis. THCA actually has no psychological effects on the mind. THC is the active compound in pot that actually causes the psychological effects and is what you want in your body. So we want to be rid of the Carboxyl group by decarboxylating the molecule (taking off the -COOH). This turns THCA into THC (woot!) There is very little natural THC in weed unless it is a special strain which is why we don't just eat weed, we smoke it. When pot is burned, we are effectively reaching the temperature at which the carboxyl group leaves but its inefficient because it causes much THC to boil away around the flame.

Here are some interesting temperature stats:

Decarboxylation: 105 C (220 F)
Boiling of Cannabinoids: 127-200 C (260-392 F)
Boiling of THC: 200 C (392 F)
Flame on lighter: 1300-1977 F

So basically the temperature range you want is 220-260 F (I recommend 230 F for around 20 mins in the oven). This converts most THCA into THC which any way it gets into your body will have psychological effects. This decarboxylation is usually used for cooking because it activates the pot (instead of eating pot straight without activation). Eating is also much more efficient than smoking although it appears that many people have had increased yields when smoking as well. Happy smoking imp: