I always thought that when smoked it enters the blood stream almost instantly, then wares of over a few hours , where as eating is slowly moved through the digestive system over many hours giving much more time to absorb the thc . I once made some fairy cakes with a few friends and 2 hours in we were duck taping the light shades to the ceiling because the light was blinding us....... funny times , woke up the next day just as high as when i went to bed , very strange feeling : )