Following is an excerpt from Alexandra Horowitz's Inside of a Dog: What Dogs See, Smell, and Know. (If you want to learn more about how dogs experience the world, I highly recommend reading this book.)
“The sniff begins with muscles in the nostrils straining to draw a current of air into them–this allows a large amount of any air-based odorant to enter the nose. At the same time, the air already in the nose has to be displaced. Again, the nostrils quiver slightly to push the present air deeper into the nose, or off through slits in the side of the nose and backward, out the nose and out of the way. In this way, inhaled odors don't need to jostle with the air already in the nose for access to the lining of the nose. Here's why this is particularly special: the photography also reveals that the slight wind generated by the exhale in fact helps to pull more of the new scent in, by creating a current of air over it.”
This is far more advanced than the primitive sniffing of which we humans are capable. And it helps us to understand why their sense of smell is so much stronger than ours. It's fascinating stuff, to be sure! You might not think so, but I am a firm believer that the more we learn and understand about dogs and how they perceive the world, the better we will be at communicating with and understanding them. For those of us who train dogs, I think it helps us to become better trainers.
One thing that my clients hear me say over and over is that such a major part of training your dog effectively is learning to communicate clearly with your dog. The better we understand them, the more clearly we can communicate with them.
The idea of being able to communicate with an entirely different species (in this case, dogs) is fascinating to me. It takes a real effort on both species to understand and find common ground with each other. And making the effort to understand them is far more respectful than just expecting them to fit into our world without our trying to understand their world. I teach my dogs lots of things, but I think they always teach me more than I am able to teach them.