Notes from Janice’s Desk
You smell things, such as a French Fries, because molecules leave the food and enter the air. When this air containing molecules from the French Fries enters your nose, special cells on the surface inside your nose capture the molecules. These special smelling cells have hairlike bristles covered with a slippery substance called mucus. First the food molecules dissolve in the mucus, then the bristles send a coded message to your brain which decodes the message and identifies the smell.
A keen sense of smell allows animals to locate food as well as avoid becoming food for predators. They also use their sense of smell to identify their off spring. 
A polar bear will lift its nose skyward to catch any scents drifting its way in the wind. These bears can smell food many miles away.
A dog can smell things that you cannot because it has about five times the amount of moist surface inside its nose. You can use strips of paper to make models to compare the difference in the inside surface area of a human’s nose to that of a dog’s nose. For instruction for preparing these models, see Sniffers.