A traditional Montessori olfactory exercise in the Sensorial area is the Smelling Bottle exercise in which there are several sets of matching scent bottles. The bottles look identical, so the child receives no visual clues, but matches the scents by scent.
A good starting array of smells includes cinnamon, black pepper corns, and vanilla. You can put them into sets of identical bottles or inside folds of fabric for mixing and matching. Since there are two of each, mark one of the pair in a different color -- you can mark the lids of the bottles or use different colored fabric for one.
You can introduce the names in a separate exercise after your child has worked with matching them. One good way to introduce the names to a group is to have everyone sit on the circle, you introduce the name of one scent, and then pass it around for everyone to sniff.
A fun expansion of the scent exercises is to have children close their eyes or wear a blindfold so they focus on only the scents!
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