Smell and taste
Chances are, you've witnessed a toddler stick a variety of objects, dirty or clean, edible or not edible, in their mouths. While the grown-ups might wrinkle their noses, the toddlers are using their senses of taste and smell to actively learn about the world--even the yucky parts!
Children learn about their world from actively exploring it. Smell and taste are related to mood, pleasure, and safety. As children explore smell and taste, they learn to regulate their moods, articulate their preferences, and take safety precautions. Even though it can get messy, try to encourage children's taste and smell exploration as much as possible. Intervene when they are in harm's way, but otherwise let them stick their noses in the bushes and try out lots of different foods.
Smell and taste can be a part of your playspace. For instance, include the natural, safe smells of herbs, flowers, and spices and let children try to identify them. (Be sure to separate these into one area so sensitive people can avoid these smells, too.) Smells will add variety and richness to your playspace. Flowers and plants will add fresh natural scents to your playspace. When food is a part of play, include time for slow tasting and smelling. Ask children what they like to smell and taste — and what they don't!