Studies have shown that even adults learn better when their sense of touch is involved in an activity. Toddlers, especially, rely on their sense of touch to explore the world. Make sure your toddler's play environment is filled with textures for him to explore. Science activities for toddlers should be sensory-rich and encourage the child to touch, smell, listen and observe. Trace shapes, letters and numbers on sandpaper or in a tray of salt or shaving cream. Make learning hands-on whenever possible.