Our brain needs stimulation from all of our senses, from our eyes, ears, skin, tongue and nose. So, by touching something, it will give information to the brain and the brain will receive that information and keep it in the data base. The more we stimulate our brain through our senses, the more information we get! So basically, we can learn from everything around us.
My little Claire likes to find any kind of animals around the garden and she will ask me whether it’s ok or not to touch the animal. Sometime she finds a snail and so happy to see it. She touched the snail with her little finger and I can explain about the snail. How does it move, what color is the snail, what is the hard thing on the top of its body, etc. So, she can remember how does she feel when she touched it.