Let your children explore and make discoveries about their senses. Here's a popular activity and several variations for exploring the sense of touch with children from ages 3 to 7. Place several familiar objects in a sack. Have each child reach in, and using only the sense of touch, name the object before pulling it out. Have each child describe the object before pulling it out of the sack.
Children are likely to name the object first.
However, it is their ability to describe their observations that is important in developing critical thinking skills. Pull it out. Now pull out something hard. Now, find something that is the opposite of smooth. Have each child pull out two objects that are the same in some way, including use.