But the outgo of this activity should do more than merely reduce pressure, as the escape of steam from a safety valve. It is a law of life that we both understand and retain most thoroughly the thing we do. This abounding activity is God's great provision for enabling the child to make his own that which he is receiving through his senses. It is handling and eating the apple that makes him understand what it is. It is playing that he is the father or the Sunday-school teacher, performing the act of helpfulness and love that enables him to enter into the meaning of these relations and duties of life. The problem of the Sunday-school teacher then is not "How can I keep the child still," but "How can I make this activity teach the child;" for, re-emphasizing the thought, "The child understands and remembers the action far better than the admonition." (2) _Imitation._ The activity of this period is distinctly imitative. Just as the child must learn to form letters by copying them before he can develop an individual style of writing, so he must learn right action by imitating it before he can be independent and original. Every time a child imitates an action he understands its meaning better, he fixes it more securely in memory and he also makes its repetition so much the easier. It is important, therefore, to note what he naturally imitates. In this period it is some definite act, not the spirit nor life of the actor. He does not aspire to resemble the character of the teacher, but he does try to speak and move and look as she does. As the action is performed, the life unconsciously but surely becomes like the one who is imitated. (3) _Curiosity._ Because the child has everything to learn God has made him want to learn everything. As physical hunger arouses an effort to supply the need for physical food, so mental hunger or curiosity arouses an effort to supply mental food. It is most active in the period of greatest absorption, when the life must store for future use. There are two points in relation to curiosity which it is important for the Sunday-school teacher to remember. (a) Its field of operation, or that toward which it is directed. Curiosity is selective, going out only toward those things in which the life is interested. In this period the child's interests are in activities in Nature and everyday life and in the things about him; but he desires to know only the simplest facts concerning them. What the object is, where it came from, and what it will do, usually satisfy his curiosity regarding it. The teacher, therefore, is guided in the selection of what shall be given the child in a lesson.