In the teahouse of Hupaoquan in Hangzhou, a group of tourists watched the waiter's performance with strange eyes. On the table, a bowl of water filled with a tiger running spring, the waiter gently sa

In the teahouse of Hupaoquan in Hangzhou, a group of tourists watched the waiter's performance with strange eyes. On the table, a bowl of water filled with a tiger running spring, the waiter gently said (1) The molecular distribution on the surface of liquid is less than that inside, and the attraction and repulsion between molecules are weakened, especially the repulsion, so there is mutual attraction between molecules on the surface, which is called surface tension, and even it can form an elastic film on the surface of liquid to hold the sewing needle without sinking.

(2) Guess: Surface tension always makes the liquid level shrink as much as possible.

Experimental design: make a round frame with thin iron wire and tie a loose cotton thread in the middle. Soak the wire frame in soapy water and take it out, and a tight soap film will be formed on the frame. If the left membrane of cotton thread is punctured with a needle, the right membrane will shrink under the action of surface tension, and the cotton thread will bend into an arc to the right until it is tight. If the membrane on the right is punctured, the cotton thread will bend into an arc to the left, which proves that the conjecture is correct.

So the answer is: (1) repulsion; Attraction; (2) atrophy.