Blowing into the film is similar to blowing into a balloon: the rush of air makes the film stretch and expand. Surface tension makes the soap water molecules still attached to the wand automatically come together, closing the developing bubble's open end.往薄膜里面吹气就像往气球里面吹气:气流涌进使得薄膜伸展和扩张.表面张力使得附着在"魔术棒"上面的肥皂水分子自动地聚集在一起,合上不断变大的气泡的开口. _______________________________.