How to See the Wind

如何看见风的模样

On a dry, windy day, take a long polished sheet of metal( a saw-blade will do) with a perfectly¹ straight edge. Then sight carefully at some clearly defined object as shown, and you will see the air flowing over the saw's edge.

选一个晴朗，多风的日子，拿上一根较长，表面光亮，末端棱角分明的金属物（比如锯子的锯片）。瞄准远处某一清楚可见的目标物，你会看到空气在锯片的边缘上流动。