What do a landing plane, a baking cake, a cooling tower and sweetened tea have in common? They all involve a transfer of momentum, heat or mass.

• 一架着陆的飞机、一个正在烘烤之中的糕点、一座冷却塔和一杯加糖的茶，它们都有什么共同点?它们全都包含有动量、热量和质量传递。