【英语时差8,16】雪会说话？（上）（在线收听）

“Probably all, or nearly all, who have experienced a cold winter, are familiar with the cheery cry of the snow as it is pressed against a hard surface by the steel tire of a wagon, for instance, or even onto a pavement by the heels of one’s boots.” Those words were written many decades ago by the physicist W.J. Humphreys in a book called Physics of the Air. Humphreys went on to suggest that creaking of snow is connected with very cold temperatures. Humphreys said that when the temperature is just below freezing and snow is easily packed into snowballs, footsteps and rolling wheels won’t create much sound. His reasoning is based on the fact that applying pressure to ice lowers its melting temperature. If ice is so warm that it’s about to melt anyway — say, at a temperature of 30 or 31 degrees Fahrenheit — then a little pressure will be all that is necessary to melt it.