The study tour has been disrupted by the snow in Pennsylvania. When it snows heavily, children get the day off. They are called 'snow days'. At first glance an idyll is conjured up; of happy children excited at a day off school throwing snowballs at each other.

Dig a little deeper and we find concerned teachers, worried about pupils being left at home in the cold without a proper meal. For many poverty-stricken pupils in the US, school also meets basic needs of warmth and nutrition.

And what about the effect of the snow on children's education? Most States have a number of school days that children must attend per annum. So at the end of the year, days lost to snow are taken out of vacation time. So holidays that should have started on say June 1st may not actually take place until half way through the month.