Old Faithful is a geyser in Yellowstone that erupts every 44 to 125 minutes (according to Wikipedia). People are often told that the geyser erupts every hour, but in fact the waiting time between eruptions is more variable. Let's take a look.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.