A blood blister forms when skin and small blood vessels are damaged without breaking the skin. Trapped beneath the skin surface is some blood and skin fluid. Blood blisters are commonly caused by accidents in which the skin is pinched by a tool or a heavy weight, or they may occur from constant rubbing back and forth.
1 Sunshine hours in Chicago, Illinois range between 3:42 per day in December & 10:14 for each day in July. 2  The longest day of the year is 15:02 long and the shortest day is 8:57 long.  The longest day is 6:04 longer than the shortest day.
Winter Solstice on December 21st: the longest night of the year. The shortest day of the year, the longest night occurs today, Sunday, December 21st. The so-called Winter solstice is an astronomical phenomenon that occurs in the North Hemisphere when the Earth North axis is at the longest distance to the sun.