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.
There are two solstices, summer and winter, and two equinoxes, spring and fall, each year. The longest day of the year is the summer solstice, on the 21st or 22nd of June in the Northern Hemisphere. In this case, day means the time between sunrise and sunset. The winter solstice is the shortest day of the year. At each equinox, day and night are of equal length.