The FireTtriangle. Most people have heard of the fire triangle: heat, fuel, and oxidizer. When these three components come together in the proper proportions, a fireâthe rapid chemical reaction of fuel with oxygen, resulting in the release of heat and light energyâis bound to occur.
Answer by Hank W. The average length of the northern hemisphere summer, calculated as the average time from the June solstice until the September equinox, is about 93 days and 15Â½ hours. The average length of the southern hemisphere summer, calculated as the average time from the December solstice until the March equinox, is about 89 days.
In North America, summer is often fixed as the period from the summer solstice (June 20 or 21, depending on the year) to the fall equinox (September 22 or 23, again depending on the year). Therefore, Sept. 22 was the last day of summer and the beginning of the 2010 autumnal equinox, which officially began at 11:09 p.m. EST., the full moon having peaked the following morning at 5:17 a.m. EST which marked it as the first day of fall in the Northern Hemisphere.