The temperature of a substance increases when the molecules making up the substance move at greater speeds. Rubbing an object causes the molecules of that object to move faster. Leaves of plants require light to form the green chlorophyll necessary for food-making and for their characteristic hue. If parts of a leaf are covered on both sides for a period of three days, the covered spots will be much lighter than the uncovered spots at the end of that period. A physician who was a member of a polar expedition had to make a few extractions of teeth and insert a few temporary fillings.
Some people believe that dental filings drop out in cold weather.
This doctor does not think that can happend even in the coldest weather, because inhaled cold air is immediately warmed, and the temperature of the teeth does not fall much. In a recent year three athletes in one area died from heat exhaustion and heat stroke. Schools in that ares now have installed weather instrunments that have been tested by the military. It shows a small ship filled with people who are enjoying playing games, eating, drinking, singing, and swimming. The hidden meaning of the picture is that people can become so involved in wordly pleasure that they have no concern for a real purpose or goal in life.