Silver is the best conductor of heat. If you stir a cup of hot coffee or tea with a pure silver spoon, the handle gets hot very fast. Styrofoam is one of the worst conductors, therefore it is used as a heat insulator. Ceiling fans fight convection by blowing the hot air back down to the living space below. Most of the heat we get comes from the sun by radiation.
Sunlight amounts to about one kilowatt of heat per square meter of the earth's surface.
A Calorie is 1000 calories, and should always be called a kilocalorie, but it is common practice in food labeling and nutritional references to simply call it a Calorie. The food Calorie is the kilocalorie. A calorie is the quantity of heat required to raise the temperature of one gram of water, one Celsius degree. A Calorie or kilocalorie is the amount of heat required to raise the temperature of one kilogram of water one Celsius degree. Temperature is a measure of the concentration of heat, or the average amount of motion per molecule.