The troposphere contains 75 percent of atmosphere's mass-on an average day the weight of the molecules in the air is14.7 lb..(sq. in.)- and most of the atmosphere's water vapor.ater vapor plays a major role in regulating air temperature because it absorbs solar energy and thermal radiation from the planet's surface. The troposphere contains 99% of the water vapor in the atmosphere. Water vapor concentrations vary with latitudinal position(north to south).
Proper is different from typical or average. Average mantel height is about 54 above the hearth extension. Proper depends on the fireplace size, required clearances and the aesthetic desired, which can vary widely. These are both proper mantel heights: This one's about 48 high.
And a reminder, placing your TV above the fireplace may void your TV's warranty! A television on top of a low credenza provides the perfect height for comfortable viewing. Experts recommend the top of the screen should be between 15-35 degrees from the horizontal plane of your eye level (aim for 15 degrees), which means a flat panel mounted above a fireplace isn't just an eyesore, but sore muscle inducing. â