Concrete Calculator - volume vs. weight. Calculator for weight of concrete amounts, between weight and volume equivalent measurements from lb^3, yd^3, cubic meter of concrete into mass measures in pounds, kilograms, tons.
Climbers use supplemental oxygen to give them an edge while pushing to the summit of a mountain like Everest at 8850 meters. At that altitude, the available oxygen is 33% of that at sea level. It is like running up a staircase while holding your breath 2 out 3 steps. To summit Everest without using any supplemental oxygen anytime on the climb is rare, it is estimated less than 100 out of the over 6500 summits have been accomplished in this pure manner.
Air gets 'thinner' with increasing altitude. That's why mountain climbers sometimes need bottled oxygen to breathe, and why it is so easy to get 'winded' while hiking in high mountains or even visiting someplace at elevation. Atmospheric pressure is around 1,014 millibars (14.7 pounds/inch 2) at sea level.t an elevation of 10 km (6 miles or about 30,000 feet), roughly the height of Mt. Everest, pressure drops to 265 millibars. That's less than 30% of the pressure at sea level! Both atmospheric pressure and the density of air decrease with altitude.