>What is the weight in pounds of a cubic foot of tap water? I do not >need high accuracy. To the nearest tenth of a pound would be fine. The density of water is 1.00000 gm/ml at 3.98 degrees C. To convert to weight at sea level, you can use the conversion ratios: 1000 ml / liter .03531467 cubic foot / liter .0022046226 pounds / gram Thus, the expression (1.00000 gm/ml) (1000 ml/liter) (.0022046226 pounds / gram) ----------------------------------------------------------- (.03531467 cubic foot / liter) yields the weight of water in the units you want. I'll let you do the math, just to keep you honest. You can find these expressions all over the web or in any chemistry or physics reference book. Best regards, Phillip Colla Research Associate: http://www.hwrf.org Photographer: http://www.oceanlight.com