Just curious- converting space to water capacity???

Question

I've been out of school a long time. What is the formula for calcuating how much water a space -like an empty aquarium would hold water / volume wise? And, if I may, how much does 1 gallong of water weigh?

I know I learned this; yet I can't seem to locate it in my memory banks... this is happening a LOT lately. Mostly, it's due to perscribed medications so, it's as amusing as it is frustrating,

I do rate answers & pick a winner. Thank you for your time & help. Thank You God, Creator of the universe and all that exists, for continuing to bless, enrich & heal all those who love Your Son, Jesus and those who will in the near & distant future become part of Your Family. You ROCK! To God be all the glory LOVE YOU!

Answer 1

1 cu-ft of water contains 7.48 gal

1 gal of water weighs 8 pounds

cu-ft = Length(inches/12) x width(inches / 12) x height inches /12)

ex: measure a fishtank:

Length= 26.75 in / 12=2.23ft

width= 20 in / 12=1.67 ft

height= 18 in / 12=1.5 ft

The volume= 2.23 ft x 1.67 ft x 1.5 ft = 5.59 cu-ft

Assume the tank is filled all the way up : 7.48 gal/ cu-ft x 8 pounds / gal = 334.5 pounds

Thats full but the tank may be filled to 15 in not 18 so figure the volume based in 15 in ......