Every day we stand up and walk around on the ground. That’s because we aren’t fish. But 3/4 of Earth is covered with water. So our friend Parker M. asked, how much does the ocean weigh? Well, water’s really heavy: if you had a box 1 foot wide, 1 foot long and 1 foot tall filled with water, it would weigh about 62 1/2 pounds! Scientists’ best guess is that there are 326 million cubic miles of water, meaning boxes a whole mile wide, a mile long and a mile tall. Each side of a cube that size is 5,280 feet long, so there are 5,280 x 5,280 x 5,280 little 1-foot boxes in each of those cubic miles…we get 47,986,532,352,000,000,000 of those, or nearly 48 quintillion. Multiply by 62 1/2 pounds for each of those, and that weighs 3 sextillion pounds. We’re glad we could figure this out without weighing it cup by cup!
Wee ones: Plug a sink, turn on the water while you count to 5, then turn it off. Is the sink a little bit full, half full, or totally full?
Little kids: If you drink a cup of water at breakfast, then lunch, then dinner, plus 3 more cups in the afternoon, how many cups do you drink each day? Bonus: How many more would you need to drink a half-gallon (8 cups)?
Big kids: 1 gallon of water weighs about 8 pounds. How many gallons of water match your weight? (Hint if needed: 8 is 2 x 2 x 2, so to divide by 8, you just cut in half 3 times in a row.) Bonus:How much does a 40-gallon bathtub of water weigh, if each gallon weighs about 60 pounds?
Answers:
Wee ones: It should probably be only a little bit full.
Little kids: 6 cups. Bonus: 2 more cups.
Big kids: Different for everyone…divide your weight by 8, or see how many 8s you need to add up to match your weight. Bonus: 2,400 pounds!
