Did you know that you lose weight overnight?? Sure, when you exercise, you lose weight because you burn off fat. But in your sleep you lose water weight. Every time you breathe out, you lose water vapor as lots of teeny droplets. You also sweat out water through your skin. Grownups can lose more than a pound overnight, which is 2 cups of water. Try weighing yourself right before bed (after peeing) and again when you wake up (before peeing), and see what you find out!

*Wee ones:* Put a small amount of water in a cup, and drink it as you count your gulps. Now try putting about twice as much water, and count again taking the same size gulps. Did you take more gulps?

*Little kids:* If 2 cups of water weigh 1 pound, how much do 4 cups of water weigh? *Bonus:* How much do you weigh in pounds? If you then drink 1 pound of water, how much do you weigh on the scale afterwards?

*Big kids:* If you let out a breath every 5 seconds while sleeping, how many times do you breathe out in 1 minute? Count up by 5s if it helps! (*Reminder:* A minute has 60 seconds.) *Bonus: *Then how many times do you breathe out in 1 hour? (An hour has 60 minutes…and multiplying by 60 is like multiplying by 2 x 3 x 10.)

*The sky’s the limit:* And now…if you sleep 8 hours, how many times do you breathe out water overnight? (*A trick if needed:* 8 is 2 x 2 x 2, so to multiply a number by 8 you can double the number, then double it again, then double it again.)

Answers:

*Wee ones:* See how many gulps you get each time!

*Little kids: *2 pounds. *Bonus: *Different for everyone…find your weight in pounds, then add 1.

*Big kids:* 12 times. *Bonus:* 720 times.

*The sky’s the limit:* 5,760 times!