Hey, why are those stuffed animals floating around in the pool? Because they can! Their little boats are made of aluminum foil. A boat will sink just enough that the water it “displaces,” or pushes out of the way, weighs the same as the boat and its cargo. If the sides are too low, uh oh – it fills with water! So to float your own furry friends, just do the math. Weigh them first, then test your boat with the same weight of pennies or rocks. Then your friends will stay dry!
Wee ones: How many stuffed animals are floating in the pool? Look closely and count them!
Little kids: If the 3 lobsters each weigh 2 ounces, how much do they weigh together? Bonus: If the caterpillar weighs 9 ounces, how much more does he weigh than the lobster triplets?
Big kids: 11 pennies weigh about 1 ounce. If you need your boat to hold up a 5-ounce teddy bear, how many pennies does it need to be able to carry? Bonus: If you want to carry 5 of those teddy bears, and you’re testing your boat with 7-ounce rocks, how many rocks does it have to hold for you to know it can carry the bears?
Answers:
Wee ones: 4 stuffed animals.
Little kids: 6 ounces. Bonus: 3 more ounces.
Big kids: 55 pennies. Bonus: 4 rocks. The boat needs to hold 25 ounces, and 3 rocks will only prove that it can hold 21.
