Our Earth is a really, really big ball – it’s 8,000 miles wide. So how many cheeseburgers could we fit inside Earth if it were hollow? Balls work a lot like cubes: if a perfect cube is 2 times as wide as another, the bigger cube takes up 2 x 2 x 2 or *8* times as much space. Balls work the same way. We could count each burger as a 4-inch wide ball, and we know Earth is an 8,000-*mile* wide ball…let’s find out how many we can smush in there!

*Wee ones:* What shape is Earth?

*Little kids: *If you stack 8 cheeseburgers, then eat 1, how many do you have left? *Bonus: *How many 4-inch cheeseburgers do you have to line up in a row to make 1 foot (12 inches)?

*Big kids: *If 1 ball holds 27 times as much space (volume) as a 2nd ball, how many times as wide as the smaller ball is the bigger ball? (*Hint if needed:* What number times itself times itself makes 27? Very few numbers divide into it!) * Bonus: *How many 4-inch ball-shaped burgers can fit inside a 16-inch wide ball? (Don’t worry about gaps between them – assume they can squish and change shape to fill all space.)

Answers:

*Wee ones:* A circle from the side, and in 3D, a “sphere.”

*Little kids:* 7. *Bonus: *3 cheeseburgers, since 4 + 4+ 4 = 12.

*Big kids:* 3 times as wide, because 3 x 3 x 3 = 27. *Bonus:* 64, because you can fit 4 x 4 x 4 as many.