The start of spring is all about baby animals. So our fan Audrey C. asked, how does a caterpillar turn into a butterfly? Well, the change from caterpillar to butterfly is kind of gross, but also really amazing. First, the caterpillar eats nonstop, and grows really fast for about 2 weeks. The bug ends up weighing 200 times as much by the end of it! Then it attaches itself to a tree branch and sheds its skin, under which there’s a hard skin called a “chrysalis.” Over 2 more weeks, most of the caterpillar’s body turns into goop, and re-forms itself into a butterfly. Finally the butterfly crawls out and pops open its wings. After 4 weeks of sitting with nothing to do, that butterfly must be excited to fly.

*Wee ones:* Like all insects, a butterfly has 6 legs. Is that more or fewer legs than you have?

*Little kids:* If the caterpillar eats for 2 weeks, how many days is that? *Bonus:* If that all starts on a Monday, what’s the 5th day the caterpillar pigs out?

*Big kids:* If *you* started eating nonstop today (March 20), what’s the date of your 14th day of eating? (*Reminder if needed:* March has 31 days.) *Bonus:* What if you weighed 200 times as much after that as you do now? What would you weigh? (*Hint if needed:* Multiplying by 200 is the same as multiplying by 2, then by 100.)

*The sky’s the limit:* If the whole caterpillar “metamorphosis” (growth and chrysalis) takes exactly 4 weeks, and a caterpillar partway through that has 6 times as much time left as it’s already done, how many days of metamorphosis has the little guy done?

Answers:

*Wee ones:* The butterfly has more legs!

*Little kids:* 14 days. *Bonus:* That Friday.

*Big kids:* April 2. March 21 is the 2nd day, so March 31 is the 12th day, then we count forward 2 more. *Bonus:* Different for everyone…multiply your weight in pounds by 200.

*The sky’s the limit:* 4 days down, 24 days to go. Whatever part the caterpillar has lived already, it has 6 parts left of the same size, so there are 7 of those parts total…and 1/7 of 28 is 4 days.