Some nights our Moon is just a half-circle in the sky, or a thin crescent (C shape). But tonight we have a full moon! Why does this happen? The Moon takes about 29 days to go around Earth, and when it’s on the opposite side of Earth from the Sun, we see its shiny side. When it’s between us and the Sun, its shiny side is away from us, so we can’t see it. That’s a “new moon.” When the Moon is “next to” Earth, we see half of it lit. What’s really cool is that whatever part of the moon is lit, that’s the fraction of the night we can see it! A full moon is up all night, and a half moon is up for half of it. That bright ball is a quarter million miles away from us, so our friend Isaac I. asked, how many pencils would we have to line up to reach the Moon? It’s a giant number – check out the math below!
Wee ones: Tonight the Moon looks like a full circle. Can you see other circle shapes in your room?
Little kids: The Moon looked pretty full last night also, and will tomorrow night, too. If today is Friday, what day was it yesterday, and what day is tomorrow? Bonus: The new moon will be 15 days from today, which is Friday. What day of the week will that be?
Big kids: How do you write “1 million” all in numbers? Bonus: This is a big one…If our pencils are a little shorter than 1 foot, we can estimate that a mile (5,280 feet) can fit 8,000 pencils. How many pencils does it take then to reach a quarter million miles? (Hint if needed: How many would fit in 1 million miles? and then work from there.)
Wee ones: Different for everyone…you might find clocks, balls, wheels on toy cars, eyes on stuffed animals. See what else you find!
Little kids: Yesterday was Thursday, and tomorrow is Saturday. Bonus: On a Saturday. 2 weeks would bring us to another Friday, and this is 1 day more than that.
Big kids: 1,000,000. Bonus: 2 billion pencils (2,000,000,000) since 1 million miles would hold 8 billion (8,000,000,000).
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.