From Slime to Shine

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

From Slime to Shine

January 6, 2016

World's longest pearl necklaceA pearl is a beautiful, smooth, shiny ball from a weird place: the slimy inside of an oyster (or other two-shelled “mollusk”). If a grain of sand gets inside the oyster, the oyster avoids getting scratched by coating the sand with layers of “nacre,” or mother of pearl. That’s the same rainbow-shiny stuff that lines the shell itself. Coating the sand over and over takes a long time, and while any mollusk could make a pearl, only a few turn out so large and shiny. That’s why pearls are special and people make jewelry out of them. So Bedtime Math fan Amber J. asked, what is the world’s longest pearl necklace? Unbelievably, it’s more than a mile long! Made by Guangdong Ronghui Pearls Culture Co., the necklace has 316,474 pearls — that’s 316 thousand four hundred seventy-four. It also weighs almost 375 pounds, so if you want to wear it, you’ll need a truck driving behind you to carry the rest of it.

Wee ones: What shape is a pearl?

Little kids: If you hold 1 pearl on each tip of your fingers and thumbs, how many pearls do you have? Bonus: If you need 5 more to string them around your wrist, how many pearls will you need in total?

Big kids: If you added one more pearl to this 316,474-pearl necklace, how many would it have? See if you can remember the rest of the number!  Bonus: If each pearl is about 1/2 inch wide, how long would a 30-pearl stretch be?

 

 

Answers:
Wee ones: A circle (its cross-section, looking from the side), or in 3D it’s a “sphere.”

Little kids: 10 pearls.  Bonus: 15 pearls.

Big kids: 316,475 pearls.  Bonus: 15 inches.

And thank you Amber for this great math question and picture! If others of you out there have questions you’d like us to answer, just write to feedback@bedtimemath,org and let us know. We’ll give it a try!

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About the Author

Laura Overdeck

Laura Overdeck

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 while still in diapers, 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.

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