The post Make a LEGO Gift Box appeared first on Bedtime Math.

]]>The holidays are coming! My kids like to think outside of the box (no pun intended) and use their LEGO items in different ways, so we decided to make LEGO gift boxes for some of our presents. I knew it would take more than ingenuity to pull this off. My boys would also need math to do the job right.

Grab a small toy and place it on a LEGO platform and then use bricks to build a base around the toy. Be sure to leave a little space for the toy to have wiggle room. If it’s too close to the toy and it shifts around later, it may be difficult to fit the toy back into the box when it’s complete.

As with wrapping presents the traditional way, it takes math to succeed. The base that was built around the toy is the perimeter of the box. Kids can count all the way around the base to determine what the perimeter of this box is in terms of LEGO units. The easiest way to do this is by counting the “studs,” the small cylindrical nubs that stick out of the bricks.

Remove the toy from the platform and use bricks to continue building up the walls. Assuming you’re sticking with basic box shape for your first build, will the perimeter change as the walls rise? What about the area of the box? When your walls are high enough to fit the toy, fill in the top so that your box includes a lid.

Now that you’ve finished your first build, challenge your kids to see if they can come up with a more creative box design.

Not only can these LEGO boxes be used to hide real holiday presents, they can be the gift itself.

For more awesome LEGO inspiration, be sure to check out the LEGO Balloon Car and The Best of Bedtime Math: LEGO Edition, and be sure to see this blog post for more gift-wrapping fun.

*Images courtesy of Beth Levine*

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]]>The post Countdown to Spring appeared first on Bedtime Math.

]]>Today is the winter solstice, when the southern half of Earth is tilted towards the sun and the top half, the north, is tilted away. For the US, UK and other northern places, it’s the coldest season because the sun is shining from lower in the sky. In fact, at the North Pole they’re getting no sun at all, day or night! Today is also the shortest day of the year, with the latest sunrise and earliest sunset. The good news is, starting tomorrow each day will have more daylight than the one before.

Do you find it hard to remember which day each season starts? Here’s the deal. The spring equinox always lands on March 20th — that one is easy. Winter usually starts on December 21st, except every 4th year it’s the 22nd, like next year. Summer usually starts on June 21st, except every 4th year it’s the 20th, like in 2016. And fall starts on the 23rd for 2 years, as this past fall and next year, then it will start on the 22nd for 2 years, then repeat the pattern.

*Wee ones:* If the sun sets today at 8 pm for you and sets at 6 pm in June, in which month do you get a later sunset?

*Little kids:* If your bedtime is always 10 minutes after sunset, and tonight the sun sets at 5:10 pm for you, when’s your bedtime today? *Bonus:* If spring starts 3 months from now, what month will that be?

*Big kids:* If today you got only 9 hours of sunlight, when was your sunrise and sunset if noon was right in the middle? *Bonus:* If winter starts on the 21st this year and on the 22nd this year, how many days do we wait for the next start of winter?

*The sky’s the limit:* If summer starts on June 20th only in leap years, like 2016, and on June 21st the rest of the time, on what date will it start in the year 2050?

Answers:

*Wee ones:* In December – so you must live south of the equator!

*Little kids:* At 5:20 pm. *Bonus:* In March.

*Big kids:* At 7:30 am and 4:30 pm. *Bonus:* 366 days – one more day than a full year.

*The sky’s the limit:* It will start on June 21st. 50 is not a multiple of 4, so 2050 can’t be, either.

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]]>The post The Most Beautiful Worm appeared first on Bedtime Math.

]]>When you look at the flowery blue thing in the photo, what do you guess that it is? Would you believe that it’s not a plant, but an animal — and worse yet, a worm? It *is* a worm, and scientists have nicknamed this crazy-looking creature the “Christmas tree worm,” since it looks a bit like a leafy fir tree. It lives on the Great Barrier Reef, a giant stretch of underwater coral off the coast of Australia. Coral is that beautiful spiky sea shape that looks like a plant itself, but is actually thousands of tiny, donut-shaped animals called coral polyps. They cluster together to make colorful, spiky branches. That means the Reef, which covers 133,000 square miles, is the world’s biggest cluster of living things! The Christmas tree worm hangs onto that coral but doesn’t eat it: it’s a filter feeder, using those fluffy tentacles to suck tiny creatures from the water and stuff them in its mouth. It doesn’t wave those around just to look pretty.

*Wee ones:* If this worm has 6 layers of spiraling tentacles and its friend has 8, which one has more?

*Little kids:* If you scuba dive to photograph this worm at 300 feet deep, and so far you’ve swum 100 feet down, how much deeper do you have to swim? *Bonus:* The Reef covers 133,000 square miles, while the state of California covers 164,000 square miles. Which one is bigger?

*Big kids:* If you scuba dive at the Reef and swim 200 feet down, then 90 feet up, and then 10 feet back down to take an underwater photo, how deep are you? *Bonus:* The Reef is home to 125 species, or types, of sharks and rays. If there are 4 times as many types of sharks as rays, how many shark species are there?

Answers:

*Wee ones:* The neighbor, with 8 layers.

*Little kids:* 200 more feet. *Bonus:* California is bigger, but not by much!

*Big kids:* 120 feet down. *Bonus:* 100 shark species (and 25 rays).

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]]>The post Following Your Favorite Shark appeared first on Bedtime Math.

]]>When you watch squirrels or chipmunks run around your neighborhood, do you ever wonder exactly where they go? How many bushes, trees and buildings do they visit? Do they stay nearby, or do they get bored and visit other streets? The answers get even more interesting for animals that swim or fly, since they can travel a lot farther. A great white shark named Lydia now has lots of fans following her every move on the Ocearch website. Scientists stuck a little gadget on her fin called a satellite tracker. No matter where she swims, that tracker sends a message to the satellite, which then marks where she is on a map. We can click on the map and see red and blue dots showing where this 2,000 pound, 14-foot long shark is swimming, and how far she swims every few weeks. Great white sharks can be dangerous, so it feels good to chase them instead of them chasing us — and to do so from very far away!

*Wee ones:* Whose body is longer, yours or Lydia’s? How “long” are you in feet?

*Little kids:* If the map shows a straight line of 5 blue dots for Lydia, with 100 miles between each of them, how far did she swim from the 1st to the 5th dot? *Bonus:* How much longer than you is Lydia, if she’s 14 feet long? (You can round your height to the nearest foot.)

*Big kids:* If the map tracks 20 sharks and shows 3 dots for each, how many dots are there on the map? *Bonus:* If Lydia’s tracker “pings” (sends a signal) every 4 hours, how many pings at most can the scientists get from 7 am to 11 pm?

Answers:

*Wee ones:* Body length is different for everyone, but Lydia is longer than any of us!

*Little kids:* 400 miles, since the 5 dots have 4 spaces between them. *Bonus:* Different for everyone…subtract your height in feet from 14.

*Big kids:* 60 dots. *Bonus:* 5 pings. It’s a 16-hour period, but you can get a ping at 7 am, plus the 4 more at 11 am, 3 pm, 7 pm and 11 pm (this in math is called the “fencepost problem,” when you have to count the endpoint.)

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]]>The post Crazy Space Line-up appeared first on Bedtime Math.

]]>When we look at the stars in the night sky, we see that our planet Earth isn’t the only ball of rock whizzing through space. For one thing, there are 7 other major planets gong around the Sun – Mercury, Venus, Mars, etc. – many of which we can see without using a telescope. Then we have the Moon, our nearest neighbor. The Moon sounds like it’s far away, almost a quarter million miles, but someone figured out that all the other planets could fit perfectly lined up in that space! They’d leave just about 5,000 miles extra, so even Pluto could fit if we still counted it as a major planet. We also love this photo showing the hugeness of Jupiter: Earth is 8,000 miles across, which feels pretty big, but Jupiter is more than 88,000 miles across. North America looks so teensy next to Jupiter’s stormy Red Spot. It’s a great reminder that we may not be very big, but at least we aren’t alone.

*Wee ones: *What shape are the Earth, the Moon, and our planet friends?

*Little kids:* How many objects can you count in the photo of Earth, Moon, and the planets? *Bonus:* Mercury is about 3,000 miles wide, Venus is about 7,000, and Mars is about 4,000. How much of that line-up do those 3 cover together?

*Big kids:* Jupiter is almost 300,000 miles around at its widest point. How many 3,000-mile-wide Americas could you wrap around Jupiter? *Bonus:* If Earth is 8,000 miles wide and Jupiter is 88,000 miles wide, how many times as wide is Jupiter?

*The sky’s the limit:* If you wanted to line up the 4 gas giants (Jupiter, Saturn, Uranus and Neptune) in the last 4 slots but in some other order, how many other ways could you line them up?

Answers:

*Wee ones:* They are spheres, another word for ball. From the side they also look like circles.

*Little kids:* 9 objects. *Bonus:* 14,000 miles, nowhere near the width of the next biggest planet after Earth (Neptune at over 30,000 miles).

*Big kids:* 100 of them. *Bonus:* 11 times as wide.

*The sky’s the limit:* 23 other ways. If you keep Jupiter first, there are 3 planets that can go in the next slot; for each of those 3 choices you can put either of the remaining 2 planets in the next slot, leaving the last one for the last spot. That gives you 3x2x1 or 6 orders that put Jupiter first. But you can do this with any of the 4 planets coming first, so that gives you 4x3x2x1, or 24 orders. The one shown here is one of them, so that gives us 23 other ways.

And thank you Emily B. for sending these amazing photos!

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]]>The post So You Wanna Be A…Tightrope Walker appeared first on Bedtime Math.

]]>Nik Wallenda has been walking on tightropes and setting world records for pretty much his entire life. His most recent record setting stunt was for the highest blindfolded tightrope walk ever. We couldn’t believe our eyes when he sat down to talk with us!

*BTM: I know in your case, you were pretty much born into tightrope-walking, since your family’s been performing for generations. What was it like growing up as a Flying Wallenda?*

Nik: The funny thing is, I was walking the wire before I was born – my mom was still tightrope walking when she was 6 months pregnant with me. But I really started walking the wire on my own legs at around 2 years old, on a rope about 2 feet off the ground. I never did anything up high until I was about 13 years old, and then I walked at about 30 feet, and from there, I kept going higher and higher.

*BTM: How you think up world-record setting stunts that you can pull off?*

Nik: Most of the time it just comes to me – I’ll be sitting there at night, or even sleeping, and I’ll think of a stunt that would be an amazing walk. The blindfold walk actually happened because I was having Lasik surgery – I wondered if I would still be able to do what I do if I lost my vision. So I started to challenge myself to train with my eyes closed, and eventually was able to prove that I could do it, and broke a world record doing the highest blindfold walk ever.

*BTM: And once you have an idea for a walk, how do you use math to make it happen?*

Nik: There’s a lot of mathematics, science and engineering in walking a wire, and I have an amazing team of engineers that help me plan my walks. I go to them with an idea for a walk, and they go out there with a survey crew. The survey crew uses geometry, trigonometry, all kinds of fun math so that they can tell me the height of the buildings, the space between the buildings, and the incline of the wire between those two buildings. Then we can set up a wire at that incline so I can test it out, and we can adjust the tension and sag in the cable based on those tests.

*BTM: And then when you’re walking, is there math in the speed you need to move at?*

Nik: You know, we’ve gotten all the math worked out beforehand, so there’s not a lot of math *as* I’m walking –

*BTM: We would be counting the steps until it was over, because we’re not nearly as comfortable with heights as you are.*

Nik: (laughs) Yeah, that makes sense. One math skill I have to use while walking the wire is accounting for wind gusts. I’ve trained in winds of up to 120 MPH on the beach in Florida, where I live. When we’re planning a walk, we find out what the strongest winds are going to be on top of buildings based on averages for that time of year, and then we plan for the wind to be worse than average.

*BTM: So if a kid wants to grow up and set world records with stunts, what type of math will they need to know? *

Nik: I encourage kids to do whatever they set their minds to. A lot of any job is training and preparation, and in my line of work, engineering comes into every aspect of it. I’ve got friends like Robbie Madison and Travis Pastrana that do amazing jumps, and there is so much math in those ramps, with calculations of speed they have to go on their motorcycles, angles of the ramp to clear gaps, and the force that they’re going to take when they land. So the math used in engineering is very important for any daredevil, for sure.

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]]>The post Big Bunny appeared first on Bedtime Math.

]]>We usually think of rabbits as small, cute, furry pets. But they can grow big, and the world record-breaking big bunny is one giant bundle of fluff. Ralph, a Continental Giant rabbit, weighs 55 pounds! Continental Giants are a “breed” or type of bunny, but even with that name they usually weigh 26 to 30 pounds at most. Ralph obviously thought that wasn’t enough — nor did his parents, who were huge themselves. Each of them held the record for biggest bunny at some point, too. Like most bunnies, Ralph likes to eat carrots, cabbage, cucumber, corn on the cob, crackers, and even a few foods that don’t begin with “c,” like apples and broccoli. He eats so much of them that it costs $90 per week to feed him. That said, if you want a fluffy live pet that’s as big as you are, Ralph and his giant friends could be a good choice.

*Wee ones:* If Ralph likes carrots, cabbage, cucumber, corn, and crackers, how many c-word foods does he like?

*Little kids:* If Ralph eats 2 carrots and twice as many crackers for breakfast, how many food items does he eat? *Bonus:* If you wanted him to have as many carrots as those crackers, how many more carrots would you need to give him?

*Big kids:* Ralph weighs 55 pounds. How does that compare to you – which of you weighs more, and by how much? *Bonus:* If you eat just $10 more of food per week than Ralph does, how much does it cost to feed the two of you?

Answers:

*Wee ones:* 5 c-foods.

*Little kids:* 6 food items, since it includes 4 crackers. *Bonus:* 2 more carrots.

*Big kids:* Different for everyone! Subtract your weight in pounds from 55, or subtract 55 from your weight. *Bonus:* $190 per week, since you eat $100.

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]]>The post “Chocolate-Covered Anything” Day appeared first on Bedtime Math.

]]>Chocolate is so delicious that it can taste just as good with other foods as it does by itself. Just about anything tastes good when dipped in gooey, melted chocolate — well, not *anything*, broccoli probably doesn’t work, but a lot of other foods do. That’s why we celebrate Chocolate-Covered Anything Day, which is today. The chocolate shoppe La Maison du Chocolat took things a step further by making a Chocolate Tree of Wonder for the holidays. It’s a dark chocolate spiral of 25 layers, decorated with nuts, pine cone shapes, droplet-shaped ornaments of “blonde” chocolate, and even some gold foil (you can actually eat small amounts of gold). The tree takes so much work to make that they charge $1,150 for it! The good news is, if that sounds like too much, you can melt your own chocolate and dip pretzels, marshmallows or strawberries, and celebrate today on your own.

*Wee ones:* What shape would you call this chocolate tree?

*Little kids:* There are 10 blonde ornaments in or on the tree. If you eat 3 of them, how many are left? *Bonus:* If each of the 10 ornaments has 3 chocolate-covered nuts inside, how many nuts do they have together?

*Big kids:* If you buy one of these trees and stick 2 chocolate-covered strawberries onto each of the 25 layers, how many strawberries do you add? *Bonus:* If you actually add them just to every 4th layer, what’s the greatest number of layers that can be strawberrified?

*The sky’s the limit:* If you’re the confectioner at La Maison, and you want to stick almonds on every other layer, walnuts on every 3rd layer, and gold foil on every 4th layer, starting with the top layer for all 3, how many other layers will get all 3 new ingredients?

Answers:

*Wee ones:* A cone. In profile (from the side), it also looks like a triangle.

*Little kids:* 7 ornaments. *Bonus:* 30 nuts in total.

*Big kids:* 50 strawberries. *Bonus:* 7 layers, if you start at the very top. Instead of 4, 8, 12, etc. you’re fitting in layer 1 along with 5, 9, 13, etc.

*The sky’s the limit:* The 13th and 25th layers. Because you’re starting on the first layer, all foods will end up on numbers that are 1 more than the multiples. So you can solve this for the regular multiples – what numbers are divisible by 2, 3, and 4? That would be the 12th and 24th layers, so if you start at the top, it will instead by the 13th and 25th layers that get all three.

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]]>The post Light a Candle appeared first on Bedtime Math.

]]>Tonight’s sundown marks the start of Hanukkah, the Jewish holiday also known as the Festival of Lights. Hanukkah lasts for 8 nights and 8 days, with traditions including lighting the menorah each night, enjoying special foods and exchanging gifts. The most central ritual each night is the lighting of the menorah, a candelabrum that holds 9 candles in total. On the first night, one candle (the shamash) is lit, and is then used to light one additional candle. On the second night of Hanukkah, yet another additional candle is lit, until the whole set of 9 is lit on the final evening. When you count up the candles, you see that you use a lot of them to keep the menorah burning bright.

*Wee ones:* If Hanukkah lasts 8 nights, how many more nights after tonight will you light candles to celebrate?

*Little kids:* If the 8 regular candles are divided evenly on either side of the shamash, how many candles are on each half? *Bonus:* If you light the candles at 6 pm and they burn for 7 hours, at what time will they finally melt to the bottom? (Hint if needed: midnight is 12:00, at which point the numbers on the clock start over.)

*Big kids:* If you have 1 menorah at your house, 1 at your aunt and uncle’s house and 1 at your grandparents’ house, how many candles can those 3 menorahs hold in total? *Bonus:* On the first night, you light the center candle plus 1 more, then the next night you light the center candle plus 2 more — so by then you’ve lit 5 candles (2 the first night, 3 the second night). How many candles will you need for all 8 evenings in total?

Answers:

*Wee ones:* 7 more nights.

*Little kids:* 4 candles on each side. *Bonus:* 1:00 in the morning.

*Big kids:* 27 candles. *Bonus:* 44 candles.

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]]>The post Laughing As Exercise appeared first on Bedtime Math.

]]>Did you ever wonder what your face has to do to laugh? It’s actually a lot of work, right? since almost every part of your face moves. Your face has about 43 “muscles,” those pieces of your body that stretch and scrunch up to move different parts of you. Some say it takes fewer of them to smile than to frown, so you might as well smile instead of walking around grumbling. But others say it’s more work to smile. So which is it? It turns out that it’s not so clear. For one thing, people have *around *43 facial muscles, but can have up to 15 more than that or 15 fewer. And we know some people smile big and give lots of muscles a workout, while other people barely lift a lip. Someone did count out that you need at least 5 pairs of muscles, or 10 total, to raise the corners of your mouth. And if you’re laughing big, you’re using much more of your face than that — not to mention the rest of your body if you’re really rolling on the floor.

*Wee ones:* If someone’s telling jokes and you laugh at 7 of them and your friend laughs at 5 of them, who laughed at more jokes?

*Little kids:* If you smile, then frown, then smile and frown and keep going, what’s the 7th face you make? *Bonus:* What’s the 17th?

*Big kids:* If you use 40 out of 43 muscles to laugh but just 20 to smile, what’s the smallest possible number of muscles that do both? *Bonus:* If you use 20 of your 43 muscles to stick out your tongue and 30 to laugh, what’s the biggest possible number of muscles that you don’t use for either one?

Answers:

*Wee ones:* You laughed at more.

*Little kids:* A smile, like all the odd numbers. *Bonus:* Also a smile, since it’s 10 faces later; you’ll do 5 more sets of smile-frown.

*Big kids:* 17, since there are only 3 out of those 20 muscles at most that can differ. *Bonus:* 13 muscles, if you use all 20 tongue-sticking ones to laugh, too.

And thank you Xanthe M. for this awesome topic!

The post Laughing As Exercise appeared first on Bedtime Math.

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