The post Krush of K’Nex appeared first on Bedtime Math.

]]>We are loving this video of the world-record K’Nex ball roller coaster, and you probably will, too. K’Nex are those cool, colorful snap-together sticks. As with Lego or Tinkertoys, you can add on more and more pieces to make giant shapes and structures. This one, built by Austin Granger, uses more than 126,000 pieces! Balls travel up little elevators, roll down wavy ramps, and ride ferris wheels, all of which together fill a huge warehouse. Blinking lights line some of the paths to add pizzazz. There’s even one of those toilet-bowl drains where the balls circle around and around before going down the hole. See if you can follow all those balls, and guess how many sticks each one actually touches!

*Wee ones:* The ball “elevators” run up and down a straight line. See if you can spot any straight up-and-down lines in your room.

*Little kids:* If you snap on a blue K-Nex, then a red, then a white, then a blue to start the pattern again, what color is the 6^{th} stick? *Bonus:* How many sticks do you snap together to make a cube? If needed, look at a rectangular box-shaped object to see the edges!

*Big kids:* If the ball takes 14 seconds to roll to the left on a ramp, then just 1/2 that time to roll back to the right, how long does that whole back-and-forth take? *Bonus:* If a new ball starts at that first spiral every 10 seconds, how many balls will start the trip during a 5-minute stretch — including the very first at 0 seconds?

*The sky’s the limit:* If the 126,000-piece ramp uses equal numbers of red, blue, green, white, and black sticks, but 4 times as many yellow sticks as red, how many sticks of each color does it use?

__Answers:__

*Wee ones:* Answers might include the vertical (up and down) edges of windows, doors, dressers and other furniture, and stripes in curtains.

*Little kids:* A white stick. *Bonus:* 12 sticks: 4 on the bottom, 4 up-and-down side, and 4 around the top.

*Big kids:* 21 seconds, since it takes 14 seconds there and 7 back. *Bonus:* 31 balls. There are 6 per minute starting at 10 seconds in, then you add 1 more to count the very first.

*The sky’s the limit:* 56,000 yellow sticks, and 14,000 of each of the other 5 colors. If you have equal numbers of those 5 colors and then 4 times as many yellow as any of them, then each red stick has a blue stick, a green, a white, a black and 4 yellow sticks with it, making a “set” of 9. There are 14,000 of those sets in 126,000, so there are 14,000 of each of the small colors and 4 times as many as that for yellow.

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]]>The post Donuts Gone Bonkers appeared first on Bedtime Math.

]]>When you stick one yummy food inside another, you get more yumminess. We have pigs in blankets (hot dogs wrapped in dough), chocolate croissants (chocolate inside buttery bread), and the “turducken,” a Thanksgiving dish where chicken meat is stuffed inside duck meat inside a turkey. Now we have the “donut turducken.” While testing donut recipes, chef Kim Laidlaw stuffed an apple fritter (fried apple pieces) inside pudding inside a donut, which she then coated with chocolate frosting and sprinkles. Cinnamon-flavored apples don’t sound like a great match for chocolate…but it’s probably tastier than stuffing it with duck!

*Wee ones:* If you stuff apples inside pudding inside a donut covered in frosting, how many different foods have you mixed up?

*Little kids:* If you stuff 8 chunks of apple in one donut and 11 in another, which has more apple? *Bonus:* If you stick 3 apple pieces in each donut, will 7 pieces be enough for 2 donuts?

*Big kids:* If guests are visiting you an hour from now, and it takes you 20 minutes to fry the apples, 20 minutes to fry the donuts, and 16 minutes to stuff them, can you make the donut turduckens in time? *Bonus:* If you make 8 donuts in that time (56 minutes), how many minutes did each donut turducken take on average?

Answers:

*Wee ones:* 4 foods.

*Little kids:* The donut with 11 chunks. *Bonus:* Yes! since you need only 6 pieces.

*Big kids:* Yes: they will take 56 minutes, and guests are coming in 60. *Bonus:* 7 minutes each.

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]]>The post Dogs in Charge appeared first on Bedtime Math.

]]>Dogs may seem like they’re just fun, fluffy goofballs. But some dogs actually work real jobs, such as police dogs. They’re called the K9 unit, since it sounds like “canine,” which means “dog-related.” K9 dogs are usually German shepherds, like these dogs here, and they get lots of excitement. They help chase down bad guys, sniff for drugs, and rescue missing people. The dogs can’t talk, so they have to show what they think by doing the right action, like barking or sitting very still next to what they’ve found. These dogs are working on behaving well, by watching a cat without chasing it. K9 dogs train for a few hours every week, and can work for about 6-9 years. Then they can start chasing cats again.

*Wee ones:* Are there more cats or dogs in the photo?

*Little kids:* If a dog trains until age 3 and then works for 7 years, how old is the dog when he stops working? *Bonus:* If an 11-year old dog has worked for 9 years, how old was she when she started?

*Big kids:* If a dog starts training at 9:30 am each day for 8 hours straight, at what time does training end? *Bonus:* If 1/5 of the 15 dogs in the photo just can’t stand it any more and start chasing the cat, how many dogs sit still like they should?

*The sky’s the limit:* If in self-control training there are 5 times as many dogs as cats, and there are 24 animals in total, how many of each animal do we have?

Answers:

*Wee ones:* More dogs!

*Little kids:* 10 years old. *Bonus:* At 2 years old.

*Big kids:* At 5:30 pm. *Bonus:* 12 dogs, since 3 of the 15 dogs pounce.

*The sky’s the limit:* 20 dogs and 4 cats. If there are 5 times as many dogs as cats, then there are 6 total “sets” of animals that add up to 24. That means each set has 4 animals, giving us 1 set of 4 cats, and then 5 times as many dogs, or 5 x 4 = 20.

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]]>The post The People Flying over Your Head appeared first on Bedtime Math.

]]>Have you ever watched an airplane in the sky, and wondered how many people are in there, and where they’re going? Now multiply that by all the planes in the air at any time. This webpage made a 2-minute video showing all the planes that flew over the Atlantic Ocean in 1 day: over 2,500 flights in 24 hours! Air traffic controllers tell the pilots where to fly so they don’t run into each other. So the sky is divided into “tracks” for planes to follow, almost like lanes on a highway. When you run the numbers, you’ll see that there are way more people on that highway than you might think.

*Wee ones:* If you’re the 3rd person to get on a plane, how many people got on before you? Hold up your fingers to show 3 people getting on a plane!

*Little kids:* Planes are spaced to land every 10 minutes. What numbers would you say to count down those 10 minutes? *Bonus:* If 400 flights fly during each busy hour in the morning, how many planes fly in a 2-hour stretch?

*Big kids:* If 7,000 people fly in the morning and twice as many fly during the afternoon, how many fly that stretch in total? *Bonus:* If there were exactly 2,500 flights and they each filled up with 100 passengers, how many people flew over the ocean that whole day?

__Answers:__

*Wee ones:* 2 people before you.

*Little kids:* 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. *Bonus:* 800 flights.

*Big kids:* 21,000 people. *Bonus:* 250,000 people – a quarter of a million!

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]]>If you could repaint your room, and could go as crazy as you wanted, what colors would you use? Of course, the fancier you get, the more carefully you have to plan.

The post A Brush with Danger appeared first on Bedtime Math.

]]>Sometimes you look at your everyday life and decide you need a change – a big change. And one way to get that is to repaint your bedroom. Lots of colors, lots of eye-hurting patterns – something that will make a statement. If you could repaint your room, and could go as crazy as you wanted, what colors would you use? Of course, the fancier you get, the more carefully you have to plan.

*Wee ones: *If you paint 4 walls and 1 ceiling all in different colors, how many colors of paint do you need?

*Little kids: *If you repaint your room like a jungle, and you need 4 quarts of Macaw Yellow and 4 quarts of Coconut Green, how many quarts of paint do you need? *Bonus: *If there are 4 quarts in 1 gallon, how many gallons of paint is that?

*Big kids: *You’ve decided to paint giant Lifesavers all over the walls. If a gallon of paint is enough for 7 Lifesavers, how many candies can you paint with 3 gallons? *Bonus:* Of those Lifesavers, if you paint 6 bright red and for the rest you paint equal numbers of yellow, orange and green, how many orange Lifesavers do you paint?

*The sky’s the limit: *In the middle of the night you secretly paint your room with glow-in-the-dark stripes – which is good, because you can see what you’re doing. If you need 2 gallons of neon green, 3 times as much silver as green, and 4 times as much ultraviolet as silver to fill the walls, how many total gallons of paint do you need?

Answers:

*Wee ones:* 5 different colors of paint.

*Little kids:* 8 quarts. *Bonus: *2 gallons.

*Big kids: *21 giant Lifesavers. *Bonus: *5 orange, because you have 15 Lifesavers left and 3 colors for them.

*The sky’s the limit:* You need 32 gallons: 2 neon green, 6 silver, and 24 ultraviolet.

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]]>The post How Birds Make Movies appeared first on Bedtime Math.

]]>We all love to take pictures and videos of ourselves. Well, it looks like birds want to try it, too. In this wacky video, an eagle snatches a hiker’s videocamera and starts flying around with it, then finally puts it down and poses for a selfie (as we see here). Since the camera is sailing through the air, we get an amazing view of the mountains and scenery, as well as some feathers from the bird’s wings. The eagle also pecks at the camera, wondering if it’s something yummy to eat. Hopefully he found a better snack after that.

*Wee ones:* Other than the ceiling, what’s the highest thing in your room where an eagle could land?

*Little kids:* If the eagle took the camera for 1 minute and the hiker had used it for 1 hour, who used it for longer? *Bonus:* The eagle carries the camera for 1 minute and 1 second. Since a minute has 60 seconds, how many seconds is that in total?

*Big kids:* If the eagle filmed you for 11 seconds, then you filmed the eagle for twice as long, how much video would the two of you have in total? *Bonus:* We see the eagle’s wings about twice per second when the bird and camera start flying. How many wing flaps is that in 1 minute? (*Reminder if needed:* A minute has 60 seconds.)

*The sky’s the limit:* If the hiker and the eagle start 250 feet apart, and as they move towards each other the eagle is flying 4 times as fast as the hiker is running, how far from their starting points do they meet?

__Answers:__

*Wee ones:* Answers might include a bedpost, the top of a lamp, or the top of a window.

*Little kids:* The hiker used it longer. *Bonus:* 61 seconds.

*Big kids:* 33 seconds. *Bonus:* 120 wing flaps.

*The sky’s the limit:* 50 feet from the hiker’s starting point, and 200 feet from the eagle’s starting point. If the eagle moves 4 times as fast, the eagle covers 4 hiker chunks of distance, so together they’ll travel 5 of those chunks. 1/5 of 250 feet is 50, so the hiker moves 50 and the eagle moves 4 times that.

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]]>The post Karate Chop! appeared first on Bedtime Math.

]]>Have you ever seen someone chop a wooden board in half with her bare hand? Ouch! How do people do that? Well, for one thing, your bones are 40 times as hard as concrete. To top that off, even new karate students can move their hands at up to 13 miles an hour — and pros can reach 30 miles an hour, even smashing through cement blocks. Karate is a Japanese “martial art,” a sport where you use your arms, legs, and the rest of your body to protect yourself. Punching, kicking, and yes, those karate chops are all special skills you can learn. If you’d like to wow your friends, take those concrete bones and put them to work!

*Wee ones:* If you chop a wooden board, a cement block, and a small tree trunk, how many things did you karate chop?

*Little kids:* If you chop a board into 2 pieces, then chop each of those pieces into 2, how many little pieces do you have now? *Bonus:* If you break only every 3rd board you try, starting with the 3rd, what happens on the 9th board?

*Big kids:* If you chop at 20 feet per second, you can break a 1-inch thick board. But a black belt instructor can chop at 46 feet per second. How much faster is that? *Bonus:* If your hand is tough enough to break 1 board every 5 minutes, how many can you break in 1 hour if the first board breaks at 5 minutes? (Reminder if needed: An hour has 60 minutes.)

Answers:

*Wee ones:* 3 things.

*Little kids:* 4 pieces. *Bonus:* You break it! 9 is a multiple of 3.

*Big kids:* 26 feet per second faster. *Bonus:* 12 boards, since there are 12 5-minute chunks in an hour.

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]]>The post Making Toys out of Chocolate appeared first on Bedtime Math.

]]>The 3D printer is a pretty exciting machine. Instead of squirting ink onto paper, it prints with hot melted plastic, which stacks up in layers to build shapes like cubes and spirals. So it didn’t take long for someone to try putting chocolate in the printer. Our fan Chad R. told us about Hershey Company’s CocoJet which prints with melted chocolate. As you can see in this video, the arm that holds the chocolate moves side to side and back to front to squirt the chocolate in the right spots. If you switch from dark chocolate to milk or white, you can even make designs in different “colors.” The question is, will you save that cool shape, or eat it?

*Wee ones:* What shape are the sides on that chocolate toy?

*Little kids:* If you print a stripey chocolate with 2 layers of dark chocolate, 2 layers of milk chocolate, then 2 layers of white, how many stripes does it have? *Bonus:* If you bite off 4 layers, how many are left?

*Big kids:* If you can print a mini chocolate soccer ball with 4 ounces of chocolate, how many ounces would you need to print 5 soccer balls? *Bonus:* How many complete balls could you make out of 2 pounds 6 ounces of chocolate? (Reminder: A pound has 16 ounces.)

*The sky’s the limit:* The chocolate shape shown here is an icosahedron: it has 20 identical triangle sides, where all edges and angles are equal. How many edge bars does the printer have to print in total?

Answers:

*Wee ones:* Triangles.

*Little kids:* 6 layers. *Bonus:* 2 layers.

*Big kids:* 20 ounces. *Bonus:* 9 balls, since you have 38 ounces and 36 is the biggest even multiple of 4 within that.

*The sky’s the limit:* 30 bars. If the triangles all stood alone without touching, they’d have 60 edges in total (20 x 3). But every edge is shared by 2 triangles, so together the 20 triangles need only half as many edges as that.

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]]>The post Giving the Green Light appeared first on Bedtime Math.

]]>When we drive on the road, we can’t all just go every which way. We have to stay on one side, and wait our turn where roads cross. Stop signs help, but really busy crossings need traffic lights. The traffic light, that cute red, yellow and green trio, was patented (made official as an invention) in 1923. Actually, the very first electric traffic light was invented in 1912 by Lester Wire, a policeman in Utah fed up with all the traffic. Wire borrowed the idea of railroad signals to make a traffic light, which had just red and green for stop and go. Then in 1920, Detroit cop William Potts built one with 3 colors (red, orange and green). Now we have LED traffic lights, but those don’t get warm enough to melt snow. As you see here, people have tried other designs, like this funny dial one from Australia, but the three-color light is what keeps most of us from crashing into each other today.

*Wee ones:* If a traffic light has a red light, a yellow, a green, and then a green left-turn arrow, how many lights does it have?

*Little kids:* Lester Wire’s light had 4 sides with a red and green light on each side. How many lights was that in total? *Bonus: *Potts then built one with 3 colors on each of 4 sides. How many lights did that have?

*Big kids:* Most lights stay on red for only about 15 seconds, but some lights take forever. If the traffic light for your direction signal spends 15 seconds on green, 5 seconds on yellow, and 40 seconds on red, how long is a full cycle of green to yellow to red? *Bonus:* If 8 cars can get through the green each time, how many cars make it through the light in 5 minutes?

Answers:

*Wee ones:* 4 lights.

*Little kids:* 8 lights in total. *Bonus:* 12 lights in total.

*Big kids:* 60 seconds, or 1 minute. *Bonus:* 40 cars.

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]]>The post The Tastiest “Type” of Waffles appeared first on Bedtime Math.

]]>Fluffy waffles taste great in any shape: a square, a circle, a rectangle, or really any shape that has those square holes to catch the syrup. Well, the best shape of all may be a waffle shaped like your computer. Someone invented a waffle iron that stamps out waffles with little pockets shaped just like the keys on a keyboard: 4 rows of squares for the letters and numbers, rectangles for Backspace and Enter, and a really long skinny pocket for the space bar. Computer keys are squares and rectangles, so it works out perfectly!

*Wee ones:* How many sides does a square have?

*Little kids:* If there are 3 big keys at the left end, 4 on the right end, and the big space bar along the bottom, how many big syrup-y keys are there? *Bonus:* If you drizzle syrup on every other key in the top row starting with the 1st key, how many of those 14 keys will catch syrup?

*Big kids:* If the 4 rows of keys have 12, 11, 11 and 10 square keys respectively, how many keys does that give you? *Bonus:* If those cover the 26 letter keys and 10 digit keys (1, 2, 3, etc.), how many other keys does the board have?

*The sky’s the limit:* The inventors needed $50,000 to build a factory to make these waffle irons. If they spent the first $8,000 to build the factory machines, and it then costs $200 to make each waffle iron, how many irons can they make with the money raised?

Answers:

*Wee ones:* 4 sides.

*Little kids:* 8 keys. *Bonus:* 7 keys.

*Big kids:* 44 keys. *Bonus:* 8 keys, since 36 are covered by letters and numbers.

*The sky’s the limit:* They’ll have $42,000 left to make the irons, so they can make 210 irons.

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