The post Can You Drink a Whole Lake? appeared first on Bedtime Math.

]]>We got an awesome question from Bedtime Math fan Carmel P.: could you drink a whole lake in an hour? Well, you’d better hope it’s a small lake! Look at a 1/2 gallon of milk: that’s already a lot to drink. Now imagine a 1-foot wide cube…it would hold 8 gallons, or 16 cartons. Now imagine a 20- by 20-foot square swimming pool that’s 10 feet deep: it holds 20 x 20 x 10 = 4,000 cubic feet of water, or 64,000 milk cartons! NOW imagine a square-ish lake 200 feet wide and long and 100 feet deep. That holds 10 pools across, 10 pools from back to front, and 10 layers of pools top to bottom…you’d have to drink 1,000 swimming pools in an hour, or about 1 every 3 seconds. You’ll need a pretty fat straw for that!

*Wee ones:* If you could drink 5 whole swimming pools, what numbers do you say to count them?

*Little kids:* If a “little” lake holds 9 pools of water and you’ve drunk 5 pools of water, how many pools of water do you have left to drink? Count up to find out! *Bonus:* If you make it to only halfway between 5 and 9, how many swimming pools do you drink in total?

*Big kids:* If a lake holds “just” 8 million gallons, how many people can drink it down if each person drinks just 1/4 gallon? (*Hint if needed:* That means it takes 4 people to drink each gallon.) *Bonus:* If you could drink 10 whole swimming pools every 10 minutes, could you empty a 100-pool lake in 1 hour?

*The sky’s the limit:* Lake Superior in the U.S. holds 3 *quadrillion* gallons of water! Can you “spell” 3 quadrillion in digits? Hint: A quadrillion is one thousand trillions, and a trillion is one thousand billions.

Answers:

*Wee ones:* 1, 2, 3, 4, 5.

*Little kids:* 4 more pools’ worth of water. *Bonus:* 7 pools.

*Big kids:* 32 million people, because each gallon needs 4 people tackling it. That’s almost all the people in Canada. *Bonus:* No: there are only 6 10-minute chunks in an hour, so you could drink only 60 pools in an hour. Another way to think of it: 10 pools in 10 minutes is 1 pool per minute, so that’s 60 in an hour.

*The sky’s the limit:* 3,000,000,000,000,000 gallons!

The post Can You Drink a Whole Lake? appeared first on Bedtime Math.

]]>The post Spotlight on 11/11 11:11 appeared first on Bedtime Math.

]]>We love the geometry — the math behind shapes — in this amazing sculpture. At the Anthem Veterans Memorial in Arizona, the sun is part of the show every Veterans Day. Every year on 11/11, at exactly 11:11 in the morning, the sun lines up perfectly to shine through the 5 ovals, and lights up the United States Seal on the ground. With Earth traveling around the Sun, and spinning all day and night on a tilt, this sculpture lines up only at this moment of the year — plus one moment in the spring, because Earth hits the same tilt somewhere on the other side of the Sun. Each rectangle stands for a branch of the U.S. military: Army, Marines, Navy, Air Force, and Coast Guard. As America honors our veterans today, the sun can celebrate with us.

*Wee ones:* The holes in the pillars are “ellipses,” or ovals. How are ovals different from circles? Discuss!

*Little kids:* If the moment happens at about 11 am and you show up 3 hours early, at what time do you get there? *Bonus:* The shortest rectangle pillar stands 6 feet tall. If each pillar were exactly 3 feet taller than the one before it, how tall would the next two pillars be?

*Big kids:* If the heights of the pillars are all evenly spaced from each other between 6 and 17 feet, how tall is the middle pillar? *Bonus:* If the other day of the year that this happens is as many days before the start of fall (Sept. 23) as this day is *after* Sept. 23, on what other day does this sun show work? (*Reminder if needed:* 30 days hath September, April, June, and November…all the rest have 31, except February which has 28.)

Answers:

*Wee ones:* They’re both round, but circles are the same width in every direction, while ellipses are longer across one direction and shorter across another.

*Little kids:* At 8 am. *Bonus:* 9 feet and 12 feet.

*Big kids:* 11 1/2 feet. *Bonus:* On August 5. November 11 is 7+31+11 days after Sept 23, or 49 days. So we now need to find the date 49 days *before* Sept. 23. September 1 is 22 days before, so August 31 is 23 days before it…we need to back up another 26 days from that, bringing us to August 5.

The post Spotlight on 11/11 11:11 appeared first on Bedtime Math.

]]>The post A Berry Big Mess appeared first on Bedtime Math.

]]>The farmers in this picture look like goofballs standing in that water. Well, that’s actually how cranberries are harvested. Cranberry vines grow in very wet fields called bogs. Most of the time the ground is just really squishy and soggy, but in late fall when it’s time to harvest the berries, the farmers flood the bogs with water. As the cranberries fall off the branches, they just float around until they’re corralled for collection. Interestingly, cranberries sold fresh have to be “dry-picked” from the vines. But any time you enjoy cranberries as juice, cranberry sauce, or dried or frozen, you know that those berries all went for a swim on their way to your table.

*Wee ones:* If you have 8 berries in your left hand and 9 in your right hand, which one is holding *fewer*?

*Little kids:* If you eat 5 fresh, very sour cranberries and 5 yummier dried ones, how many berries do you eat in total? *Bonus:* If the cranberry vines are 24 inches tall and the farm floods the bog to 6 inches above that, how deep will the water be?

*Big kids:* If you stood in 2-foot-deep water to help harvest berries, how much of your body would stick out above the water? (Reminder: One foot has 12 inches.) *Bonus:* If a farm runs 7 bogs and each bog has 6 million cranberries floating around, how many millions of berries will they harvest?

*The sky’s the limit:* Packagers buy cranberries by the barrel, which holds 100 pounds of berries. If someone sells you 3 barrels and you eat 1/2 the berries yourself, then your friend eats 1/3 of what *you* left…what fraction of the starting amount is left in the end?

Answers:

*Wee ones:* Your left hand has fewer.

*Little kids:* 10 cranberries. *Bonus:* 30 inches.

*Big kids:* Different for everyone: subtract 24 from your height in inches. *Bonus:* 42 million cranberries.

*The sky’s the limit:* 1/3 of the original 300 pounds. If you eat 1/2, that leaves 150 pounds; if your friend eats 1/3 of *that*, that’s 50 more pounds taken away, leaving 100 pounds.

The post A Berry Big Mess appeared first on Bedtime Math.

]]>The post Pocket-Sized Pooches appeared first on Bedtime Math.

]]>Dogs make great pets: it’s so nice to snuggle that big, furry bundle. But it’s hard to hug a dog who’s as small as your hand! The world’s smallest dog by length is a Chihuahua named Heaven Sent Brandy. She’s only 6 inches long even though she’s fully grown. Then there’s the world’s smallest dog by height, Milly. She’s a Chihuahua too, and is only 3.8 inches tall. She weighs only 1 pound. Just to compare, the longest tongue on a dog is over 7 inches long, belonging to a St. Bernard named Mochi. Maybe Milly and Brandy want to stay out of his way!

*Wee ones:* If Heaven Sent Brandy is 6 inches long and Milly is 1 inch longer, how long is Milly?

*Little kids:* How many legs do Heaven Sent Brandy and Milly have together? *Bonus:* Which weighs more, Milly at 16 ounces, or 4 iphones at 5 ounces each? Count up by 5s!

*Big kids:* Milly was born in 2011, while Heaven Sent Brandy was born 8 years earlier. How old was Heaven Sent Brandy when she set the world record in 2005? *Bonus:* If Mochi’s tongue is 7 1/4 inches long and Milly is just 6 inches, how much longer is Mochi’s tongue?

Answers:

*Wee ones:* 7 inches.

*Little kids:* 8 legs. *Bonus:* The 4 iPhones are heavier, at 20 ounces.

*Big kids:* 2 years old, since she was born in 2003. *Bonus:* 1 1/4 inches longer.

The post Pocket-Sized Pooches appeared first on Bedtime Math.

]]>The post Putting the Jelly in Jellyfish appeared first on Bedtime Math.

]]>We have jelly, and we have fish…and then we have jellyfish. Jellyfish can be smaller than your fingernail, or up to 6 feet wide! They can weigh as much as 440 pounds, but not all of them are dangerous. Even so, our fan Adrian N. just had to ask, how many jellyfish are there in the world? (and drew this great picture, too!) Turns out it’s hard to swim around counting these things. Scientists say jellyfish make up 40% of the weight of all living things in the ocean, which comes to about 3.4 billion tons, or almost 7 trillion pounds of goopy jellyfish. If jellyfish weigh 4.4 pounds on average, that gives us between 1 to 2 trillion jellyfish. Too bad they can’t be part of our PB&J sandwiches.

*Wee ones:* Some jellyfish are flat circles. Find 3 circle shapes in your room.

*Little kids:* Which weighs LESS, a 5-pound jellyfish or an 9-pound jellyfish? *Bonus:* How much would a jellyfish weigh if it were halfway between those two?

*Big kids:* If you go fishing and pull in a thousand 6-pound jellyfish, how many tons do they weigh? (*Reminder if needed:* A ton equals 2,000 pounds.) *Bonus:* A lion’s mane jellyfish’s tentacles (squiggly legs) can be 120 feet long! If your house is a perfect square, with same length as width, how wide could it be for the jellyfish still to be able to wrap around once?

Answers:

*Wee ones:* Things might include plates, the rims of cups, and the faces of clocks and watches.

*Little kids:* The 5-pound jellyfish weighs less. *Bonus:* 7 pounds.

*Big kids:* 3 tons, since they weigh 6,000 pounds. *Bonus:* 30 feet wide (120 split into 4 equal parts for the 4 sides).

The post Putting the Jelly in Jellyfish appeared first on Bedtime Math.

]]>The post Counting the Stars appeared first on Bedtime Math.

]]>Have you ever tried to count the stars in the sky? There are so many! But we know all those stars and have given them names. Once in a while, though, even a kid can find a new star. On this day in 2008, 14-year-old Caroline Moore studied photos from her telescope and found an exploding star — called a supernova — that no one had ever spotted before. Then on December 31, 2010, a 10-year old named Kathryn Gray found another one, beating the record for youngest supernova discoverer ever. There are far more stars to find, so grab your telescope!

*Wee ones:* Once it’s dark out tonight, can you see any stars, or the Moon or any bright spots? Count as many as you can!

*Little kids:* If in the hazy night sky you can see the moon, 4 stars, and the planets Venus and Jupiter, how many night sky objects can you see? *Bonus:* If you count up 70 stars in batches of 10, what numbers do you say to count them off?

*Big kids:* If in one square section of the sky you count 12 stars, then look at it through a telescope and see 4 times as many stars, how many do you see now? (Quick trick: to multiply by 4, you can double the number, then double it again.) *Bonus:* If you divide the sky into 20 equal sections, and you count 100 stars in one chunk, how many stars can you guess are showing across the whole sky?

Answers:

*Wee ones:* 1, 2, 3, 4, and so on…into the hundreds if you’re not tired!

*Little kids:* 7 night objects. *Bonus:* 10, 20, 30, 40, 50, 60, 70.

*Big kids:* 48 stars. *Bonus:* 2,000 stars — about how many the naked eye can see on a clear dark night.

The post Counting the Stars appeared first on Bedtime Math.

]]>The post How to Get a Bigger Brownie appeared first on Bedtime Math.

]]>Normally you cut a tray of brownies with straight lines to make squares or rectangles. If the pieces come out uneven, you hope you get the biggest one. But this cake-cutter by Matthias Wandel makes hexagons instead! Check out those cool chocolate-chip bars. There are *only* 3 shapes with all equal sides and angles that can fit together with no gaps or overlaps: hexagons, squares…and can you think of the last one? Triangles. Try cutting your brownies that way, too!

*Wee ones:* How many sides does a hexagon have? Check out the picture!

*Little kids:* If you eat a hexagon brownie and then a normal square one, how many edges do they have all together? *Bonus:* If you cut 2 straight lines across a square cake and then 2 straight lines from back to front, how many pieces will you have?

*Big kids:* If you cut your brownies into 6 rows of 4 hexagons plus 6 half-hexagons, how many total hexagons do you have? *Bonus:* If you can fit 36 squares instead, how many more brownies do you have by cutting squares?

*The sky’s the limit:* By what *fraction* is each of 27 hexagons bigger than one of the 36 squares from the same size tray?

Answers:

*Wee ones:* 6 sides.

*Little kids:* 10 edges, since the square has 4. *Bonus:* 9 pieces — imagine a tic tac toe board.

*Big kids:* 27 hexagons, since the 6 halves give you 3 more. *Bonus:* 9 more brownies.

*The sky’s the limit:* 1/3 bigger than a square. Each hexagon is 4/3 of a brownie, since you can cut only 3/4 as many of them. If you carve out 3/3 for the square brownie, you’re left with 1/3 extra.

The post How to Get a Bigger Brownie appeared first on Bedtime Math.

]]>The post Can a Bird Take You for a Ride? appeared first on Bedtime Math.

]]>We got a great question from our longtime fan Kaien M.: How many birds would it take to pick you up and fly with you? Well, it depends on how much you weigh, and how much each bird can carry. Birds come in all sizes, and some have stronger wings than others. A tiny swallow can probably carry only about 1 ounce. If you weigh 60 pounds, you’d need 960 swallows to pick you up! On the other hand, the harpy eagle can carry 20 pounds. So you’d need only 3 eagles to pick up a 60-pound kid. If you want to fly, too, do the math to find out how many pet birds you’ll need!

*Wee ones:* If 8 hawks pick you up, what numbers would you say to count them?

*Little kids:* If 3 harpy eagles pick you up and fly you around, how many wings do they have as a group? *Bonus:* How many more legs than wings in the group? (Don’t forget to count yourself!)

*Big kids:* If an eagle can lift 20 pounds, at least how many eagles does it take to pick you up? (It doesn’t need to work out exactly — just make sure they can carry you!) *Bonus:* How many little sparrows could pick you up if each sparrow can carry 1 ounce? (Reminder: A pound has 16 ounces.)

*The sky’s the limit — literally:* If it takes either 20 geese to pick you up or 30 ducks, how many geese does it take to pick up a person that 120 ducks can lift?

Answers:

*Wee ones:* 1 ,2, 3, 4, 5, 6, 7, 8.

*Little kids:* 6 wings. *Bonus:* 2 more legs than wings. You can either subtract 6 from 8, or just remember that you add 2 legs but no wings to the group.

*Big kids:* Different for everyone…find the closest multiple of 20 just above your weight in pounds, then divide by 20. *Bonus:* Also different for you all…take your weight in pounds and multiply by 16, which gives you the total ounces and also the total number of sparrows.

*The sky’s the limit:* 80 geese. Every 30 ducks match 20 geese, and 120 ducks have 4 of those sets of 30. So you need 4 sets of 20 geese, or 80 geese.

And thank you Kaien for getting us all to take flight with math. If others of you out there have a question you’d like us to answer, send it in and we’ll give it a try!

The post Can a Bird Take You for a Ride? appeared first on Bedtime Math.

]]>The post Carpool, or Pool Car? appeared first on Bedtime Math.

]]>Pools and bathtubs are a great place to play and to relax. But have you ever gone swimming in one while it’s rolling down the road? Duncan Forster and Phil Weicker tried it: they turned an old car into a hot tub. They took apart a 1969 Cadillac, added steel bars across the bottom to hold all the extra water weight, and then built a hot tub that fit perfectly inside the car. They filled it with water, and as you see here, they can drive it like that! They’ve nicknamed the car “Carpool Deville” and hope to set the world land speed record for the fastest-moving tub, because believe it or not, no one has tried this stunt yet.

*Wee ones:* If your car had a tub in it, how many tubs would your home and car have together?

*Little kids:* If you’re adding 400 gallons of water to the pool car, how would you count that up by 100s? *Bonus:* If the car holds 2 people and 7 more rubber duckies than people, how many riders are there?

*Big kids:* If the highway speed limit is 60 miles per hour and the guys drive their tub just 1 mile per hour more slowly than that, how fast a record do they set? *Bonus:* The two men raised $10,000 for their project, and bought the old car for $800 on eBay. How much money did that leave them to rebuild the car? (*Hint if needed:* What would they have left if they’d bought the car for $1,000?)

Answers:

*Wee ones:* Different for everyone…figure out how many tubs you have in your house, and add 1!

*Little kids:* 100, 200, 300, 400. *Bonus:* 11 riders, since there are 9 (7+2) rubber duckies.

*Big kids:* 59 miles per hour. *Bonus:* $9,200.

The post Carpool, or Pool Car? appeared first on Bedtime Math.

]]>The post Lost and Found, Forever appeared first on Bedtime Math.

]]>Have you ever found something that you lost so long ago you forgot all about it? Imagine Derek Gamble, who lost his wallet on a train…30 years later, train driver Michael Massey found it wedged inside the seats and mailed it to him! Then there’s Ed Grigor, whose watch was stolen from him, then found and sent to him 53 years later. The wildest lost and found, though, might be the Stanford University weather balloon carrying a GoPro camera, so it could photograph the Grand Canyon from miles above. When the camera fell back to Earth, the students couldn’t find it. But an Arizona hiker found the camera 2 years later, full of amazing pictures of Earth from space. Well worth the wait!

*Wee ones:* If that long-lost wallet had 6 really old coins, what numbers would you say to count them?

*Little kids:* If your favorite Lego piece gets vacuumed up in March and pops out 3 months later, in what month do you get it back? *Bonus:* If the space camera was launched in 2013 and found 2 years later, in what year was it found?

*Big kids:* If you’ve been searching for your favorite sneakers since October 17 and you find them tonight, how many days after losing them did you find them? (Reminder: October has 31 days, and today is November 3.) *Bonus:* If the camera flew 5 miles up and then fell 5 miles down, how many feet did it travel? (Hint if needed: A mile has 5,280 feet.)

*The sky’s the limit:* If you lost your sneakers 10 months ago and found them 4 months later, and you lost your favorite shirt 2 years ago and found it halfway between losing and finding your sneakers, how long were you missing the shirt?

Answers:

*Wee ones:* 1, 2, 3, 4, 5, 6.

*Little kids:* In June. *Bonus:* In 2015.

*Big kids:* 17 days, since Oct. 31 takes you to 14 days. *Bonus:* 52,800 feet, since it traveled 10 miles in total.

*The sky’s the limit:* 16 months. You lost your sneakers 10 months ago and found them 6 months ago (4 months later), making the halfway point 8 months. Your shirt went missing 24 months ago, so from that time to 8 months ago is 16 months.

The post Lost and Found, Forever appeared first on Bedtime Math.

]]>