Celebrating Square Root Day

Square Root Day is when the month and the day are the square root of the year. It only happens nine times in a century, and today (3-3-09) is one of those days.

The holiday is the brainchild of Sequoia High (Redwood City, California) driver education teacher Ron Gordon, who enjoys calendar quirks. He's tried to get schools to celebrate Square Root Day since 1981. Gordon also inspired a celebration of Odd Day on March 5, 2007 (3-5-7). He is giving away a prize of $339 to the person who has the best Square Root Day celebratory event. What can you do to celebrate Square Root Day? Math teachers expect students to calculate square roots. We should do something fun in addition.


Robert X. Cringely at Infoworld has a plan for celebrating Square Root Day.

I don't know about you, but I'm planning to celebrate by watching a "SpongeBob SquarePants" marathon while playing with my slide rule.

That's only the beginning of the many ways you can celebrate Square Root Day.


The established custom is to cut root vegetables (carrots, turnips, radishes) into squares. Actually eating them may be asking too much. But potatoes are roots, aren't they? Square (or cubic) potatoes can mean only one thing -home fries.


For dessert you need to make a carrot cake. Square, of course. There are plenty of different recipes, all you have to do is find one that fits the ingredients you have. Enjoy it with some root beer. Oh yes, I'll have a slice, thank you very much!


Buy yourself a square root puzzle. You won't receive it in time to play today, but you'll be ready for the next holiday in 2016.


You can play Square Root Clock online. There are plenty of online games that challenge your math skills using square roots, but this is the most photogenic.

Then there's always a little square root poetry. This example is from Harold and Kumar Escape from Guantanamo Bay (contains spoiler, if you care).


After all the food and math, grab seven of your friends and have a square dance. Some basic instructions are at Square Dancing 101. Allemande left, 2 by 2! Image by Wikimedia user Deirdre.


If you are so inclined, you might go looking for a real square root in the world around you. They are kind of rare. Image by Flickr user arsheffield.


And if that's not enough fun for you, we're only a couple of weeks away from Pi Day! But celebrate Square Root Day wisely. The next such holiday will be on April 4, 2016.

Honey Bees Can Understand the Concept of Zero

The concept of zero—less than one, nothing, nada—is deceptively complex. The first placeholder zero dates back to around 300 BCE, and the notion didn’t make its way to Western Europe until the 12th century. It takes children until preschool to wrap their brains around the concept. But scientists in Australia recently discovered a new animal capable of understanding zero: the honey bee. According to Vox, a new study finds that the insects can be taught the concept of nothing.

A few other animals can understand zero, according to current research. Dolphins, parrots, and monkeys can all understand the difference between something and nothing, but honey bees are the first insects proven to be able to do it.

The new study, published in the journal Science, finds that honey bees can rank quantities based on “greater than” and “less than,” and can understand that nothing is less than one.

Left: A photo of a bee choosing between images with black dots on them. Right: an illustration of a bee choosing the image with fewer dots
© Scarlett Howard & Aurore Avarguès-Weber

The researchers trained bees to identify images in the lab that showed the fewest number of elements (in this case, dots). If they chose the image with the fewest circles from a set, they received sweetened water, whereas if they chose another image, they received bitter quinine.

Once the insects got that concept down, the researchers introduced another challenge: The bees had to choose between a blank image and one with dots on it. More than 60 percent of the time, the insects were successfully able to extrapolate that if they needed to choose the fewest dots between an image with a few dots and an image with no dots at all, no dots was the correct answer. They could grasp the concept that nothing can still be a numerical quantity.

It’s not entirely surprising that bees are capable of such feats of intelligence. We already know that they can count, teach each other skills, communicate via the “waggle dance,” and think abstractly. This is just more evidence that bees are strikingly intelligent creatures, despite the fact that their insect brains look nothing like our own.

Considering how far apart bees and primates are on the evolutionary tree, and how different their brains are from ours—they have fewer than 1 million neurons, while we have about 86 billion—this finding raises a lot of new questions about the neural basis of understanding numbers, and will no doubt lead to further research on how the brain processes concepts like zero.

[h/t Vox]

Can You Solve This Ice Cream Cone Riddle?

How much is an ice cream cone worth? In this visual riddle by Budapest-based artist Gergely Dudás (who posts comics on Dudolf.com), the answer requires a little math.

The riddle asks you to determine how much an ice cream cone, a scoop of white-colored ice cream (let’s call it vanilla), and a scoop of pink-colored ice cream (let’s call it strawberry) are worth, according to the logic of the puzzle.

Stare at the equations for a while, then scroll down for the answer.

A math riddle that asks you to figure out what numbers each ice cream cone or scoop represents
Gergely Dudás


Are you sure?

OK, let's walk through this.

Three ice cream cones multiplied together are equal to the number 27. Since 3 multiplied by 3 multiplied by 3 equals 27, each cone must be equal to 3.

Moving on to the next row, two ice cream cones each topped with a scoop of vanilla ice cream added together equal 10. So since each cone equals 3, the vanilla scoops must each equal 2. (In other words, 3 plus 3 plus 2 plus 2 equals 10.)

Now, a double scoop of vanilla on a cone plus a single scoop of strawberry on a cone equals 11. So if a double-scoop of vanilla equals 4 (2 plus 2) and each cone is equal to 3, the strawberry scoop must equal 1. (Because 4 plus 6 equals 10, plus 1 for the strawberry scoop equals 11.)

And finally, one vanilla scoop on a cone, plus one empty cone, plus a double-scoop of strawberry and a single scoop of vanilla on a cone, all together equals 15. One scoop of vanilla on a cone is equal to 5 (2 plus 3), and an empty cone is equal to 3. Two strawberry scoops plus one vanilla scoop plus one cone can be calculated as 1 plus 1 plus 2 plus 3 (which comes out to 7). So together, one vanilla scoop (5) plus one cone (3) plus a triple scoop with two strawberries and one vanilla on a cone (7) equals 15.

And there you have it.

A cartoon-style legend that shows that one cone equals 3, one white scoop equals 2, and one pink scoop equals 1.
Gergely Dudás

If frozen dairy-themed challenges are your thing, he also has a hidden image puzzle that challenges you to find the lollipop in a field of ice cream cones. Check out more of his work on his website and Facebook.


More from mental floss studios