Stories tagged math

It's almost commonplace these days to discover hidden talents in animals, but...plants doing math?

Yep.

All together now

by mdr on May. 15th, 2013

What happens if you start 32 metronomes at different times on a stable surface? Not much. They'll tick-tock out of sync until the cows come home. But what happens when you start the same 32 metronomes on an unfixed surface? You get to witness a nifty (and mesmerizing) example of coupled oscillations. Watch and learn.

Pick a number: The PIN you punch in at an ATM can have a higher or lower level of security based on the order of the numbers you pick.
Pick a number: The PIN you punch in at an ATM can have a higher or lower level of security based on the order of the numbers you pick.Courtesy Victor van Werkhooven
What are the most popular PIN numbers people use? What are the least? How can you best ensure that your PIN is something crooks would have a lesser chance of figuring out? This is a pretty neat report that talks about what works, and what doesn't, when selecting a personal identification number to use with some financial or electronic devices. You'd be surprised how often people commonly make mistakes that lead to easy uncovering of their PINs.

Vi Hart and Khan Academy, both amazing online resources for mathematical inspiration and intuition, have decided to combine their efforts. Here is their official announcement:

See video

Jan
07
2011

It's a big drawer: But I'm a grown man. This could be close...
It's a big drawer: But I'm a grown man. This could be close...Courtesy JGordon
The human body is more or less the density of water: 1000 kg per cubic meter. (I tend to sink, so I'm probably a little denser, but I think we're close enough here.)

I weigh about 150 pounds, or 68 kg (2.2 pounds per kilogram).
1000kg / 1m^3 = 68kg / ?m^3
? = .068
So the volume of my body is about 0.068 cubic meters.

Each cubic meter equals about 35.3146667 cubic feet.
.068 x 35.315 = 2.401
So the volume of my body is about 2.401 cubic feet

My file drawer is 1 foot wide by 9 inches high (or .75 feet) by 2 feet and 2 inches deep (or 2.167 feet)
1 x .75 x 2.167 = 1.62525
So the volume of my desk drawer is 1.62525 cubic feet

1.62525 < 2.401
So the answer is NO. If you were to blend me up in a giant food processor, and then pour me into my file drawer, I would literally be overflowing.

That's sort of a relief.

Then again, it depends on how much denser I am than water. Maybe I would fit.

101010: 101010 = 42.
101010: 101010 = 42.Courtesy jimmowatt
"101010 (base two (binary)) equals 42 (base ten). Oddly enough, this is evenly divisible by the number of days in a week (7 (lucky)); and equally oddly, is also evenly divisible by the number 6 (which is generally designated as being unlucky). Both a Ying and Yang situation seem to be incorporated into this date." HubPages.com

10 (base ten) = 1010 (base two)

(base ten): 10 x 10 = 100

(base two): 10 x 10 = 100

42 is the answer to everything

In Hitchhiker's Guide to the Galaxy, the
"Answer to Life, the Universe, and Everything" was 42.
Fortytwoday.com
.

May
07
2010

One man, one vote.: But how those votes are counted can lead to some surprisingly complex mathematics.
One man, one vote.: But how those votes are counted can lead to some surprisingly complex mathematics.Courtesy Theresa Thompson

Winston Churchill once quipped, "democracy is the worst form of government, except for all the others." Though said tongue-in-cheek, a recent article in New Scientist shows that, mathematically at least, Winnie was on to something.

Every election has winners and losers. Different countries have different systems for determining the winners, and dealing with the losers. And, it turns out, each of those systems has mathematical quirks which prevent the results from perfectly matching the will of the people.

  • The "winner-take-all" system used in America is certainly very simple and straight-forward. The problem is, the thousands--or even millions--of people who voted for the losing candidate end up with no elected official representing their views. (In the recent British elections, the Liberal Democratic party won 23% of all individual votes cast, but ended up with less than 9% of the seats in Parliament.) And in a race with three or more candidates, you can get a winner who carries less than 50% of the vote.
  • Some countries get around this by using "proportional representation:" they count votes cast for each political party, rather than for individual candidates, and divvy up the legislature that way. The voters' voice is fairly represented. But if one party controls more than half the seats, it can effectively shut the minor parties out. And if no party has a majority, they end up sharing power in ways that do not reflect their numbers. (Again, the British elections are a good example. The leading Conservative Party won 37% of the vote and 47% of the seats--not quite enough for a majority. They may form an alliance with the Liberal Democrats. The two parties would share power 50%-50%--quite a boon for the LibDems, who control only 9% of the seats!)
  • A few countries have tried "ordered voting," in which voters rank all candidates in order of preference, and then conducting run-offs until someone gets 50% of the vote. But this can lead to a strange situation where nobody wins!
  • And dividing the electorate into districts can shift power in unexpected ways. (We had a Buzz exhibit last year explaining how the Electoral College redistributes power.)

In 1963, American economist Kenneth Arrow considered all these quirks and tried to describe the perfect voting system. He then proved that it was mathematically impossible. (Of course, this assumes the system he described really is perfect--I'm not so sure.)

It seems to me, though, that the problem isn't with democracy, but rather with representative democracy. The people of Minnesota elect only one governor, only one senator (at a time). And there's no way one person is going to perfectly reflect public opinion--be 53% in favor of issue A and 61% opposed to issue B. And even if they were, they still have to make a series of yes-or-no decisions, and be either 100% for 100% against any given bill.

The only way to have a perfect democracy is to have everybody vote on every issue, a system that would be far too cumbersome to work. Churchill was right: democracy is messy, but it's the best thing we've got.

Two girls tackle their math together: Are they inadvertently taught to fear it?
Two girls tackle their math together: Are they inadvertently taught to fear it?Courtesy gr8matt
Researchers at the University fo Chicago have published a new report in PNAS that shows math anxiety in elementary school teachers (which are predominantly female) is passed on to the young girls in their classes. The research is reported on the Smithsonian's Surprising Science blog site.

http://blogs.smithsonianmag.com/science/2010/01/26/elementary-school-tea...

Pi are squared; cake are round: Photo courtesy LeJyBy at Flickr Creative Commons
Pi are squared; cake are round: Photo courtesy LeJyBy at Flickr Creative Commons
Using a desktop computer, a scientist says he's calculated pi to almost 2.7 trillion digits! That's enough information to fill more than a thousand gigabytes (one terrabyte) of hard drive space, and would take more than 49,000 years of around-the-clock counting to count at one number per second. Could this mean more slices for everyone? Let's hope so.

SOURCE
BBC report