Even though I only started keeping track of timed quizzes back in March, the list already contains over 230 quizzes at this writing!

As you can see from the Mental Gym page, I've even been working on my own timed quizzes. I've updated the already-existing quizzes so that the clock doesn't start counting down until you start typing. Being based on Javascript, I've also received numerous comments about the ease of simply selecting the option to view the page source to see the answers. In response to this, I've obfuscated the answers within the code itself, so that this method can no longer be used.

In the past few days, I've also added two new timed quizzes. The first concerns the 12 current US Monopoly playing pieces.

The other one is about the impossible contest songs from a classic episode of WKRP In Cincinnati called The Contest Nobody Could Win (full episode). The version of the song I used for the quiz was recorded from the original airing of the episode. For the online Hulu broadcast, as well as the DVD release, the songs (as well as the voices doing the guessing) have been re-dubbed due to royalty issues, so referring to those won't be of much help.

While I'm on the topic of timed quizzes, there are a few that I've wanted to include on the list, but for one reason or another, never really seemed to fit. A good example would be this US states quiz, which didn't fit because it's made for printing out, instead of my focus on playable online timed quizzes.

Even when they're playable online, they don't always fit my other criterion that you must type the answers in, as opposed to just pointing, or dragging and dropping answers. There are some excellent quizzes of this type, including Map Test, and the quizzes from Web Anatomy (which can be timed or not, as you prefer).

My personal favorite of these, though, would have to be Traveler IQ, which can quiz you on all levels of geography, from flags and cities, all the way up to the entire world! They've even added badges you can post on your site.

I hope you enjoy these. As always, if you know of any timed quizzes I've missed, or have any suggestions for the ones on my site, please leave me a note in the comments.

With the long awaited 3G iPhone rumored to be released on June 9th, this is probably a good time to update the iPhone/iPod Touch Mental Gym.

Thanks to the creativity of the team at 38i, I've added three new challenging puzzles for you to master.

The first is called Flip-It, where you have to put the numbered tiles in order from 0-9, but you're always flipping 6 pieces at a time. You can find information, and even solving procedures, at Jaap's Flip-Side page. Flip-Side is the name for the marketed version of this puzzle.

The second new addition is Rubik's Rings. In this one, you have two intertwining circular tracks which are filled with marbles of three different colors: red, blue, and yellow. The object is to get all the red marbles on one outer track, all the blue marbles in the other outer track, and all the yellow marbles in the inner tracks. Since there are no gaps, every marble you move results in the entire ring moving, which is what makes this puzzle so tough. Yes, this was also an actual marketed product. After getting frustrated with this puzzle, you can learn how to solve it at Jaap's Rubik's Rings / Hungarian Rings page. Hungarian Rings adds another color, so when reading, make sure you're following the solution for Rubik's Rings, not the Hungarian ones.

The last of the new puzzles is UriBlock. At first, this looks like the classic 15 puzzle that should be easier to solve, due to the pieces being only 4 different colors, instead of 15. Beware though, because there are 16 pieces, not 15, and there are no gaps. Even the simplest move will change the location of 3 different pieces in various rows and columns. The greater difficulty, compared to that of the 15 puzzle, quickly becomes apparent. Yes, Jaap comes to the rescue again with his UriBlock page.

Go ahead and try out both the new and old games in the iPhone/iPod Touch Mental Gym, and try to master them. You don't even have to own an iPhone or an iPod Touch to play them! I've made sure that all of these games area accessible and function on a regular computer. Enjoy!

There was a time when anyone you met on the street could name all the elements from memory. Of course, that was also when there were only four elements: Fire, Air, Earth, Water. The modern chemical elements are more numerous, but they can still be memorized.

Before we get into the elements themselves, however, we need to start with something more basic. What is it with the periodic table and that weird shape?!? Fortunately, Chem4Kids provides an excellent basic introduction to the periodic table here. If you're curious all about chemistry basics, or just forgotten about what you learned in school, there's a great and simple multi-page tour on the site, too. Memorizing is good, but memorizing along with understanding is always more effective.

The two standard ways that have been used to memorize the chemical elements. Obviously, you could use standard memory techniques, and customize them as described in the periodic table section of the Memory Page. A more detailed version of this approach can be found on this archived copy of SoundNumbers.com's Periodic Table page . This latter page includes mnemonics for the elements as an ordered list, by number, and even each elements' atomic weight!

Another classic way to learn the elements has been to memorize Tom Lehrer's The Elements Song (Flash required). Even though it was written in 1959, the video is helpful and lists elements discovered after that time.

However, there have been improvements in learning the elements since these approaches were first used. The same people who brought you the 50 States of Mind website I mentioned in my previous post have also developed a mnemonic version of the periodic table they call The Atom Families. On their Big Table, they replace the standard symbols with pictures for every element for which they've developed a pictorial mnemonic. On their Iron page, for example, they've got an iron robot (Rosie from The Jetsons) who is ironing, and it is mentioned you should picture her as being made of Ferris Wheel parts, to help you remember the Fe symbol (iron, in Latin, is ferrum).

Unfortunately, the previous table is incomplete, and will only help you remember the elements and their symbols. Fortunately, there's been a complete mnemonic periodic table on the web since 1997 (keep in mind that the site design is also from 1997)! John Pratt's Periodic Table Memory Pegs are complete, and each mnemonic will help you remember the element's name, its chemical symbol, and its number on the table! You can click on an individual picture in the table to go straight its description and explanation, or you can learn the mnemonics 20 at a time by stepping through the pages (this is an excellent way to break it down when you're just learning it!). If you do get this version down and want to add the atomic weights, it wouldn't be tough (with a little imagination) to use the atomic weight mnemonics from SoundNumbers.com.

What's the use of memorizing the elements if you're never going to use them? You can simultaneously use and practice them by quizzing yourself! In my How Many Xs Can You Name In Y Minutes? post, there are (at this writing) two timed quizzes focusing on the elements (in the Science section), one at Kongregate, and the other at Sporcle. There's also a third quiz, if you count Mental Floss' Noble Gases quiz.

Speaking of fun with the elements, here's a page featuring the age-old game of spelling words with just the elemental symbols. You can challenge your friends to do things like create the longest word they can with this limitation (Can you beat helicopters?). Of course, if you get tired of trying to figure out whether a particular word can be made this way, you can cheat like heck using this periodic search engine. Using that search engine, here's how my earlier helicopters example breaks down into elemental symbols.

It was a little over a year ago that I last focused on the states, so it's time to visit them again (so to speak).

During a recent speech in Oregon, US Presidential candidate Barack Obama recently made a newsworthy mistake when stating that there were 60 states total (57 visited states + 1 unvisited state + 2 states, Alaska and Hawaii, that won't be visited):

Also, when asked why he's losing to Hillary Clinton in Kentucky, this story mentions that Obama replied:

What it says is that I'm not very well known in that part of the country," Obama said. "Sen. Clinton, I think, is much better known, coming from a nearby state of Arkansas. So it's not surprising that she would have an advantage in some of those states in the middle.

Being an Illinois senator, you'd think he'd realize that not only is Illinois closer to Kentucky than Arkansas is, but that Illinois shares part of its border with Kentucky. Hopefully, this will not develop into a meme for him. Now, if you wish to make political hay over this, there's plenty of forums and sites that will let you comment on it (Any comments of a political nature here will not be posted).

My focus is on the fact that a mistake like this is surprisingly common. It might be the number of states, or forgetting the name of some of the states (much easier to do), but there a number of mistakes to be made about the states.

Not long before the above speech, Stacy Kate of the Hello...This Is Me blog had mentioned an episode of Friends I'd never seen or heard about. It was a Thanksgiving episode where Chandler challenges everyone to name all 50 states, and it becomes torture for Ross who can't remember all 50. It was called The One Where Chandler Doesn't Lie Dogs, and you can see it online, with Part 1 here and Part 2 here. Note that most of the characters miss one or two, and Joey gets 56!

Naturally, I'm always on the look out for ways to help others improve their memory about the states. One of my favorite tools for this has always been, of course, Wakko's 50 State Capitals song from Animaniacs (and even he makes a mistake at the end!).

A newer way to remember the states is the rather ingenious 50 States of Mind website. In the opening graphic, you can click on any state, and you'll see an unusual graphic in the shape of that state. While they are unusual, the graphics are mnemonics for facts about that state. For example, Pennslyvania is shown as a bag full of pens and pencils, with a star on the bag marking the capital, Harrisburg, and the store logo on the bag being from a company called William's Pens and Pencils, to help you remember Pennsylvania's founder, William Penn.

Some of the state pages, like the one for Colorado, have a starred button next to the state. If you roll your cursor over those stars, you will see a state map imposed over the graphic. At least there's no mistakes on this si . . . wait . . . the rollover graphic shows the correct capital, Denver, but the caption above the state says the capital is Boulder!

So far, these state links are proving to be good reason to double check your geography knowledge before presenting it.

As long as we're having fun with state mistakes, I'd like to wind up with a few of my favorites. The first one comes from a news story about the state of Georgia's first execution in 7 months. As it is now, there's nothing wrong with the story, but when it was originally posted, the story looked like this:



The included map, if you can't tell, is of the country of Georgia, not the US state.

Of course, if you're wondering why so many Americans have trouble with their geography skills, there's really only one person to ask – Lauren Caitlin Upton, better known as Miss South Carolina Teen USA 2007:



To be fair, she has played off her unfortunate fame from this in, what I think, is one of the smartest moves she could have made. She paired with People Magazine to create this interactive geography quiz. It's interesting to laugh at her goof one minute, then have her best you in geography knowledge the next.

So, how confident are you in your knowledge of all 52 states? (Yeah, I had to make at one mistake in this article on purpose.)

While I enjoy many types of puzzles, I grew up as an '80s kid, and will always have a special place in my heart and mind for the now-classic Rubik's Cube. There were, and still are, some excellent books on solving and even speed solving the Rubik's Cube, but I've never felt that books were the right medium for teaching how to solve it.

Early on, the internet as a whole, and even the web in particular, wasn't well suited for teaching explanation, either. However, thanks to technologies like Java, and the explosion of video technology, the web has become an excellent resource for learning about the cube.

As many of you may already know, the cube has 43,252,003,274,489,856,000 (over 43 quintillion) possible arrangements. What might be surprising to you is that it has been proven that none of these arrangements require more than 26 moves to solve. If you already know how, you may get lucky and solve a particular arrangement in less than 26 moves, but doing consistently would really only be possible with an extraordinary amount of memory or time, referred to by puzzlers as God's Algorithm.

If your interest is in just being able to solve the cube, you won't need to worry about the time or total number of moves. An excellent general solution can be found at How To Do Things: How To Solve a Rubik's Cube. Besides giving clear instructions and excellent examples of the various moves, this article also gives you a great idea of what to expect when you move on to more advanced solutions.

This basic method can be further clarified with help from Wikibooks: How to solve the Rubik's Cube and the videos at 3x3 Rubik's Cubes For Dummies.

If you decide you want to bring down your total number of moves, ScienceHack features a video that gives you a method for always solving the cube in less than 100 moves. While you're there, you may want to check out their one-part video and part 1 and part 2 of their two-part solution videos, as well.

To improve from there, the best resources can be found in the earlier-mentioned How To Do Things article. The Fridrich Methodand the Petrus Method are excellent for developing your speed cubing. Once you've gained some experience in it, you may want to move on to the Roux Method.

Of course, if you don't have the patience, and want a solution for the cube that's easy and quick, you could always try this approach. That link reminds me, there are numerous Rubik's Cube links over at grow-a-brain, if you're just looking for some plain old fun.

More and more news stories of interest to Grey Matters readers are crossing my desk, so it's probably time to catch you up on the news.

From the United Kingdom, we learn that brain training really can help boost your intelligence. Many people may have thought brain training games were a gimmick, albeit fun one, but there's now real science to back it up. If you'd like a better of idea of just how they help, eons.com has an in-depth post about the science behind brain games.

The United Kingdom sure seems interested in the topic of people's brains, because they've also looked into the average person's mental math abilities. It seems that, despite the fact that the average person needs to use basic mental math skills an average of 14 times a day, 25% of adults struggle with it. A study in Ohio suggests this is largely due to the use of concrete examples in math, which allegedly makes it harder to understand how to transfer those same math skills to other situations.

I lean towards the idea discussed in Kalid Azad's article A Gentle Introduction To Learning Calculus. He suggests that a major problem with math is that it is taught backwards, and suggests early teaching of the aha! moments from calculus concepts that make the concepts click. You should read the whole post, but Mr. Azad sums it up this way:

Imagine teaching art like this: Kids, no fingerpainting in kindergarten. Instead, let’s study paint chemistry, the physics of light, and the anatomy of the eye. After 12 years of this, if the kids (now teenagers) don’t hate art already, they may begin to start coloring on their own. After all, they have the “rigorous, testable” fundamentals to start appreciating art. Right?

There's a closely related article on the same site titled, How to Develop a Mindset for Math that I also highly recommend.

As today's final bit of news, Lifehacker recently posted a great list of their top 10 memory hacks. Each tip is given a brief description in the post itself, and then linked to sources where you can learn more about it.

It's been a while since I've really talked about magic, and since a number of free magic online resources have become available, it seemed like a good time to come back to it.

Without further ado, here are the free goodies:

• Maxime Nadeau's The Memorized Deck: This free PDF details two versions of a simulated memorized deck effect using simple sleight of hand, that's available. The effect is described in the PDF as follows:

Effect: The mentalist introduce a pack of playing cards, he is to show a proof of his incredible memorisation abilities. He hands the deck to a spectator which is requested to shuffle it at heart content. The mentalist takes the deck and spread it on the table, saying that he has photographic memory, whereby he can memorise the whole pack of cards and the position of each. The pack is handed back to the spectator and he is asked to say any number from 1 to 52. The volunteer replies the number 33. The mentalist concentrates and says that the card on the 33th position is the seven of clubs. The cards are dealt by the spectators, when the 33th card is reached, the spectator turns it over and indeed it is the seven of clubs.

• W. S. Andrews' Magic Squares and Cubes: Andrews' book is a classic from 1917, detailing more than you ever thought about magic squares (and, yes, cubes). It's almost too overwhelming to describe, so just click the link and read the PDF for yourself!

• MAGIC Magazine Electronic Index 1.6: MAGIC Magazine has had an electronic index available almost as long as they've had a website. For a long while, however, it only detailed the contents of issues through early 2004. After a long wait, they've finally updated it! It now details every article, news post, letter, trick, and feature up through October 2007! It can be used in just about any database software or office suite. If you don't already have an office suite for your system, you can get OpenOffice for free for just about any platform. Mac users can also download a version of OpenOffice that's specially designed to take advantage of OS X features, called NeoOffice.

As always, if you haven't seen the latest update of my Memory Effects PDF (March 14th, 2008), check it out and download it. Enjoy, and happy reading!

I started this blog on March 14, to coincide with Pi Day (3/14), and just celebrated my 3rd anniversary back in March. Today, however is another very special anniversary.

The first post on this blog was made on March 14th, 2005 at 7:03 AM. This entry is being posted on May 5, 2008, at 12:13 AM (28.7 seconds after the minute started), which is 3 years 51 days 17 hours 10 minutes 28.7 seconds later, or 3.14159265 years after the first entry! That's right, Grey Matters is now approximately Pi years old!

If this has you curious about how old you are in Pi, try the Pi Days site. Since Pi never repeats, you may also be able to find your birthday in Pi, as well!

To help celebrate this rather unusual occasion, I'd like to share some pi links with you:

The Joy of Pi: This is the site for the book of the same name, and has recently been redesigned. There's plenty of Pi goodness here!

Pi Day: An Infinite Number of Ways to Celebrate: OK, it's not Pi Day, but a Pi-versary is just as good a reason to celebrate, so feel free to steal some ideas from Pi Day!

Surprising Uses of the Pythagorean Theorem: Yes, you're probably very familiar with this equation, or at least believe you are. Why am I linking to it in a Pi article? Click the link, and learn about a new side of an old friend.

Mathematical Pi (to the tune of 'American Pie'): What's a celebration without a song? If you don't know the tune, you can listen to it, or even watch the music video!

Don't forget all the other Pi links I've posted over the years. Thank you for sharing this Pi-versary with me!

Now that you've learned how to move through quadrants and break up patterns effectively, let's practice and play an actual game!

Certainly you can play here, here, or here, or even on a regular board.

One of my favorite versions was Petri Kallberg's Knight's Tour 1.0 Dashboard widget (Mac OS X 10.4.3 or later required). I did, however, have a few criticisms of the widget. Instead of just sending off my criticisms, however, I decided to improve the widget myself.

The first thing that struck me about the widget was that all the squares were black. Not only was I used to a real chessboard with black and white squares, but the advanced version I teach requires that you know which squares and black and which are white. Naturally, that was the first change.

In the original widget, the black squares hadn't been visited, and the white squares had been. The second change, then, was to add a new color for visited squares, for which I chose a deep blue.

The original version also featured a great concept, that of showing the valid moves from your current square. I liked this, but I also wanted to be able to demonstrate the Knight's Tour without this feature. I decided to make it an option. There is now a Valid Moves? checkbox on the back. When the widget is loaded or restarted, this will default to off, but can be activated on the back of the widget, and it will take immediate effect. As in the original version, the valid moves will show up as grey squares.

Also, I've added messages for two particular situations. The first, of course, is when you complete the Knight's Tour, where you get congratulations. The other message appears when you leave yourself without any moves. It notifies you that you're trapped, and tells you to restart.

The result is my Knight's Tour 2.0 Dashboard widget (Mac OS X 10.4.3 or later required), which is downloadable at that link, or via the Download section in the rightmost column for free. Here is a screenshot of this new version (shown with the Valid Moves option on):

If you're a Mac user, try it out, and let me know how you like it!

Regular readers will expect my next post to be around noon on Sunday. However, I'll be posting very early Monday morning instead. Why the unusual posting time? You'll have to wait and find out.