I'm still here!

If you're reading this, you may have noticed that I haven't posted anything for a LONG time. You probably won't hear from me very much in the future. But maybe I'll just decide to post something. Who knows? I'm here to tell you about an Android app that I've made and that is now available on google play! It's called BouncyZone. Basically, you make lines, and then you bounce a ball around on the lines and watch it go. Your downloads and reviews help a lot, so check it out at:

https://play.google.com/store/apps/details?id=com.blogspot.mathjoy.bouncy

Although I won't be posting much math stuff I'm still available for contact if you have issues with or suggestions for BouncyZone. Feel free to contact me about anything else you want. (mathjoy3.14@gmail.com) I can't appreciate anything more than your feedback.

How many Rubik's Cube combinations are there?

...Well, lets start off easier and ask how many ways you can put the stickers on. If you number the stickers of each color 1-9, so that all 54 stickers are unique, there are about 231 duovigintillion ways to put them on the cube. That's 231 followed by a whopping 69 zeros. Let's get more complicated and ask how many ways you can arrange the pieces on it (now without numbering them). There are 8 corner pieces that can each be turned in 3 ways while in one spot, 12 edge pieces that can each be turned in 2 ways, and there are the center pieces that never change position. With that, there are about 519 quintillion (519 followed by 18 zeros) ways you can arrange the pieces on the cube. In order to get the real answer for the number of combinations on a Rubik's Cube, you have to take into account the fact that you can't get to every arrangement just by twisting the cube. I don't quite understand the math for this part, but Numberphile has made a video about it, revealing that there are exactly 43,252,003,274,489,856,000 Rubik's Cube combinations, or about 43 quintillion.

Here's a few Rubik's Cube videos made by Numberphile:

http://www.youtube.com/watch?v=QV9k6dRQQe4&list=PLt5AfwLFPxWJNAdHv8TUCOmj7iKqyHZeg

How long would it take to figure out you iPhone pass code lock?

...Well, the most time it could possibly take to guess someone's pass code would be just over 5 1/2 hours, and that's if it took half a second to press each number and you tried every single possible combination and did it nonstop. Let's also ignore the fact that an iOS device locks you out if you get the pass code wrong too many times. Not to mention you're probably going to mess up at some point with 10,000 combinations. The way you would do it would be to start with 0000, then 0001, then 0002, and so on until you reach 9999. But then a lot of people will have repeating numbers for their pass codes like 9999, so it would be a good idea to try those first, not that you should actually try to break into someone's iPhone. See you next time, and don't spend 5 1/2 hours trying to break into someone's iPhone! It's not worth it!

P.S. If you saw when I had this post up before, I was completely oblivious to the fact that there was actually a 0 on the pass code keypad. All good now!

Science on the internet

There are several YouTube channels that are great for people who enjoy science and math, and even for people who don't. You can visit and subscribe to Veritasium, Minute Physics, Minute Earth, Smarter Every Day, Vsauce, Vihart, and Numberphile. You can view a page about them here. And here is a video by minutephysics about more science on the internet. Please check them out!

http://www.youtube.com/watch?v=i8t53Ak_yrQ

What is 0/0?

Because of school, I probably won't be able to post news during the week, so every now and then I might just post a short math fact, like this one. Most people when asked what is 0 divided by 0, would say 0 without hesitation. They even teach that in school, and I went several years thinking that until recently, but is that really right? Well, it's partly right. 1 infinitieth right to be exact. It turns out 0/0 equals anything you want. If you think about it, dividing is just figuring out how many times you have to multiply something to get a number. Since 0 * 0 = 0, and 0 * 1 = 0, and 0 * 1,000,000,000,000,000,000,000,000 = 0, these are all logical answers. Here's another way to prove it. If you graph a line with the equation y = x, the y divided by the x is always 1 at any point, so why should it be any different for (0, 0)? In fact, the y/x (or vice versa) is always constant for any line graph that passes through the origin, so the most logical answer for y/x at (0, 0) is whatever it is at the other points. So there you have it. 0/0 = any possible number you can think of.

Answer!

          Without all the math, here are the answers to gold questions. All the gold in the world would weigh 361,920,936 pounds. It doesn't sound as small that way, does it? (If you remember that it would fit in a cube with sides 67ft long) That would all cost over $8 trillion! Or $8,190,542,222,382 to be exact. Before the next answer, I want to point out that I messed up on the amount of storage space in a truck, which was really 4,006.4 cubic feet. It would almost fit in 75 trailer trucks, so it would take 76 to carry all the gold. You could make 1,565,992 solid gold bowling balls, each weighing 231 pounds. That's a bit heavy for bowling. Finally if you got about 348,000 of the world's strongest men, they might just be able to lift all the gold in the world.

All the gold in the world could fit into a cube with sides 67ft/20m long

          I couldn't think of a shorter title, so there you have it. I found that BBC News does this thing called 10 things we didn't know last week that is a list of 10 newly discovered facts. The 9th fact about gold (above the ground) just happened to be featured on a twitter post and it had a lot of math potential. We can answer questions like: How much does all the gold in the world cost? How much does it weigh? How many 53ft trailer trucks would it take to carry it using the maximum amount of space? How many solid gold bowling balls could you make? How heavy would each bowling ball be? How many Olympic weight lifting gold medalists would it take to lift it? How many more questions can you think of? If anyone actually wants to do any of these, here's some info: 1 pound of gold is 1.436 cubic inches. A pound of gold costs about $22,630.75 today, but it changes daily. A 53ft trailer truck has 4,006.4 cubic feet of storage space. A bowling ball is about 331.878 cubic inches. And finally, the Olympic record for weightlifting is 472kg which is 1040.288lb. Check back soon for the answer!