Bacteria Based Computer

This interesting piece appeared recently in the Guardian Science Blog. Bacteria were used to create a working computer. They gave it the Hamiltonian Path Program which very simply is finding the best route that goes through a specific number of cities.

"[The] problem is surprisingly difficult to solve. There are over 3.5 million possible routes to choose from, and a regular computer must try them out one at a time to find the one that visits each city only once. Alternatively, a computer made from millions of bacteria can look at every route simultaneously."

The scientists did mention that programing the bacteria is pretty difficult.

An interesting side note to this story was the mention of a database of the basic biological designs for these types of machines called the Registery of Standard Biological Parts. I looked around this site for a while and it was facinating. It quickly went over my head, but all the parts and concepts that have already been developed was mind boggling. It's kind of like looking through an electronics catalog. You don't know what all the parts are for or how they are made, but you still look and wonder.

Link to the original article in the Journal of Biological Engineering.

[Image captured from http://www.guardian.co.uk/science/blog/2009/jul/24/bacteria-computer]

Introducing the Macintosh (1984)

I fondly remember going with my friend Steve in mid eighties to go pick up his new Macintosh. We both had Apple IIe's and were excited to actually get our hands on this new kind of computer. Steve was (and is a musician) and was buying the Mac because of some of the music software available (maybe Finale.....I'll have to ask him next time we talk). I was excited, well, because even back then I was kind of geeky.

We unpacked it and had it up and running after installing many disks worth of software. One floppy at a time. I was blown away by the graphics. Amazed by the mouse. In love with the simple drawing program (MacPaint) that came with the machine. I left that day wondering how long it would take me to save up enough money to get a Mac.

It's hard for folks who weren't into computers back then or too young to understand what a shift in technology that machine represented. I realized the other day that all of my students have grown up with graphical interfaces. Then I realized how old I was getting to be. Then I had to rest from all the thinking.

Here is a YouTube video of Steve Jobs presenting that Mac 25 years ago.



Here is the famous Mac commercial that aired only once during Superbowl in 1984



[via Free Technology for Teachers]

[Image: Captured from Wikipedia: http://en.wikipedia.org/wiki/File:Macintosh_128k_transparency.png]

Marble Adding Machine

Saw this Binary Marble Adding Machine on the Nuts and Volts site I posted about recently. I've watched the video several times now and am fascinated by the mechanical action.

Fun to show in a math class or a programming class. The author had this to say about how he designed the rockers.

"Also tricky was getting the rockers to consistently work. I spent a lot of time figuring out what dimensions to make them so that they would correctly work, even if two marbles arrive onto the rocker right on top of each other. I knew it was physically possible to build such a rocker, because the lego rockers I built into the original Lego marble machine had this property by a fluke. The trick turned out to be to make peak of the rocker, which divides the marbles, short enough, and the rocker shallow enough. That way, if a marble arrives before the rocker has had a chance to flip, the previous marble, which is still on the rocker, will deflect the next marble onto the other side, even if the rocker has not yet flipped. "

The web page has lots of closeup photos and design explanations.



[Image captured from http://woodgears.ca/marbleadd/]