The Langton’s Ant

By Anupum Pant

Think of a cell sized ant sitting on a huge grid of such white cells. The thing to note about this ant is that it follows a certain sets of simple rules. The main rule is that when the ant exits a cell, it inverts the colour of the cell it just left. Besides that:

  1. If the ant enters a white square, it turns left.
  2. If it enters a black square, it turns right.

Here’s what happens if the ant starts out in the middle and moves to the cell on the right, as a starting step (this can be on any side).

First step, it goes to the right.
First step, it goes to the right.
Enters a white cell and rule 1 kicks in. The exited cell is inverted in colour and it turns left.
Enters a white cell and rule 1 kicks in. The exited cell is inverted in colour and it turns left.
Enters a white cell and rule 1 kicks in. The exited cell is inverted in colour and it turns left. (Again)
Enters a white cell and rule 1 kicks in. The exited cell is inverted in colour and it turns left. (Again)
Enters a white cell and rule 1 kicks in. The exited cell is inverted in colour and it turns left. (Again)
Enters a white cell and rule 1 kicks in. The exited cell is inverted in colour and it turns left. (Again)
Enters a black cell and rule 2 kicks in. The exited cell is inverted in colour and it turns right.
Enters a black cell and rule 2 kicks in. The exited cell is inverted in colour and it turns right.
Rule 1 again and so on...
Rule 1 again and so on…

Now as this continues, a seemingly random figure starts taking shape. The black cells are in total chaos, there seems to be no specific order to how they appear on the canvas. (of course the pattern is always the same chaos, considering the ant starts on a blank array of cells).

And yet, after about 10,000 steps are completed by the turing ant, it starts creating a very orderly highway kind of figure on the canvas. It enters an endless loop consisting of 104 steps which keeps repeating for ever and creates a long highway kind of structure.

Suppose, initially you take a configuration of black spots on a canvas (not a blank white canvas). Take an array of cells with randomly arranged black spots, for instance. If given enough time, the ant ultimately always ends up making the looped highway. However, before it starts doing it, it might take a significant amount of steps less, or more, than the ~10,000 steps it took to reach the loop in a blank array of cells.

No exception has ever been found. A computer scientist Chris Langton discovered this in the year 1986.

The Landolt Clock Reaction

By Anupum Pant

Steve Spangler Never ceases to amaze me. Once again I found this old video of him on the Ellen show. These are a few experiments he does on the stage…

  • Lights a tube light with his bare hands and Ellen’s.
  • A transparent liquid suddenly instantly changes colour.
  • Blows the hydrogen and oxygen mixture on Ellen’s hand.
  • And makes someone from the audience walk across the table on a non newtonian fluid.

Steve doesn’t exactly explains what happens there, but the second experiment is my favourite. It is the one in which he asks Ellen to pour two transparent liquids into each other and mix them well. Then Ellen waits for a few seconds and the liquid instantly turns into an ink like colour.

The magical effect is actually a chemical reaction known as the Landolt Clock Reaction. It actually involves 3 different solutions (read about them). The reaction happens quicker once the mixing starts and leads to a third reaction which happens immeasurably fast. It’s totally instantaneous and thus the transparent solutions turn into a bluish black iodine starch complex. As steve’s website puts it…

The sudden change from a colorless solution to the blue-black solution is the result of four sequential reactions. First, the bisulfite ions (HSO3-) reduce some of the iodate ions (IO3-) to form iodide ions (I-). Next, the iodide ions (I-) are oxidized by the remaining iodate ions (IO3-) to form triiodide ions (I3-). The solution now consists of triiodide ions (I3-) and soluble starch. In the third reaction, the triiodide ions (I3-) get reduced by the bisulfite ions (HSO3-) to become iodide ions (I-). That continues until all of the bisulfite has been consumed. Finally, the triiodide ions and starch combine to form the dark blue-black starch complex that looks like ink.

See more at: SteveSpanglerScience

It Sure is Magnetic, But is it Solid or Liquid?

By Anupum Pant

Figuring out if glass is a solid or liquid is pretty straight forward. This putty in the video however, behaves a lot like pitch (the same thing that was used for the world’s longest continuously running experiment). On applying a greater and abrupt impact, it shatters like a ceramic. While it flows like a liquid if you let it. But that is not even the point.

The point is, it can be magnetized! And it sure is another one of those awesome science toys you can have on your desk all the time. By the way, the other ones are Gombocs, constantwidth objects and feel flux. It must so much fun to play around with such a gooey magnetic material (putty). Some good soul will gift it to me for my birthday…may be.

It stretches, bounces, breaks, flows, can be magnetized and what not! It’s like the ferro fluid, but more awesome. Even this, like ferro fluid, has very very tiny magnetic particles dispersed in a putty like substance which makes it magnetic.

Who wouldn’t want to try out that Neodymium magnet swallowing trick! Since it looks like it’s live, they call it the magnetic thinking putty. Perfect name, I must say.