The Weissenberg Effect

By Anupum Pant

Remember the time we talked about a boiled egg spinning on a pool of milk? If you don’t then it’s good to know that if you do spin a hard-boiled egg on a pool of milk (or any relatively viscous liquid) the milk mysteriously climbs the side of the egg, reaches the equator, and then sprinkles around beautifully. It’s fun to see it happen. This is something similar…

The thing we see today is called the Weissenberg effect and this is how it works.

You take a spinning rod and put it into a solution of liquid polymer (which is usually very viscous). And when you do that, you see that the liquid polymer magically climbs the walls of the rod.

Some liquids reach a little high and never beyond. While others can climb up really high. The difference in heights to which different liquids can climb to is demonstrated in the following video very clearly. The three liquids used in it are as follows:

  1. Guar gum solution crosslinked with sodium tetraborate
  2. Pancake batter
  3. and Dyed glue crosslinked with sodium tetraborate.

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Lightning Trapped Forever in a Box

By Anupum Pant

On a cloudy and stormy night (or almost all the time, in this part of Venezuela), dark clouds separate charges and are able to put together the right conditions to send off one of the nature’s most powerful forces from the heavens – lightning.

The air break downs and a great amount of static charge gets transferred through the path of least resistance. And a bolt of bright light is seen for a fraction of a second. It lasts for a very little time.

lichtenberg-figureAs it happens too quickly, the exact shape of a lightning bolt is difficult to see. However, a long time back, a German physicist, Georg Christoph Lichtenberg, figured something that could help make the lightning bolt last longer. Or in fact, it could trap the lightning tree-pattern forever in an insulator (eg acrylic or wood etc.). The tree-like figure is called the Litchenberg figure after the person’s name (Georg Christoph Lichtenberg) who first noticed this.

Isn’t it a nice sculpture to have – a block acrylic with a lightning bolt permanently trapped in it! Or may be it could be a great gift for your physicist friend. But, sometimes the litchenberg figure isn’t a desirable thing to have…

People who unfortunately end up getting hit by lightning, sometimes survive to this permanent tree-shaped scar mark (or tattoo) – A permanent litchenberg figure gets printed on their skin. It looks like this.

litchenberg figure on skin

The Leaping Shampoo Trick – Kaye Effect

By Anupum Pant

This is really interesting and I can’t explain why. You’ll have to see it for yourself.

Long time back, researchers at the University of Twente in The Netherlands thought of something very weird. They decided to drop a thin stream of shampoo from a height of about 20 cm, ended up discovering an absurd physical effect and winning great accolades for it – The Kaye effect.

The seemingly weird effect can fairly easily be achieved at home by dropping a thin stream of shampoo on a relatively hard surface. In individual steps, this is what happens when you do it:

  • As the stream gets collected, it forms a little shampoo heap.
  • Amazingly, and counter-intuitively, a secondary stream ejects off the heap.
  • The mythical secondary stream becomes bigger, shoots further.
  • And finally hits the incoming stream – this collapses the Kaye effect.

Of course, everything happens really fast. But, if you look at it on extremely slowed down film, you’d see the individual steps happening one after the other.

True, the secondary stream collapses too quickly, scientists weren’t happy about that either. So, they tried tilting the hard surface slightly to achieve a stabler version. Lo! And they had a stable Kaye effect.

This happens because due to certain physical forces the viscous liquid becomes slightly less viscous temporarily – they call it shear thinning. As a result, it causes a new stream to emerge. May be the same effect could be achieved with other thicker liquids like lava, ketchup, whipped cream, blood, paint, and nail polish. But, then lava is too dangerous, and others (barring blood and paint) seem to be too thick. I’m guessing, dropping thicker ones from a higher place could make this happen.

If you find this interesting,you’d definitely love the egg and milk effect, also the chain of beads defying gravity.

Here, watch it on video.