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Shot Towers

By Anupum Pant

The way of making lead musket balls before 1782 involved a lengthy process. And if you had a huge army, then you were in for a massive task. To make each ball:

A chunk of lead was melted in a crucible
Poured into a mould
It was let to stand to solidify
The mould was broken
Final finishing of each ball was done
and each ball was checked for roundness by rolling it on an inclined plane

Then everything changed in the year 1782, when a plumber from Bristol William Watts, got this seemingly simple idea – Drop molten lead from a long tower and let the surface tension do the work.

He got this idea by observing raindrops, which formed perfect spheres while they were free-falling. Before telling anyone about it, he tried implementing his idea. He dropped molten lead into a bath of water from the tower of his local church. It worked perfectly.

He did a couple of other experiments at home and finally patented his idea by the end of the same year. It wasn’t long until shot towers started sprouting all over the world. William made a good fortune out of this.

A shot tower is a long hollow building, like a light house, which has the machinery to melt lead at the top point. The molten lead is dropped into the long hollow shaft through sieves, and the bottom part of the building has a bath of water to catch lead balls. The free falling lead turns into a sphere due to surface tension and solidifies in air due to flowing air. After shots are made, they are lifted from the water and checked for roundness by making them roll on an inclined plane. Defective ones are sent back to the top.

The tallest shot tower ever built was 263 meters long and was constructed in the year 1882. It still stands in the Melbourne suburb of Clifton Hill in Australia. There are several others around the world which are still standing. While many others have either been destroyed by men or nature.

via [PSSA]

Up or Down – Cats in Space

By Anupum Pant

Cat’s righting reflex

Thanks to the Vestibular righting reflex, animals like cats are able to land on their feet after a fall. This is great because it helps them avoid injury. In fact, it helps them avoid injuries in a very counter-intuitive manner.

In a study done in the year 1987, researchers found that cats falling from 6 storeys or less usually have greater injuries than cats falling from places higher than 6 storeys. There have been cats who have survived a fall from as high as 32 storeys. It’s so absurd, I had to mention that.

Also cats have been often found falling from high rise buildings due to a phenomenon known as the high-rise syndrome. This happens because cats mostly have a natural attraction towards high places, often get distracted by a prey and fall.

Cats In Space?

All said, there’s no doubt that cats can right themselves pretty well. But to do it, they need to have a sense of what is up and what is down. That sense, of course comes from gravity. What happens to them in micro gravity? A little kid asked me that and I had no answer. Who would have tested that, I thought.

So I checked. To my surprise, cats-in-zero-gravity-tests (simulated weightlessness) have actually been done previously by the USAF medical division and Russian cosmonaut training centre. Here’s an interesting old video of how cat’s natural reflex to right itself by spinning longitudinally fails in a simulated zero-G environment. The video also has confused pigeons flying upside down in zero-G. The whole film can be seen here.

Through experimentation it has been found that when it comes to animals in space, there are three different kinds of behaviours seen among various animals.

The first ones are the kind of animals who freeze in zero-G and wait for the weightlessness to go away. There are others, like cats and pigeons, who start moving about madly, trying to figure out which side is up. In fact, pigeons in zero-G have been seen flying upside down too. And the third ones are who stay calm and find the best way to move around.

Geckos have been seen to take on a free-falling stance in zero-G. Fish and fruit flies are some of the creatures who can deal with zero-G very well.

And if you wish to see some long slender legs before you go, here is a video of frogs in space. The video also talks about aliens entering the earth – tadpoles born outside the earth were brought back. Technically they were aliens and they entered earth!

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.

Outperforming Humans – Speed

By Anupum Pant

Humans can use tools, communicate, count, make others laugh, socialize and are self aware too. We also have emotions and a pretty good memory. All of the things put into a single creature sure makes the “most advanced” creature we’ve ever known. But if these traits are considered individually, you’ll easily find an animal who beats us at one trait at a time. Today, I wanted to read and write about where humans stand when it comes to speed.

Talk about running speeds and the fastest person ever, Usain Bolt comes to my mind. A bolt indeed. As on date, if I’m not wrong, the world record set by him in the 100m race is 9.58 seconds. To put this human freak show into perspective, the average speed of the Jamaican sprinter in this race comes to about 37 km per hour (23 miles per hour). And he’s clocked 28 mph somewhere in the race, they say.

In a world full of cars and planes, where distances travelled have become really huge, 28 mph sounds like a speed which does no good in our practical lives. And yet, it takes an Olympic runner to clock that speed. Normally, people run at about, say 10 mph. Damn!
The biological human limit to running speeds is estimated to be about 40 mph.

Quick fact: The fastest human objects ever are Helios 2 (a German probe) clocks about 150,000 mph. Another spacecraft, Juno does about 25 miles in a single second!

Now compare that with a Peregrine Falcon which can make use of the gravity and its perfectly aerodynamic body to travel at a speed of 216 mph (360 kph). But, that’s hardly any work for the animal. It’d the gravity making it fall.

In level flight, the white throated needletail (swift) can fly at speeds more than 100 miles per hour (up to 106). That’s the fastest bird if you do not count gravity assist.

An on land, of course the Cheetah takes the prize with about 70 mph of running speed. But, there’s a catch. If you measure speeds of animals relative to their body sizes, there’s a little blood sucking mite that beats cheetah by a huge margin.

The fastest swimming fish is the sailfish, which can swim and jump for small distances at about 70 mph.

Humans can swim at about 5 miles per hour.

Moving at 35 miles per hour a jack rabbit can travel faster than a human. The patas monkey, the fastest primate, runs at about 35 miles per hour too!

Now these are some animals you probably already know. Soon there’s more to come. In the coming days I wish to do a series on outperforming humans…Maybe I’ll write about endurance next.

Keep reading for more.

Prince Rupert’s Drop – Exploding Glass

By Anupum Pant

What is it?

At first, a Prince Rupert’s Drop is an interesting yet harmless looking drop of glass with a long tail. It looks like a tadpole: [image]

It is no different from an annoyed person who refuses to let out his resentment – A slightest something might make him explode suddenly, but it isn’t easy to make him let it out. Confused? Read on…

Now, think of a glass drop that has immense amounts of potential energy stored inside it – It explodes (actually implodes) when the tail is disturbed, but it is impossible to hit it hard with a hammer and break it.

How?

A Prince Rupert’s Drop is formed when a drop of molten glass is suddenly dropped into a water bath. This quick cooling, solidifies the surface fast, while the inner part remains molten. Now, glass formed on the surface, being a poor conductor of heat doesn’t allow the inner part to cool quickly. When the inner part starts cooling, it tries to shrink and pulls the surface towards it. As a result, great amount of potential energy gets stored inside, in the form of stresses (stresses are seen using a polarized filter). This stored energy gets released when the tail is disturbed – It explodes into very tiny pieces of glass.

Toughened glass – a stronger variety of glass used in several places – also uses a similar technique to make strengthened glass.

On Wikipedia, a user asked about the possibility of utilizing the energy released from this explosion, being used to fire a bullet from a barrel. An interesting possibility, I must say.

The Name

Prince Rupert of Rhine did not discover the drops, but played a role in bringing them to Britain. He gave them to King Charles II, who in turn delivered them to the Royal Society for scientific study. Prince Rupert’s Drop was a widely known phenomenon among the educated during the 17th century – far more than now.

Watch it being explained better

Probably the best demonstration of this glass drop exploding is right here on the internet. Couple of months back, a YouTuber, Destin (Channel: SmarterEveryDay) posted a video demonstrating the physics behind it. He recorded the progression of the explosive fracture using a hi-speed camera (at more than 100,000 frames per second) and calculated the speed of the fracture travelling through its tail (~ 1.5 miles per second). I’ve attached it below for you to watch.

Longest Continuously Running Experiment – 83 Years and Counting

By Anupum Pant

An experiment so slow that a professor overseeing it, died without having seen the results for half a century! The Pitch Drop experiment, started by Professor Thomas Parnell of the University of Queensland in the year 1930, is the probably slowest science experiment and also holds the Guinness World Record for the world’s longest continuously running experiment ever.

What is the experiment?

It is an experiment designed to measure the flow of a solid looking piece (image) which is actually an extremely viscous liquid (actually a Viscoelastic Polymer) with a viscosity of approximately 230 billion times that of water. The name used for this class of extremely viscous liquids is, Pitch – Bitumen, Asphalt, Resin and Rosin are a few examples (not Glass). These things are so viscous that you can strike them with a hammer and see them shatter into sharp flakes (like glass), but it flows. The experiment is explained in detail, in the first few minutes of this radio show attached below. (the second half is pretty interesting too, but that is for some other day)

Other unbelievable materials previously covered in this series – Aerogels and Superhydrophobic surfaces.

Side note: The overseer of this experiment, Prof. John Mainstone actually lived through the drops of pitch falling three times, but unfortunately missed watching it happen every time (for 3 times in 50 years). In all, 8 drops have fallen since 1930.

1979 – He missed it because he wasn’t in the laboratory for the weekend.
1988 – Missed it because he went out for a tea break.
2000 – A camera was installed as a precautionary measure, the equipment malfunctioned; missed again!

He recently died waiting to see it in action. Since then, three web cameras have been installed as a fool proof measure to record the extremely rare event. You can watch it happening online here, although you might have to wait for several years to see it happening. (To confirm the live stream, look at that clock in in it and confirm with time here). There is also a time-lapse from 28th April 2012 – 10th April 2013 compressed into a 10-second-long video of the drop forming, embedded below.

A parallel experiment running at Trinity College, Dublin also wasn’t able to capture the rare scientific event on camera in spite of several drops falling since the commissioning of the experiment (1944). Finally, after 70 years of patient wait, on July 11, 2013 it was recorded on camera.

The Red Rain of Kerala

By Anupum Pant

In the year 2001, between 25^th July and 25^th September, people from the Indian state of Kerela (Kottayam and Idukki districts) experienced a bizarre oddity – The Red Rain of Kerala. Sporadic heavy downpours of mysteriously colored water left the people of Kerala dazed. More recently, red rains were also seen in parts of Sri Lanka between 15^th November and 27^th December, 2012.

Yellow, Black and Green rains have also been reported several times since 1896.

Red Rain of Kerala – Studies

A study conducted in India showed that the rain was colored because these raindrops contained millions of spherical and oval red particles which had an internal structure. These things looked like biological cells. Initially, when scientists weren’t able to confirm the existence of DNA (a fact which has baffled scientists) in them, in spite of an internal structure present in the cells, some started claiming that the origin of these red particles was extraterrestrial, possibly, coming from an exploded meteor.

Later the mystery was solved, the presence of DNA was confirmed and a study, destroying popular media claims, concluded that the red rain of Kerala had been colored due to airborne spores originating from a type of algae. There was nothing alien about it.

The unusual color of the rain was due to the presence of a unicellular micro-organism belonging to Kingdom Protista, of the Phylum Euglenozoa, known as Trachelomonas. Trachelomonas was the main cause of reddish downpours in other regions of the world as well.

[Source: The Red Rain of Kerala]