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:
Guar gum solution crosslinked with sodium tetraborate
Pancake batter
and Dyed glue crosslinked with sodium tetraborate.
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.
As 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.
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.
Like I’ve told you once, there is no pink. Still, we do see the colour pink and there’s no denying that. Don’t call me a sexist for saying this, but it’s true that the colour pink is associated with femininity. Otherwise the colour is also known to generate feelings of caring, tenderness, and love. If everything we know about pink is somewhat positive, then why isn’t it a good idea to paint your walls pink?
Let me start with a little story.
Hayden Fry and the Pink room
Hayden Fry was an American football player and later he went on to become a coach. In the late 70s he started coaching the University of Iowa football team. Now, the particular thing to note about Fry was that in the year 1951 he had graduated from Baylor with a degree in psychology.
Since he had graduated in psychology, Fry probably knew some good ways that he could use to mess with the opposing team’s brain. And then he decided to paint the walls of the visitor’s locker room at Iowa’s Kinnick Stadium, with the colour pink. The walls, floors, toilets, ceiling and everything else in the locker room was painted pink. As a result, the home team started doing significantly well at football games (later the practice of painting locker rooms pink was outlawed).
Some say, he used pink to paint the visitor’s locker room because he knew that the colour pink had a calming effect on people. But I think he was relying on something deeper. He was probably trying to cash on the results of a study that was done by Prof. Alexander Schauss in the year 1979.
The Effect of Pink Colour
Prof. Alexander Schauss started a study with a couple of volunteers. He divided the group into two equal halves. All of their strengths were measured by asking them to use their arms against a counter-force and by asking them to squeeze a device called a dynamometer.
After this, for a minute, the first half had to stare at a dark blue colour and the other half stared at pink. Their strengths were recorded again.
A remarkable decrease in physical strength was recorded among the people who were given the colour pink to stare at. The participants were not aware of the effect it had on them.
Probably it were those pink walls and pink floors at the visitor’s locker that made the opposing team physically weaker and helped Iowa win.
Conclusion
Colours certainly are one of those subtle forces which change the way we think, feel, and behave. Pink has been proven to make you weaker physically. So, unless you wish to be weaker, you wouldn’t want to paint your walls pink! How about blue? It is a simple choice.
Now I think even writing an article about pink and having your brain think about the colour makes you weaker. Seriously, I feel like I need rest after writing this. Phew!
In a wonderful paper titled “Unskilled and Unaware of it“, two social psychologists from Cornell University, Justin Kruger and David Dunning share an incredibly funny story of Mr. McArthur Wheeler. Although it is funny, the story actually beautifully demonstrates an excellent concept – a kind of cognitive bias (discussed later in the post). Here is the story:
The Story of Mr. McArthur Wheeler
On one fine morning in Pittsburgh (PA), in the year 1995, a man aged 44, known by the name McArthur Wheeler decided to rob a bank. Since he thought he knew a lot about a peculiar chemical property of lemon juice, he decided to smear the juice on his face before executing his plan to rob the bank.
His logic – As lemon juice can be used to write invisible letters that become visible only when the letter is held close to a heat source, he thought, the same thing would work on his face too. By smearing lemon juice all over his face, he thought that his face would become invisible to the security cameras at the bank. He did not just think that, he was pretty confident about this. He even checked his “trick” by taking a selfie with a polaroid camera. I’m not sure if the film was defective, or the camera wasn’t operated properly, but the camera did give him a blank image. The blank image made him absolutely sure that this trick would work. Or he would not have ever dared to rob a bank with lemon juice on his face.
That day, he went on and robbed not one, but two saving banks in Pittsburgh. A few hours after he had done his job, the police got their hands on the surveillance tape and decided to play it on the 11 O’Clock news. An hour later, an informant identified McArthur in the news video and contacted the police with the man’s name. McArthur got arrested on the same day. Ironically, the same surveillance cameras that he was confident would not be able to capture his face, got him behind the bars. During his interaction with the police, he was incredulous on how his ignorance had failed him.
The Dunning and Kruger effect
Both the psychologists Dunning and Kruger got story of Mr. McArthur. They decided to study it more deeply. The psychologists were interested to study about the utter confidence of Wheeler that made him believe he’d be able to foil the security cameras with lemon juice on his face. He had the confidence, but he clearly wasn’t competent enough…Why was he so sure he’d succeed?
Their study finally demonstrated that the less competent an individual is at a specific task, the more likely they are to inflate their self-appraised competence in relationship to that task. This phenomenon is today known as the Dunning–Kruger effect.
As Charles Darwin rightly said:
Ignorance more frequently begets confidence than does knowledge.
At zero experience in the x axis it’s not “no nothing”. It’s *Know nothing (There’s a spelling mistake in the image) – ‘On Finch’ mentioned this in comments below.
Indian Idol contestants and the Dunning Kruger Effect
This effect is clearly observed during the auditions of reality shows like Indian idol (etc). The auditions are usually thronged by a variety of good and bad singers. The ones who are bad at it, never realize their incompetence and yet are genuinely disappointed when they get rejected. Often times, they resort to noisy quarrels too.
If you’ve observed carefully, people who aren’t very good at humour or sarcasm often tell poor jokes and expect people around them to laugh hard. But when people don’t laugh, they seem genuinely shocked. It is incredible to see them totally unaware of how bad they are at it.
At every place, it is a common tendency of the least skilled people to have an inflated sense of self-competency.
Ignorance sure is a dangerous thing.
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Close your eyes: Before you watch this video, you should know that, when you watch it for the first time, you have to watch it with closed eyes. Well, you can’t ‘watch’ with closed eyes. It simply means, you have to just hear the sound track first. I’m sure you can do it because closing eyes for 5 seconds is not asking for much. I don’t have any veiled interests here. It is for you. You won’t appreciate the effect if you keep your eyes open during the first go.
Open your eyes: Watch it again with your eyes open. Be calm. It happens to everyone.
So that was the McGurk effect. It is a perfect example to show that accurate perception of reality may involve more than one sense. This is called “Multimodal perception”. In simple words, our senses do not learn from the surroundings independent from each other, they work together and learn together to help us perceive information.
The video
The video shows a man moving his lips as if saying “Ga” or “Da”, although it is just a visual of him saying that, let us call this the visual for the first sound (“Da” sound). The second sound is the “Ba” sound that is actually playing – this is the second sound.
When your eyes are closed, you hear the correct sound, the second sound – the “Ba” sound.
When you watch it again with your eyes open, you hear the “Da” sound. The brain combines the visual and audio signals to make you believe that the sound you are hearing is actually “Da”. Even if you are aware of this illusion, your brain doesn’t correct it for you, no matter how many times you repeat this.
Some interesting things about McGurk effect
You can focus anywhere on the face (not just the mouth) to perceive the same effect.
Women show a stronger McGurk effect than men.
Normally, people with mental disorders do not hear much difference in the sound with eyes open or closed.
By the age of 4 months, infants are able to identify facial movements and relate them to sounds. So, even infants show this effect to a certain extent.
Information rich perceptions are easier to remember. So, the next time you are trying to learn something, involve more senses. Probably involving a particular smell that goes with a piece of information will help you remember things well. Or a sound, maybe.
Note: Since my posts were getting longer everyday, I’ve tried to keep this one short. I don’t want the posts to be overwhelming for people who are not used to long reading. This blog is meant to make science sound interesting to everybody, not to scare them away from it. I’ll be waiting to receive your feedback on this. You can get in touch through twitter (@indigoanalysis)
In the past, we have seen that when it comes to estimating temperature, we are not so smart. Once again seeing the Mpemba Effect defying all known logic, reminds me to be careful about applying logic to most of the natural phenomena which are seemingly simple but in reality are extremely complicated.
By applying simple logic, a 7-year-old could tell you that cold water should turn into ice quicker than hot water would. It should, because a hot liquid contains a lot more heat as compared to a colder liquid, which [the heat] has to be removed in order to freeze it. Yes, it is what anyone who is unaware of the Mpemba Effect would think. But, that isn’t the case with water. It turns out that a very common substance – water – is not as simple as it looks.
Mpemba Effect
Since the time of Aristotle and Descartes, scientists have noted that hot water can freeze faster than cold water (and yet the effect is not popularly known among us today). Although the effect was noted back then, the actual mechanism which caused it remained a mystery all along…until the year 2013.
All this time this effect must have been known by some other term because, it was not until the 1960s it was named “Mpemba effect”. It was named that after a Tanzanian cookery student Erasto Mpemba when he observed that hot ice cream mix froze faster than the cold mix.
Several theories have tried to explain the mechanisms that cause the Mpemba Effect. Not even one of them was convincing enough. Probably this is what propelled the geniuses from Singapore who could finally solve this mystery during the month of October this year.
What causes it?
In simple words, Hydrogen bonds cause this effect – faster freezing hot water. Normally, individual water molecules are connected by this bond called the Hydrogen bond. Think of the water molecule as a string with two bullies – hydrogen bonds – one on either side. These Hydrogen bonds pull this string from both sides. As a result, the string stretches. We’ve all fought with rubber bands and know that a stretched string has a butt load of energy stored inside it. The same thing happens with water. Energy is stored in stretched water molecules at normal temperature. This extra energy has to be removed to cool water.
At a higher temperature, the heat kind of weakens these bullies. So, the weak bullies aren’t able to pull the string as much. Now, individual molecules sit apart. They are no longer stretched. Thus, not much energy is stored in these strings anymore. They have given up energy. There is no longer any extra energy that needs to be removed. Hence, cooling is faster.
Sorry: Today I don’t have my buddy – the internet – with me. So, you won’t see any outgoing reference links today. I have a just a bit of internet (a slower 2G connection) which I’m using up to publish this.
I talked about a light that utilizes the power of gravity to light up a few days back. This flashlight is a bit similar in a way that, it also doesn’t need any batteries. But the underlying mechanism it uses, is completely different.
The winner of this year’s Google Science Fair, in the age group of 15-16, was a 15-year-old girl from Canada, Ann Makosinski. In her project she created a flashlight that, instead of batteries, uses our body heat to light up. She calls it “Hollow Flashlight”
The flashlight uses 4 Peltier tiles to convert the temperature difference (between body and room temperatures) into energy. One side of the tiles is heated by our body heat and the other side is at room temperature. This temperature difference creates electricity using the Thermoelectric effect. The tiles used for this light need a minimum of 5 degree difference of temperature to work.
Peltier Tiles
Peltier tiles utilize thermoelectric effect to convert temperature difference into electricity. When there is a enough temperature difference, charge carriers move from hot area to the colder area. This separation of charges builds up a potential difference across the height of the tile. This potential difference can be used up for various things. In this case, it was used to light up LEDs.
Advantages: The amount of potential difference produced depends on the material. Peltier tiles are great because they are compact and they do not use any moving parts. Elimination of any moving parts eliminates wear and tear. They last long and do not need a lot of maintainance. However, their efficiency is not so great. So, they are used only where long life is essential.
The Voyager space probe and other deep space probes, where long life is of prime importance, use Thermoelectric generators (another image). The heat there is produced by a radioactive isotope. Implanted pacemakers which require long life also use it as a source of energy. All of them work utilizing the same effect – thermoelectric effect. The eco-fan, a wood stove fan, also uses the same effect in a very creative way.
