# Spark Feed

Sparks of insights from the world. Got a spark?

The longest vertical straw you can drink from is 10.3 metres. Even if you use a vacuum pump it won’t suck the liquid higher than that! Here is why!

Contrary to your intuition, when you drink from a straw you are not actually sucking up the fluid here. Just the air. So, when you do that, inside the straw, the pressure drops lower than that of the atmospheric pressure (101 kPa) outside. So, it’s the outside air pressure that pushes the water into the straw.

As the liquid moves up the straw, it is fighting against the gravity that is pulling it downwards. But it still keeps rising as long as the atmospheric pressure is greater than the pressure inside the straw due to gravity (weight of the liquid column).

The more liquid enters the column, the more it weighs. And at a certain height, there’d be enough water in the straw that’d exert the same pressure as that of the atmospheric pressure. That height, at sea level on earth, for water is 10.3 m.

$$p_{atm}= 101\;kPa$$

$$p_{straw}= \dfrac{F}{A} \Rightarrow \rho g h$$

$$\rho g h = 101 \times 10^3\;N/m^2$$

$$h = \dfrac{101 \times 10^3\;N/m^2}{10^3\;kg/m^3 \times 9.81\;m/s^2}$$

$$h = 10.3\; m$$

Playful aggression or cuteness aggression is the term for when one experiences an aggressive response to an adorable stimulus like a baby’s cheeks or a fluffy unicorn toy. The response is a harmless urge to pinch and squeeze a baby’s face. People would say something like “You’re so cute and I am going to eat you up!” in an aggressive manner, gritting their teeth or clenching their fists, but in a harmless and tender way.

This is similar to a stimulus of intense happiness evoking an accompanied negative emotion like crying to keep the hormones balanced.

Ever wondered if trees communicate with each other? They do, yes! It’s long known that trees trade nutrients, especially sugar, with the fungi that would reach out to their root system in exchange for nutrients from the soil. But recent discoveries from the experiments by a team of biologists, have also shown that these fungi form a deep network that connects neighbouring plants and trees and enables carbon, water, nitrogen, and nutrient exchanges.

Dubbed as the ‘World Wood Web’, the Mycorrhizal network (an underground network of fungal filaments called hyphae that branch out to the tree roots) is a biological network (also called as mycelium) that connects hundreds of trees.

The beauty of these symbiotic relationships is that they mutually help each other’s survival, acting as one big community—with bigger mother trees acting as hubs, protecting the younger ones. Nutrient exchange, warnings, immune responses, you name it! Sometimes trees of the same kind sabotage other trees with toxins and proliferate their species via a chained positive feedback network—resulting in a single species dominating an area. 👀 Just … like our World Wide Web! Wow!

In 1841, near West Roxbury, Massachusetts, there was a socialist utopian experiment led by George Ripley at a two hundred acre estate. Based on the principles inspired by Charles Fourier, educated men and women participated and carried out a shared communal life and labour, building a Phalanstère (a self-contained utopian building). But in March 1846, the building caught fire. Starting with a severe financial setback, the experiment eventually failed.

Ever wondered how dolphins, whales, and seals sleep if they require frequent surfacing to breath? Dolphins are known to sleep and stay conscious simultaneously as they lack autonomic breathing. They sleep close to the surface of the water, either by maintaining a steady swim pattern or just floating.

And during their sleep, they keep one eye open. In other words, only one hemisphere is at deep sleep while the other in a state of wakefulness. This keeps them 🐬 aware of their surroundings, alerts the time to surface for air, and maintains other conscious functions. This is known as unihemispheric slow-wave sleep. Fascinating!

Around 6th Century BC, the Persian empire had a very nifty way of counting battle casualties. Before any battles, the soldiers would be lined up in the presence of their battle commanders and generals. In front of them, a basket. With the emperor as the witness, they’d throw a single arrow from their quiver into the basket, which would then be sealed.

When the soldiers return, they’d be commanded to take an arrow from the same basket. The remaining arrows would then give the empire an estimate of the men they have lost in the battle. This is akin to the digital checksum process we use to verify the integrity of a file that’s transmitted over the internet.

What is that single, most basic stuff out of which all things in nature are made? This is one of the most fundamental questions that has intrigued humankind since time immemorial.

Thales was one of the first to have attempted to answer this question. He lived in the ancient Greek city of Miletus around 625 BCE, way before Socrates.

Thales’s answer to the question: Water. Everything consists of water, first comes from water, and goes back to water when destroyed. Water is that on which the earth floats, the most fundamental material, the ultimate ground of all things, the only permanent entity. He may have arrived at this conclusion from observing that most things depend on moisture for their existence. 💧

Why is Thales significant even today? However absurd his conclusion may sound right now, Thales is perhaps the first to have pursued this question philosophically—by explaining natural phenomena without any reference to external, supernatural beings. And, hence, this wise man is considered one of the first philosophers and Western philosophy is said to have begun with him.

P.S.: As ancient philosophy also included what we call ‘Natural Science’ today, Thales can also be considered one of the first natural scientists in the Western tradition. He is known for his theory of magnetism and for successfully predicting the eclipse that occurred in 585 BCE. 🧲⭐

If you have poured tea from a mug you’ll intuitively know what a Coanda effect is. To put it simply, the Coanda effect is the phenomenon where fluids like water tend to follow and stick to a contour of an object.

So what happens here? When the water flows out of the mug, the water molecules encounter the air molecules and try to drag them along due to viscosity. As the air molecules under the mug get dragged off, the pressure at that spot, which is relatively constrained compared to the other side, decreases (Bernoulli’s principle). And as the pressure is higher at the top of the water than on any other side, the water reaches equilibrium by moving towards the low-pressure region, which is what makes it to stick to the surface of the mug.

Most people think that inhaling helium changes the pitch or frequency of the voice. No! That is no what happens. It’s the timbre of the voice that changes.

When you inhale helium, the medium inside the vocal cavities changes from a dense medium, air, to a lighter medium, helium. And we know that in air, any vibrations travel at a speed of 343 m/s. For helium, it’s 1007 m/s. The helium medium now increases the natural frequencies of the cavities. In other words, it changes the responsiveness of the cavities to higher frequencies. This results in the amplification of a higher range of frequencies compared to that of when the air was the medium—causing the squeaky voice!

The key observation here is that the frequency at which the sound is produced by the vocal folds doesn’t change. It’s the resonant frequencies that change, forcing a change in the timbre of the voice.

On a ship through a rough sea, if you are inside the bridge, you’ll have a tough time getting a clear vision. Fog, condensation, waves of saltwater — everything competes to kill the visibility. Engineers found that conventional windshield wipers weren’t that effective against constant exposure to saltwater and continuous operation.

So the solution? It’s those small round installations like this you see on the bridge windshields. Better known as clear view screens. They are driven by an enclosed motor that disperses water droplets as it spins. It also heats up the glass to vaporise droplets, thus allowing a small window of clear sight ahead. Similar to the ones in CNC machines and locomotives.

Pretty cool! Some view is better than no view, eh? :)

Painters who got used to their mistakes would often look at their paintings upside down to spot the errors. You can apply the same for writings by changing the margin of the document or changing the font. I write essays and these small changes help.

RAM is a volatile memory. This statement is almost true but there is an exceptional case where it may not be. RAM sticks do not lose their memory instantly when you power down the computer. Residual memory takes some time to degrade. When the RAM is cooled down, it even takes a longer time; enough for an attacker to plug it to a live OS and dump the contents from the stick to a harddisk. This is a well known exploit called as the cold boot attack.

Christopher Columbus was not a hero like your school books perpetuate. He was a genocidal tyrant. According to ‘The Legacy of Columbus’ by Hans Koning (https://www.jstor.org/stable/29766672?seq=1), Columbus ruthlessly killed Native Indians. He burned them slow in rows and mutilated anyone who rebelled. His followers hunted the natives who fled and fed them to their dogs and sold them as dog food in butcher shops.

Hans Koning also writes about the tribute system Columbus practised in Hispaniola. In order to find the gold he promised to the monarch, he forced Indian slaves to collect the gold dust from the river streams. For those who brought gold, a copper token was tied around their neck. For the Indians without the token Columbus had their hands cut off and had them wear the amputated hand around the neck!

After he failed to find the gold, he took the slaves to Spain and got them killed. He later introduced the encomienda system where his followers grabbed the lands of the natives and enslaved them as their slaves for labour and sex!

Not everything you learn in school is true! It is a shame that this despicable monster is honoured with city names and national holidays!

If you are in space and shine a torch in an arbitrary direction, the photons (although being massless) will impart a thrust on you that will propel you in the opposite direction. This is due to the conservation of momentum as well.

In other words, when photons are ejected out of the torch, they travel outward with a momentum*. And due to this, your momentum changes to conserve the total momentum of your initial state, pushing you in the opposite direction.

* Photons have a relativistic mass and they do have momentum, given by $p = \dfrac{h}{\lambda}$.

Have you ever dipped your toes into a river? And then tried to do it again? You can never step into the same river twice, says the ancient Greek philosopher Heraclitus. The river remains the same, but it constantly changes as its waters flow. 🌊

The cosmos, too, is like the river. There is constant change, but there is also an underlying unity to that change. This unity, Heraclitus called the Logos—an order to the world that controls its happenings.

How can one understand this? By using one’s reason to properly interpret the information one gets from the senses, says Heraclitus.

Contrary to popular belief, polar bears don’t have white skin. Their skin is black underneath all that white fur, which is likely evolutionary to absorb more heat from the sun. You can see this around their nose or under the paws. But did you know that they aren’t always black? When they are born, they have a pinkish skin which only turns black after a few months.

There’s a constructed language called Esperanto that was invented by Dr Zamenhof around 1887 as a proposed common language that’s much simpler than other languages—with just 16 rules for grammar.

Strongly based on the European languages, It has 28 alphabets and simple rules like nouns end with ‘o’, adjectives with ‘a’, adverbs with ‘e’. And guess what! There’s even a message recorded in Esperanto as part of Voyager 1’s golden record.

Is it practical enough? Nah. Is it cool? Wholesome? Oh yeah! You bet! 😇 Bonan tagon!

There is an international list of all threatened biological species that keeps track of their extinction risks. It is called The International Union for Conservation of Nature’s Red List of Threatened Species (IUCN Red List). Enthusiasts and organisations from many countries help by submiting and assessing the data. There is also another list called the IUCN Green List that keeps track of all the protected areas in the world.

Learned helplessness is a psychological phenomenon where an animal, after repeated traumatic experiences, eventually stops making any attempts to act upon it.

Way back, behavioural psychologists experimented on dogs by putting them in a cage where one half of the floor can be shocked. One group of dogs had the option to jump over a small barrier to avoid the shock. Another group of dogs didn’t have that choice. They had to endure the shock as long as it lasted.

Over time, after repeated trials, when the first group of dogs was put in an escapable shock cage again, they escaped by jumping the barrier — just how they were conditioned to. But the second group that had ‘learned’ to endure the shock refused to escape and took the shock passively, even when the escape was as easy as jumping the barrier.

Similarly, when humans are exposed to repeated negative emotions without escape, we eventually learn the ‘helpless’ state and continue to endure it even when we are capable of acting upon it or realising that we have control over the situation.

For the dogs, the learned helplessness was alleviated by training them to take the steps towards the escape. And in humans, just the realisation of the fact that we have control makes a huge difference. This is a widely considered area of research in product design as well.

Photo, music and video archival are fairly safe to be in digital formats for short time storage, but surprisingly not for long time archival. Today I learned that normal storage devices are susceptible to data degradation much like the old cassettes and tapes.

As flash storage devices store data as electrical charges, they gradually leak away and lose their state unless powered on often. Their approximate retention age is five years. They are not suited for long time archival. Magnetic disks pose a similar vulnerability too. Just by flipping one bit, your data can be corrupted.

Conservative political theorists often contrast tradition with reason and its stability with conflict. This, however, is a misleading ideological use of the concept of tradition, says the contemporary Scottish philosopher Alasdair MacIntyre.

MacIntyre reconceptualises ‘tradition’ as a historically extended, socially embodied, continuous argument, which is in part about the goods that constitute that tradition. Here, goods are understood as the (often trans-generational) pursuit of which gives the tradition its purpose and point. For a tradition to continue living, the virtues relevant to the pursuit of the goods need to be exercised.

Today I learned that typing cmd in the windows file explorer address bar will spawn a command prompt with the path set to the current open directory. Instead of navigating from a different directory or using Shift + Right click this is quick!

Inflation refers to an increase in the level of prices of goods and services in an economy. When the supply of money goes up faster than the real output of the economy, then it will generally increase the level of prices.

Inflation can also be caused by supply shocks. When the supply of a particular product becomes scarce, its demand will increase and its price will go up.

Scenario 1: When a government prints more money, banks will start lending more money, this will increase the amount of cash circulating in the economy. When people have more money in hand, their buying power will increase. Consumers are able to demand more goods than they normally do, but companies will still have the same amount of goods. Companies will respond by increasing the prices of their goods and services.

When inflation is too high, especially in a hyperinflated economy, people will stop using their currency altogether. Instead, people will swap goods for other goods or ask to be paid in other currencies like dollars, euros, etc. That’s what happened in Venezuela, Zimbabwe, and other countries that were hit by hyperinflation.

To keep the inflation in check, the money supply must increase at the same rate as real output of the economy, then prices will stay the same.

Scenario 2: An increase in oil price increases the cost of transporting a product from production to your nearest retail outlet. This will increase the price of that chocolate you regularly buy from the grocery store.

Saturn’s rings are new…relative to sharks. Sharks existed on Earth long before Saturn got its rings. Just learned this over a conversation and couldn’t help but wonder how many things we assume to be old but in reality, they are not that old.

“The findings indicate that Saturn’s rings formed between 10 million and 100 million years ago. From our planet’s perspective, that means Saturn’s rings may have formed during the age of dinosaurs.” - Source.

If you have to choose between being right and being kind, choose “kind”.

A machine, mechanical, digital, or biological, that is gifted to enchant the beholder into its operational design, is almost always the battle prize of an engineer falling for its enticements, in love, with its chain of enigmas, absorbing its caprices, and embracing its war cry to its life’s zenith.

What’s a timbre of a human voice? Let’s start with the voice! The human voice is created when vocal folds vibrate. It’s this vibration of air molecules when travelling through different cavities like pharynx, sinuses, nose, and mouth, that’s converted to speech. And here is the interesting part that makes them unique to a person.

Like any physical objects, these cavities through which the sound travels have their own properties as well. They have their own distinct natural frequencies because of the geometries of the muscles that are unique to a person and the composition of the air.

And the sound from the vocal folds is made of not just a uniform sine wave with a fundamental frequency, but a composite of other distinct frequencies as well. So when certain frequencies of that sound wave hit the natural frequencies of the cavities, resonance happens, and those parts alone get amplified. The end result of all this is the distinct voice of a person. In other words, the lowest resonant frequency that’s modulated by the rest of the frequencies is what gives that unique tone to your voice. And that’s what we call the ‘timbre’ of the voice.

The voice you hear when you inhale helium, that’s because of the timbre change too. Not the frequency shift!

Starry nights with clear skies are usually colder than a cloudy night. Ever noticed this? Why does it feel colder? Well, during the day, the sun heats up the Earth. But at night the heat is radiated back into the space. But when clouds are present, they act like an insulator and retain the radiated heat that would rather escape into the space without them in the way.

Temperature is not the measure of the heat. Most people think that they are the same. Take a pair of small and large vessels with water and expose it to the sun. You will find the smaller vessel becoming warm quicker than the larger one. Although an equal quantity of heat is supplied to the two vessels, due to the difference in the quantity of the water, the time it takes to raise the temperature varies. This must clarify the confusion between temperature and heat.

Are you pressing the up arrow key or doing history|grep in a Linux terminal to get that long command you typed last week? Don’t do that. Use Ctrl + R to do a reverse search and it will show the matching command with an autocomplete. It’s efficient. You can also cycle through the search results by pressing Ctrl + R again.

Collision cascading in space (Kessler syndrome) is what happens if the density of the space debris in the low earth orbit is high enough that one mishap could start a domino effect and cause more debris, eventually causing the rest of the satellites to collide with each other.

Ultimately, the additional debris from the collisions orbit the earth and render any future space expeditions impossible. Here’s a recent model of the current space debris status.

In any real-world dataset, the probability of the first digit of a value being 1 is very high compared to the rest of the values, with the digit 9 having the lowest probability. This interesting occurrence is well-known as Benford’s law.

$$P(d)=\log_{10}(d+1)-\log_{10}(d)$$

The intuition behind this observation is that a value in a real-world dataset spends a long time with its first digit as 1, and then the time shortens for every digit towards the digit 9 where it is the shortest. For example, if a value has to grow from 100 to 200, it needs to double itself. But when it reaches 900, the transition to 1000 is very quick as it’s just a 11% growth compared to 100 to 200, which is a 100% growth.

In other words, growth tends to be slow at the beginning (the first digit being 1) and exponentially faster as it reaches towards 9.

Just found that you can hold Alt and highlight the text of a link without worrying about accidentally clicking the link or selecting everything on the page.

Earth’s atmosphere is leaking a few grams of helium this very moment! Yep! As helium and hydrogen are the lightest elements of all, Earth’s gravity has little effect on them in the hydrostatic equilibrium. With higher kinetic energies, hydrogen and helium reach velocities greater than that of Earth’s escape velocity in the thermosphere and they shoot into space.

If you are developing a website you are likely using &nbsp; in your HTML for spacing characters. Just learned that it actually stands for ‘Non-breaking space’. In addition to this, there are &sp;, &thinsp;, &emsp;, &ensp;. Why didn’t I know these when I started? :/

A red herring prospectus is a document/booklet submitted by a company with the Securities and Exchange Commission (SEC), usually regarding the company’s initial public offering (IPO). The name “red herring” comes from the bold disclaimer in red on the cover page of the prospectus.

The red herring prospectus provides information that is useful for potential investors. It contains information about the company’s operations, the purpose of this share sale/issue, net proceeds to the issuing company, company’s balance sheet, earnings statement for the last 3 years, information about the company’s directors, and major shareholders, etc.

The spacebar in your smartphone (both Android and iOS) actually can help you move the cursor left and right. Touch the spacebar and slide it to the left or right while typing to move the cursor. Found this one by accident and it has now changed the way I type! 🤯

You all know what a circadian rhythm is! Biological functions like sleep and wake that are synchronised to the rotation of the earth over a period of approximately 24 hours. And you would also know that there are activities that cycle at a period longer than 24 hours — like menstruation in humans, migration and hibernation in animals. And of course, activities with shorter periods like hunger.

But do you know what these cycles are called? Just learned about the exact terms and they are super cool to say out loud!

Cycles that have a shorter period than the circadian rhythms are called ultradian rhythms. The ones that have a longer period, say like annually, are called infradian rhythms.

When it is really hard to name your character in your story, skip to the end credits of a film. There is no other place you can find a diverse list of real names.

Most of our older memories are partially distorted and has fake details in it. This is a very common occurrence as recalling or ‘remembering’ something is technically a reconstruction of events you learned and encoded into your memory ages ago. Between learning that memory and you recalling it now, you would have learned a lot of new and similar information. And these new encodings in your brain interferes with the old memories and affects the way how you recall them back.

In other words, new memories often interfere with old memories. Remembering is a very complicated process and most of the old stuff what you remember now is likely filled with made-up details. Biased, fabricated, and prone to errors.

If you frequently use Notepad to jot down things, use F5 to get the current timestamp. And even better, to automatically generate a timestamp whenever you open the file, add .LOG to the top of the file.

Private Self-Consciousness is the tendency to think about and attend to the more covert, hidden aspects of the self—aspects that are personal in nature and not accessible to the scrutiny of others. For example, one’s privately held beliefs, aspirations, feelings, and values. 💭

Private Self-Consciousness can be assessed with psychometric tools such as the Original Self-Consciousness Scale (Fenigstein, Scheier & Buss 1975) and the Revised Self-Consciousness Scale (Scheier & Carver 1985). 📝