Category: Physics

Helium Balloon in a Car

By Anupum Pant

Background

Whenever I choose to write about Helium, there’s something I almost never forget to mention – Helium is precious (Click to know why). So, if you’ve read that, you’ll know that you shouldn’t use it in party balloons, nor should you use it to make your voice sound funny. These are the most silliest things you could do with a borderline non-renewable resource. However, if someone uses it in party balloons to make science look cool to 5-year-old, it’s beautiful.

The Experiment

Destin, a super-cool dad, from the YouTube channel Smarter every day, did exactly that. This is what he did:

Pendulum in a car: First, he tied a pendulum to the roof of his car. Then he accelerated the car. As everyone must have guessed, the pendulum moved back as the car accelerated. It’s natural for our brains to assume that everything would move back in an accelerating vehicle.

Helium Balloon in a car: Next, he tied a balloon filled with Helium to the base of the car. Then, right when he was about to accelerate his car, he asked his 5 year olds sitting in the back seat – “Where do you think the balloon would go if I accelerate?”

Answer the question before proceeding, and reason it if you can. (Even if you don’t know it, it’s easier to guess it right now because of the build up I gave in the previous paragraphs)

The Answer

Unless you already have dealt with this “anomaly”, it’s pretty tough to guess that the balloon would actually move forward as the car accelerates. Yes, it moves forward! Something moving forward in an accelerating car sounds counter intuitive. I knew it because someone had asked me it in a physics puzzle sometime back. Just for the record, I had answered it wrong then. There’s no way I could have guessed, or reasoned it accurately the first time. Did you?

The balloon seems to be defying the laws of physics. But a helium balloon moving forward as the car accelerates can be completely explained by physics. It’s just our brain fooling us again.

Simple Analogy

Here’s how Destin explains it with a simple analogy – using a glass jar filled incompletely with water (so there’s an air bubble inside). Assume that the glass jar is like the car. The water in it, is like the air in the car. And the Helium balloon is like the air bubble in the jar – Since an air bubble is lighter than water, it is safe to assume that because even Helium is lighter than the air.

Now when the jar accelerates forward, the water in the jar moves back – so does the air in the car. As a result, the air in the jar moves forward – just like the Helium balloon does.

Here, watch the video if that sounds too confusing…

Most of you probably know this. But I’m sure that many don’t. Moreover I found the video really cute – A super cool dad explaining science to his little kids in a car. Plus they ask you to go to their audible link that would get you a free audio book. At the same time, it would help a cool dad fund his children’s education. My heart melted. If nothing, the video will at least make you smile.

The Hard Boiled Egg Sprinkler Mystery

By Anupum Pant

Background

Cracking an egg to check if it is boiled or not is not a very intelligent way. While many know that spinning an egg can be used to determine whether an egg is a boiled one or not, I’m amazed by the sheer number of people who aren’t still aware of this trick.

Just in case you are one of those who don’t know this, it works like this –  try spinning an egg on a smooth surface. If it spins well and stands up vertically, it is a boiled egg. If it doesn’t spin properly, you can say that it isn’t cooked….as simple as that.

Tip: There’s a way to check if your eggs have gone bad without risking opening it up to take in the nasty stench. [Here]

Boiled Egg Sprinkler Experiment

Now that I’m sure you know about the boiled egg spinning trick I can tell you about this simple experiment you can do at home. Besides dealing with an angry mom, it carries no other risks.

Here’s what you do – Get some milk and pour it on the kitchen counter. Now, boil an egg if you don’t have a boiled one already. Make sure it is hard-boiled by doing the spinning test. Next, spin it on the milk puddle you created on the counter. Nasty mess ensues…

Yes, there sure is a mess afterwards. But something amazing happens when the egg spins on the milk puddle. When it spins, the egg first stands up and then the milk starts rising on the surface of the egg till it reaches the equator and then the milk gets sprinkled at the equator in a very beautiful manner. It’s like a skirt of milk. Different sprinkling effects can be obtained with different spinning speeds.

Until now, no one knew why this happened. The rotating egg would suck up milk like magic and create a fountain of milk. The exact physics part of it wasn’t known until some researchers at Brigham Young University decided to figure out why this happens. I, on the other hand didn’t even know this sprinkling thing could be done. Nice to know.

Turns out, there’s nothing peculiar about milk and eggs that creates this effect. The same thing can be done with an 8-ball or any other ball for that matter. On the other side, it works with other liquids too. For instance, if you use a liquid with a higher viscosity (glycerine and water mix), the rotating ball could create not just sprinkles, but whole sheets of liquid getting flicked off at the equator. Some times if the fluid is viscous enough and the ball is spinning fast enough, sheets spanning several feet can be seen getting flicked off the equator of the spinning balls! It’s like a motor.

Here is an amazing hi-speed video of this happening in the laboratory and the elegant physics behind has been explained too. Watch it here:

After having watched the explanation, I can say one thing for sure: There’d be no sprinkling if this was done on Superfluid Helium because superfluid helium would have no viscosity and it wouldn’t rotate with the ball!

Weight of the Copper Tube with a Falling Magnet

By Anupum Pant

Remember I talked about Copper tube and a magnet a couple of days back? Turns out the same happens when you use an aluminium tube too. In short, a magnet (a strong one – neodymium magnet) when dropped into an aluminium or copper pipe falls very slowly, as if gravity stops acting on it.

It is due to the opposing magnetic forces generated by the electric field which is in turn generated by the magnetic field of the magnet (more in the link above).

That said, have you wondered what happens to the weight of the tube when the magnet is falling? Does it increase, decrease or remain the same? Just give it a guess and watch the following video.

The Royal Institution Explains:

Hit like if you learnt something today.

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.

Everyone Knows Magnet in a Copper Tube, But this…

By Anupum Pant

I’m sure you know that if you let a strong magnet drop along a thick copper tube, the magnet falls in a very interesting manner. It falls slower than it normally should, delaying the span of the fall, as if gravity acting on the magnet mysteriously drops. If you haven’t heard about it, I’ll give it to you, you probably aren’t a YouTube addict, and that’s definitely good (and maybe also bad because there’s awesome stuff out there which you are missing). Just watch this, what I just said will start making sense…

Why does this happen?

OK, that’s pretty cool, but you knew about this little magnet-copper trick already, and you were expecting something more? You got it.

Whatever you just saw neither was a magic trick, nor was the Copper tube acting as an anti-gravity machine. This is pure science, can be easily explained by it. Here…

When a magnet moves quickly near a metal, it generates current in the metal. Here, current is generated in the Copper tube.
The current generated in the tube generates another magnetic field which opposes the magnetic field of the magnet and pushes the magnet upwards, away from the force of gravity. Gravity being stronger, pulls it down, but not with as much force because the magnet is being pushed in the other direction too. That’s the simple science behind it.
Still, someone else could explain it better on a page which is completely dedicated to explain it to you. [Here] and [Here]

But, you probably knew even that -The trick and the science behind it. So, there’s more for your-kind-of-people.

A new skill-toy that uses the same…

Feel flux. An amazing new skill toy that works on the same principle. Who would have thought, playing with gravity could get fun. The crowd funding campaign for it runs on indiegogo. Go fund it!

Watch How 32 Metronomes get Synchronized Automatically!

By Anupum Pant

Background

From biological cells to celestial bodies spontaneous synchronisation is found everywhere in the nature. In simple words, you could call “spontaneous synchronisation” as “a natural self-organisational behaviour” in things. Where, out of a chaos, uniform order starts appearing. If that feels too abstract to understand, read on…

Probably the first human to note this effect was a Dutch physicist, Huygens. Huygens noticed this when he was working on a ship with two pendulum clocks. For very long times, his work of calculating longitudes required him to watch these clocks swinging away their pendulums. He would lie on the bed and watch them go. There was one weird thing he noticed about these pendulum clocks. No matter how the pendulums started swinging, after an hour or so, both the pendulums ended up synchronized! This was a perfect example of uniform order appearing out of no where from an apparent chaos.

The effect amazed scientists for about 350 years. Only then some researchers at Georgia Tech University, were they able to produce a perfect mathematical model that proved it. So, what was happening on the boat? In a similar fashion, would all pendulum clocks in the world get spontaneously synchronized? Let’s look at the following example to find the answer.

Synchronizing metronomes

Think of it this way. You have a couple of metronomes with you – the physical ones, the ones that are based on pendulums. You start each one of them and there is almost no chance that you’d get them perfectly synchronized in the first go. So what do you do to get them synced?

You simply keep all of these metronomes (ticking with the same frequency but different phase relations) on a free-floating table. That gets them synchronized in a matter of minutes. See how the 32 metronomes completely out of sync of each other get synchronized in the following video. Note that they are on a surface that is free-floating.

Adam Milkovich explains the effect very beautifully in the following video:

Another video – Link

Back to Huygens

Now, if we come to see the boat as a free-floating base and the 2 discordant pendulum clocks as metronomes, the segue of their motion into a perfectly synchronized one, makes complete sense.

The only difference is that the boat was a pretty huge free-floating base – something which has a relatively very high mass as compared to the pendulums. And then there is the drag on water; other forces etc.. The pendulums had a very very tiny effect on the boat and in turn, were able to transfer only a teeny bit of energy with every oscillation. So it took longer.

I find it pretty incredible that it even happened in an hour. I think it would have taken a much longer time, given the huge difference in their masses. May be Huygens exaggerated. Or it was a very small boat. Anyway, that is the reason, Huygens’ clocks took about an hour to get synchronized. While the ones we see above are able to do it in a matter of minutes.

Back to the Question

Would all pendulum clocks in the world would get spontaneously synchronized?

Well, I’m not too sure. But this is how I see it:

I think of Earth as a really really really huge free-floating boat. Now, the movement of pendulums on Earth certainly has an effect on the earth. And in turn the other pendulums get affected. And they end up synchronized at some point. But the first effect itself is unimaginably small.

I mean, the Earth is so massive that even if all of the 7 billion people on Earth jumped at the same time, the 6-trillion-trillion-kilogram Earth would move so less. Earth would move about a hundredth of the radius of a single hydrogen atom.

So, pendulums would hardly have any effect. But the effect would certainly be there.

Therefore, I’d say the answer is yes. Yes, all the pendulum clocks on earth would eventually get synchronized. But it would probably take so long, that even earth, leave alone pendulum clocks, would cease existing.

Toy idea: Well, that gives me a great idea for a toy. 5 – 10 pendulums inside a huge pendulum. The inner ones would get beautifully synchronized automatically!

Hit like if you learnt something today.

5 Visually Incredible Science Experiments You Cannot Miss

By Anupum Pant

Here is a small list of visually incredible science experiments that will keep you visually mesmerized for a couple of minutes. Later, you’ll be left wondering about what you just saw.

The list is a small one, to not overwhelm those avid readers who follow the articles everyday. I think, more than 5 videos, is just too much wonder to take for a single day.
I do have a collection of hundreds of other such incredible experiment videos (in my bookmarks) that I’ll be sharing in the future…probably with the same heading suffixed with “part 2”.

Now without any more delay, here is the list. Have fun and do share if you like them! Ask me in the comments section if you have any questions.

1. Decomposition of Mercury (II) Thiocyanate

2. Liquid Nitrogen + 1500 Ping Pong balls

3. Dry Ice + Water

4. Quantum Trapping / Quantum Locking

5. Flying top

Can a Single Sand Grain Power a Car for 10 km?

By Anupum Pant

I literally binge on YouTube, especially on science videos. Since I’ve been doing it for a long time, I follow a huge number of channels and among them, are some channels that need a special mention. For that, my plan for today was to create a list of five to ten spectacular YouTube science channels that are not popularly known. But while carrying out the research to collect data for this little list, I happened to stumble upon something which needs a post dedicated to it. So, I thought of delaying my original plan of collating a list of those lesser known science channels.

Background

To tell you about the thing I discovered, you need to know this first:

MinutePhysics: You know MinutePhysics right? I mean, who doesn’t know them. If you think you’ve never come across a video of their’s, try going to their channel. There is a high chance you’ll recognize their signature style of simplifying science – through animated videos. With more than 2 Million fans on YouTube, they have a huge following and almost every video of their’s goes viral, to some extent. It was started by Henry Reich and I’m guessing there is definitely a team behind the channel – If some one from MinutePhysics is reading this, like the one I did with Jaan Altosaar from UsefulScience.org, I’d love to do a short chat with you, if you have the time.

MinuteEarth: Now, the same people who created MinutePhysics also upload similar styled videos explaining the planet earth at MinuteEarth. You should check that out too. But that is not all I’m talking today…

MinuteLabs

I’m not sure how I landed on the Youtube page of MinuteLabs.io, but the instant I spotted the dot io in the end, I knew there was more to this channel than just two videos. I watched one of those videos – video (embedded below)

I could instantly connect to what Jasper was doing in the video. I often have such questions and I make these queries on Google all the time. But I had never endeavored to do what he (maybe with his team) did on his website.  And that brought me to MinuteLabs.io‘s Mass-energy scale.

Mass-Energy scale

When you land on the Mass-Energy scale page of MinuteLabs, you’ll find a vertically massive scale, listing out a couple of things on the right and left side. So, this is a scale which is based on the popular equation E=MC2 .

It lists out a number of everyday (plus other) objects and the energy associated with them on the left side. On the right side of this scale are the masses of some other objects. This is how it works…

minutelabs mass energy scale

For example, if you take the mass of a sand-grain and multiply it with the constant C2, you’ll end up with some amount of energy (E) that is *theoretically* stored in its mass. To get an idea about how much this energy is, they have collected that huge list of energies associated with everyday objects on the left scale.

After referring to the scale, you’ll find that the amount of energy that is theoretically stored in the mass of a sand grain is almost equal to the energy that is needed to move a family car by 10 km. Even though you don’t really have an access to all that energy, Isn’t that huge, for a “very fine sand grain”! Check out the scale to see how huge things can get…

What I appreciate about it

Firstly, I appreciate the amount of effort it would have taken to collect that sort of data. I know that because I’ve tried doing something similar once. Trust me, It is a pain!

Secondly, I appreciate the fact (and again the effort) that their media is made using the latest web technologies. This makes their media so accessible to people.  Today, all you need for learning science, is an internet connection and a nice browser, like Chrome or Safari.

Besides this particular media (Mass-Energy scale) they have created, there are a couple of others that have already been up and running since the start of this year. I’m sure, like me, you’ll have a couple of hours of fun, learning and playing around with them. Cheers to simplified science and MinuteLabs for doing this project.

A Request

If you liked the post, I ask you for just two things – subscribe from the right side bar and like my Facebook page for updates like these. That’ll be a big help!

Michio Kaku’s High-School Science Fair Project was Astounding

By Anupum Pant

michiokakuDr. Michio Kaku without a doubt is one of the finest Physicist of the present times. Besides that he is also a very popular person. If you watch TV, you must have definitely seen this man some where. He has made several appearances on TV channels like  BBC, the Discovery Channel, the History Channel, and the Science Channel. Also, he has written books and hosts a radio show.
He has made science popular. But if you live in a cave, this person in the picture is the man I’m talking about.

What made him the man he is today, was his great love for science since childhood. By the time he was in high-school, he had started doing incredible things. His high-school science fair project story, pretty much sums up the remarkable things he had started doing back then.

The science fair project

During his high school, when he was working on anti-matter photography, he had an idea to create his own anti-matter beam. He then went to his mom and asked her this:

Mom, can I have permission to build a 2.3 million volt atom smasher betatronic accelerator in my garage?

The shocked and proud mom obviously agreed to the proposal. This is what he had to procure to convert his idea into a reality:

  • 400 pounds of transformer steel
  • 22 miles! of copper wire

With the help of his parents, he wound the 22 mile long copper wire around a football field that was able to generate a magnetic field 20,000 times greater than the Earth’s magnetic field. It could produce collisions powerful enough to create antimatter. After a few troubles with the power, there, he had his own  2.3 eV atom smasher (cyclic particle accelerator).

This was an atom smasher built in his backyard garage – a mini version of the $ 10 Billion Large Hadron Collider.

Changed his life

This science fair put him in the right track. A nuclear scientist, Edward Teller, noticed it in the National Science Fair and spread the word to the scientific community. And soon, he got a full ride to the Harvard University.

via FromQuarkstoQuasars

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Einstein Couldn’t Figure How the Drinking Bird Worked

By Anupum Pant

Background

DrinkingBirdThe Drinking Bird is a toy which almost every one of us has heard of. If you haven’t, may be this picture of it rings a bell. Otherwise, it is a funny looking bird-head made of felt, mounted atop a glass or plastic straw, with a little bulb at its lowest point. The whole contraption is suspended at two points, which allows it to swing smoothly like a pendulum – drinking water at regular intervals, from a glass, for ever.

The amusing thing about this little toy is that, once it starts, it keeps swinging and “drinking” for ever. Upon giving it a cursory look, it seems to be a perfect perpetual machine – a contraption that can run indefinitely without an external source of energy. In reality, it isn’t a perpetual motion machine. There is a complex physical and chemical activity going on inside the toy, which keeps the simple heat engine running forever without a battery – Something so complex to deduct, that even one of the greatest Physicist ever, Albert Einstein himself couldn’t figure out the correct mechanism that keeps it running.

Don’t worry, it isn’t as difficult to understand the mechanism.

How does it work?

Assuming you have properly understood the parts of the toy, you will notice that the little bulb at the bottom of it has a colored liquid in it. This colored liquid is a chemical called Methylene chloride – A chemical that dissolves caffeine and can be used to decaffeinate coffee, teas and colas. The special property of this chemical which makes the toy work is its extremely low boiling point. It has a high vapor pressure at room temperature.

At room temperature the vapor pressure in the tube and head is high. The fluid remains in the bulb and the bird is upright due to the weight of the fluid.

The first thing you do is, you make its head dip in water. That way, the head made of felt absorbs water. The water cools due to evaporation (like our sweat cools our body), drops the temperature of the head and the bird comes up.

While swinging in the upright position, as the head cools further, the vapor pressure at the head decreases, while the pressure at the bulb becomes relatively higher. This causes the chemical to rise up the tube and it changes the center of gravity (CG). Due to the change in CG the bird tips its head back into the water.

Absorbs water and the process starts once again. It keeps on going till the bird can no longer reach the low water level. You, then have to fill up the reservoir.

Source of energy?

There is a lot going on in the toy so it isn’t really easy to point a single source of energy. However, it is pretty clear that the bird isn’t a perpetual motion machine. Anyway, watch the insightful video now. The simple toy is indeed a beautiful thing to marvel about. [Video]

The Domino Effect Physics Can be Pretty Incredible

By Anupum Pant

falling dominoesDomino effect is a fairly well-known mechanical effect in which a single falling domino (A tile of the tile-based game called Dominoes) causes a chain reaction. The resulting chain reaction depends on the size of arrangement – number of arranged dominoes.

Usually  hundred to hundred thousand equal sized dominoes are carefully arranged to form a sequence. Then, the first domino is flicked to start a huge chain reaction. There have been several world records with kinds of falling-domino-patterns based on this effect. But there is one thing about the domino effect that isn’t popularly known.

The 2X rule

When these falling domino records are made, they are usually done with equal sized dominoes. Suppose, continuously increasing sized dominoes are used in sequence, the size of falling dominoes can go really huge, pretty fast.

The limit: When the size of second domino is from 1.5 to 2 times the size ( says a physics study) of the first domino, it can fall with ease. But that is the limit. If the second domino is any larger than 2 times the size of the previous domino, it won’t fall down – stopping the chain reaction in between. So, 1.5 times the size of the previous domino is a pretty safe increment to use, if you really want your chain reaction to complete.

So, Morris in the video below, uses the first domino which is 5mm high and 1mm thick (I’m wondering how he manages to balance it on the 1mm side). The domino placed next to it is, 1.5 times thicker, longer and wider. So, if it is made of the same material, the second one would weigh more than 3.3 times the weight of the first one. Now do the math.

He uses 13 dominoes with increasing sizes. The last one is about a meter tall and weighs about 50 kg. Remember, the first one probably weighed no more than a few grams.

He flicks the 5 mm domino and within a second or two, due to the chain reaction, the largest one that weighs 50 kg, falls down with a huge bang. Had he used a few more dominoes and would have made the count to 29, the last one would have been as tall as the Empire State building. Imagine a domino of that size falling with such a measly initial energy expended to make the 5 mm sized domino fall.

The amplification of energy is about 2 Billion times! Thanks to the stored Gravitational energy.

Physics is marvelous. Isn’t it? [Video]

Yes, Light Can Push Physical Objects

By Anupum Pant

Tim is a 71-year-old eccentric who has been collecting interesting toys for 50 years now. Today he has a collection of around 250,000 absurd toys in suitcases, labeled and stacked in a room from the floor to the ceiling. He shows them off in a Youtube channel regularly. I almost never miss any of his toys. Usually most the toys he displays amaze you, but do not blow off your mind. The last one did.

Before this, I had not known that light can push or move a physical object. So, I decided to investigate a bit.

The Extraordinary Toy

In his last video, he showed off a beautiful glass bulb mounted on a wooden stand, that he says has been made by some German company. The bulb has a very good vacuüm (not complete vacuüm, just enough to not create unnecessary drag for the vanes) and encloses a fan-like structure that starts rotating when a bright light is switched on near it. Some people call it the light mill – like the wind mill moves with the wind, this one moves when photons hit it. If give enough time, the mill can accelerate to really good speeds (at thousands of rounds per minute). Watch the video below. [Video]

Theories on how a radiometer really works

The device, a special kind of radiometer, was invented around 140 years back in the year 1873, by Victorian experimenter Sir William Crookes to measure the radiant energy of heat or light. It has four vanes mounted at the edge of four stiff wires to make a fan, each of which has a black side and a silvered side. All of this is enclosed in a bulb which is evacuated enough to not cause drag due to air. In complete vacuüm the vanes move in an opposite direction, but that experiment is really difficult to recreate!

  1. When light is turned on, the fan moves in a way that makes it look as if light is pushing away the black colored side. The theory of photons pushing the black side was accepted initially. But soon a problem was seen with the theory. If light is absorbed at the blackened side and reflected at the silvered side, the fan should be moving in the opposite direction.
  2. Then came in the other explanation which explained that the heated black side due to absorbed radiation rarefied the air near the black side and hence caused the gas to rush in and push that side. The greater the heat, the more this back side would get pushed and it would spin faster. Later even this theory was proved to be wrong. But, Britannica, till date decides to go with this explanation – to some extent this theory goes in the right direction, you will see why…
  3. One more theory claimed that the heat evaporated the impurities on the black side, whose force made it spin.

How the radiometer really works?

The correct explanation was given by a  prominent Anglo-Irish innovator, Osbourne Reynolds. He explained it by mentioning a porous plate, where the air inside the holes would flow from the colder sides to the warmer side (obviously) and make the vanes spin in the opposite direction. He called it “Thermal Transpiration” – makes sense and is easy to understand. But the vanes here are not porous. So…

He said that “Thermal Transpiration” in the vanes takes place at the edge of the vanes and not the faces. Think of edges as small pores, he said.

Due to a temperature gradient formed, the air starts moving along the surface from colder to the warmer side through the edges. The net pressure difference around the vane is created which pushes it in a direction that is away from warmer air and towards the colder air – makes sense for the apparatus.

This is the reason, if it is cooled, it moves in the opposite direction.

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Train Wheels are Not as Simple as They Seem

By Anupum Pant

I’m pretty sure not many of you know this about train wheels, neither did I.

Look at the picture and answer this: What do you think keeps a train moving on the track? or Which part of the wheel do you think it is that keeps the train from careening away from the track at turns?
Applying general logic, I thought that flanges at the end of the wheels  kept a train from going off rails at a turn. Turns out, I was wrong!

In fact, flanges at the end of the wheels are just a safety mechanism to keep the train on its track only if the main mechanism fails. And what is that main mechanism?

The problem with cornersTrain wheels are conical in shape. That means they have a varying diameter at different points of contact. Now, suppose the track turns right. The train’s left wheels now have to travel more than the right wheels because at the turn the track on the left is longer.

So how do the left wheels travels more than the right wheels without a differential?
Since the wheels are conical in shape, the whole wheel-set shifts a bit to the left, if the track curves right. Now the point of contact of the left wheel is at a larger diameter of the cone. While the smaller wheel Correction from the toptouches at a point where the diameter of the wheel is lesser. Therefore, if the left wheel now makes one circle it travels further than the right wheels and the train moves along the curve smoothly.

The whole beauty of this system is that the amount of shift of the wheel-set happens automatically, makes the train move on turns smoothly and keeps the train on track.

Look at how you can try this at home using 2 plastic cups and 2 similar pipes. [Experiment]

If I couldn’t explain it properly, probably the best physics teacher ever – Richard Feynman – will explain it to you better. [Video]

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Snow Does Not Melt Like You Think It Would

By Anupum Pant

Background

For the last several days, the national average temperature in the US plunged by a several notches when the country was invaded by the bitingly cold polar vortex winds from the arctic, not once, twice. For the second time, the eastern sea board experienced a lot of trouble. So much that the state of Georgia, Alabama, Mississippi, Louisiana, North Carolina and South Carolina declared a state of emergency. People got trapped for hours, hundreds of accidents were reported and schools had to shut down.

Conspiracy theories

Of course with the extremely cold winds came an abnormal amount of snow. And like always, even the seemingly harmless snow spurred a few theorists to spin out conspiracy theories. There were stories going viral that suggested that the crazy amounts of snow was actually “geo-engineered” and was being sent down by the government, stuffed with nano-bots to control the minds of people.

What backed them? The theories were backed with a claim that the material falling down from the sky was not actually snow and something else which did not melt when held against a flame. Videos showing people trying to melt the snowballs using a cigarette lighter went viral. In fact, the snow as it’d be expected to, wasn’t melting, it was collapsing. Like a Styrofoam dipped in acetone, or Styrofoam held against a flame would do, snow was mysteriously disappearing from around the flame. There was no dripping water. Moreover, the concave part of the snow was left with a black charred mark like plastic would!

Busted!

Turns out the “mysterious material” was nothing more than normal snow. The lesser known fact that snow does not melt like we’d  expect it to, made people believe in the weird theories.

Yes, snow does not melt like normal ice. I mean it does melt, but it leaves almost no dripping water when the rate of melting is slow. Now, why is that?

Since, snow is porous, it contains several little holes that can suck in the water just like a tissue paper with tiny holes is able to soak in water. This particular process soaking, where tiny solid holes suck liquid, is termed as capillary action and is the same action which enables plants to suck in water from the ground and send it to the higher parts without any motor attached.

The soaking in a snowball happens in real-time. As the water gets melted, it gets soaked instantly, there is no time for the water to drip. This explains the collapsing snow.

The “charred snow” is due to the unburnt carbon left from the fuel of the lighter, not because it is made of plastic. Astronomer and science writer Phil Plait explains it in the video below. [Video]

via [PopSci]

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Gravity Defying Chain of Beads

By Anupum Pant

Chain of Beads

Suppose, you have a neat pile of a really long chain of beads in a beaker (Newton’s beads) and you give one end of the beads a tug and let it drop on the floor, what do you think will happen?

Steve Mould, a YouTuber, did the same with a 8000 bead chain. It was 50 meter long chain of beads placed neatly in a container. Then, after he tugged it out and let it drop, the chain mysteriously formed an arc above the beaker and continued to self-siphon away till the end. Just like a water-siphon.

Watch it in video to see what happens. [Video]

What keeps it going?

To figure out what was actually going on here and to understand the exact physics of it, a group of physicists recorded the “gravitational defiance” using a hi-speed camera. Here is a five-minute long video-bliss, brought to you by the Earth Unplugged channel. [video]

As Steve explains, it is like a tug-of war between the outer chain and the inner chain. The inner chain has to keep up with the fast-moving outer chain. As a result, it [the inner chain] goes up fast. It builds up momentum and is unable to stop itself. So, it ends up forming that arc while it is trying to slow down and change direction.