Tag: scale

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

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The Coastline Paradox

By Anupum Pant

The length of Australia’s coastline according to two different sources is as follows:

  1. Year Book of Australia (1978) – 36,735 km
  2. Australian Handbook – 19,320 km

There is a significant difference in the numbers. In fact, one is almost double the other. So, what is really happening here? Which one is the correct data?
Actually, it depends. The correct data can be anyone of them or none of them. It completely depends on the kind of precision you decide to use while measuring the coastline. This is the coastline paradox.

The coastline paradox

The coastline paradox is the counter-intuitive observation that the coastline of a landmass does not have a well-defined length. – Wikipedia

The length of the coastline depends, in simple terms, on the length of scale you use to measure. For example, if you use a scale that is several kilometers long, you will get a total length which is much less than what you’d get when you would use a smaller scale. The longer scale, as explained neatly in this picture, will skip the details of the coastline.

This is exactly what happened when the two different sources measured the coastline of Australia. The first, Year Book of Ausralia, used a much longer scale than the one, Australian Handbook used. Ultimately, the great disparity in the result had to do with the precision of measurement. Had they used a scale just 1 mm in length, the result would have been a whooping 132,000 km.

This effect is similar to the mathematical fractal, Koch’s flake. Koch’s snowflake is a figure with finite area but infinite perimeter. Veritasium explains it better in this video:

Another factor is to take into account the estuaries to measure the length. Then,what about those little islands near the coast? and the little rocks that protrude out of the water surface? Which ones do you include to come out with the data?  And the majestic Bunda cliffs? Probably this article from the 1970’s clarifies what was included and what was not during the time the results were published.

So, the next time someone decides to test your general knowledge and asks you the length of certain country’s coastline, your answer should be – “It depends.”

How Loud Can it Get?

by Anupum Pant

Wives and moms can scream really well. But is it loud enough to inflict physical pain? Can sounds get louder than a nuclear bomb? How much damage can a loud sound cause? How about mass extinction? Read on to find out the answers.

What is sound?

Sound, as most of us know is a longitudinal, mechanical wave. That means, it is just a series of pressure changes [compressions and rarefactions] in a particular medium. So, the property of sound is as good as the medium it uses to travel. For instance, sound cannot travel in a vacuum due to the absence of any medium, but it can travel much faster in solids than in air. That is the reason you can’t hear someone talking in space (yes, movies that show loud explosions in space, lie). Also, the faster speed of sound in steel rails is exactly the reason why, you can tell a train is approaching, if you stick your ears to the rails (do not try this on electric rails).

Two of the fundamental parameters that describe a sound wave in numbers are pitch and amplitude. Pitch is measured in hertz – we’ll talk about it some other day. But, the amplitude of a sound wave determines how powerful it is; greater the amplitude, louder the sound. The loudness of sound is measured in Decibels (abbreviated dB).

More about decibel scale

Like most other linear scales, Decibel isn’t as easy to understand. A 10 point rise in the dB scale can be visualized as a 10 times increase in the loudness. Adding dB levels of different sound sources also doesn’t really work, the calculation is much more complicated; the resultant loudness depends on the coherency of the source [See this decibel addition applet]. Also, the perceived loudness is obviously lesser as you go away from the sound. Normally, a decibel scale ranging from 0 dB to 130 dB is enough for measuring the loudness of most things. But, things can get louder…much louder.

To get an idea of the decibel scale: 10 dB is 10 times more powerful than 0 dB, not 10 points greater. Similarly, 20 dB is 100 times more powerful and 140 dB is 100,000,000,000,000 times more powerful than a o dB sound.

0 dB is the loudness of near silence (a mosquito 10 feet away), while 120 dB is the loudness of a loud car horn heard from 1 meter away. Humans can hear sounds starting from 0 dB. But it can be quieter than 0 dB [the world’s quietest room]. It measures record setting -9 dB and can literally drive you crazy. In fact, the longest someone stayed in that room was for 45 minutes.
On the upper side of dB spectrum, a whisper is around 15 dB, conversations range from 40 – 60 dB and a jet engine measures 130 dB on the decibel scale. Like I said before, the perceived loudness depends on your ear’s distance from the source, so the loudness of a lawnmower can range anything from 90 dB to as much as 110 dB if you stand 3 feet away from it. [see the Decibel chart]

90 Decibels or a sound as loud as only a raised voice can cause gradual hearing loss (Refer to the hearing safety chart here). While 140 dB can cause physical pain. After 150 dB (firecracker) sounds can be felt in the form of shock waves. The pressure difference they cause in the medium can actually be felt by your body.

Beyond Decibels

Since the loudness depends on the medium, the maximum loudness a medium can propagate is dependent on its density. Our atmosphere can do nothing more than 190 dB, that, by the way, is enough to make you deaf or cause death. Sounds in water can get louder. A pistol shrimp is able to create a 200+ dB sound at 97 km/h to stun or kill its prey by snapping claws really fast. This is a very short lived pulse which doesn’t carry enough energy to do us any harm.

For events like the Saturn V launch, volcanic explosion, nuclear bomb explosion, earthquakes, star-quakes the concept of sound doesn’t really apply anymore. They are measured in terms of the shock wave they produce using the Richter scale. On this scale, 9 means total destruction (8.2 was measured during the explosion of the largest bomb ever, Tsar Bomba). An earthquake or earthly event measuring 10 has never been observed.

However, in the universe beyond earth, the starquake on the magnetar SGR 1806-20 registered 22.8 to 32 on the Richter scale. The magnetar released more energy in one-tenth of a second than our sun has released in 100,000 years. An event which thankfully took place 50,000 light-years away from earth. Had it been even 10 light-years away, the energy released would have wiped off life on earth. [read this BBC article for more information on this event]