Popular shared stories on NewsBlur.
1044 stories
·
24373 followers

Ink Molecules

3 Comments and 7 Shares

Ink Molecules

Suppose you were to print, in 12 point text, the numeral 1 using a common cheap ink-jet printer. How many molecules of the ink would be used? At what numerical value would the number printed approximately equal the number of ink molecules used?

David Pelkey

This is the kind of problem where Fermi estimation comes in handy. In Fermi estimation, we're not concerned about exact numbers. We just want, before we start doing research, to get an idea of how big the number is going to be. Will it have 10 digits, or 100 digits, or a zillion?

We'll see what we can figure out before we look anything up.

An inkjet cartridge lets me print out some number of 8.5"x11" black-and-white pages. Let's be optimistic and say a few hundred. If each page has 500 words and each word has 5 letters, then each page has 2,500 letters. 100 pages is 250,000 letters and 400 would be 1,000,000. So the number of letters per cartridge probably has six digits.

Now, how many molecules are in an ink cartridge? This will be harder to estimate without cheating and looking things up, but let's try.

Let's say I remember hearing about "Avogadro's number" in chemistry class, but I don't remember exactly what it is. It's definitely something times 1023, so it has 24 digits. And I remember that it's the number of atoms in some number of grams of something. It was a smallish number. Probably.[1]For the record, it's 6.022×1023, and it's the number of carbon-12 atoms in 12 grams of carbon-12 (or the number of hydrogen atoms in a gram of hydrogen).

Inkjet cartriges probably also contain a small number of grams of ink.[2]Citation: If it were a big number, they would be hard to pick up, and if it were less than a gram, the idea that we've been paying $30 for them is just too upsetting to contemplate. Let's assume it's the same small number, because Fermi estimation lets us do that.

I have no idea what's in ink. (Remember, we're not allowed to look stuff up yet.) I know squid can make ink of some kind, so maybe ink has some big complicated organic molecules in it. That's bad, because I have no chance of estimating their weights to within even a few orders of magnitude.

Fortunately, what we need to worry the most about is the smallest molecules, because they'll contribute the most to the total count.

Ink probably has a lot of water in it, like many liquids. On the other hand, I bet most of those water molecules wander off when the ink dries—since that's what the word "dries" means.

We have nothing to go on here, so let's take a wild guess and suppose that a 10% of ink's bulk comes from large numbers of little molecules, ones comparable in size to the [mumble mumble carbon or something] atoms in Avogadro's number. Since Avogadro's number has 24 digits, 10% of it would be a 23-digit number. If our other guesses are right, then the number of molecules in an ink cartridge might also have about 23 digits

If there are a 23-digit number of molecules in an ink cartridge, and that cartridge prints a 6-digit number of letters, then each printed letter (or number) should contain a number of ink molecules with 23 - 6 = 17 digits.[3]What we're doing here is dividing by subtracting the number of digits. If you think this is a cool shortcut, and decide to develop it further and make it a little more rigorous and precise, then congratulations! You've just invented logarithms.

That means a printed 10-digit number contains about an 18-digit number of ink molecules, and a 100-digit number contains a 19-digit number of ink molecules. Aha! The crossover point, where the number of molecules and the printed number are equal, must happen somewhere between 18 and 19 digits.

So our answer, according to Fermi estimation, is in the neighborhood of a high 18-digit number. We might be off by several orders of magnitude in either direction, but in either case, it's definitely a number you could print out on a single line.

Now, let's do some actual research and find out how we did.

Inks, unsurprisingly, are complicated and vary a lot. Color inks contain a lot of large and heavy molecules, especially some of the pigments. Fortunately, cheap black inks—which are what David asked about—are simpler.

As our example, we'll take the ink used in the random HP printer at my house. HP doesn't disclose everything about what the ink is made of, but they do publish a material safety data sheet for it here.

The MSDS data tells us that the ink is over 70% water. It also contains the molecule 2-pyrrolidone (which is apparently used to synthesize the anti-seizure drug Ethosuximide) and 1,5-pentanediol.

In addition, it contains up to 5% "modified carbon black", a form of crystalline carbon (like graphite and diamond). This is great news for our estimate, because crystalline carbon is very simple; its molecular formula is just "C".[4]Assuming you count each carbon atom separately. You could interpret David's question to mean particles of ink, so each hunk of carbon black would only count as 1. However, that would mean working out exactly what water fraction remains in the dried ink and how much weight 1,5-pentanediol contributes and so forth, and that sounds like more work.

Conveniently, "C" is also what's used in the definition of Avogadro's number. Small consumer cartridges contain a few grams of ink, which is less than the 12 grams used in Avogadro's number. That might make our estimate about half a digit too high. And while we were lucky at guessing carbon, HP ink contains less than 5% carbon black, not the 10% we guessed. That pushes the real answer down even lower than our estimate. But all in all, we did pretty well!

Of course, this is a reminder of how much easier the digital world is:

It's also a reminder of how expensive ink is. Speaking of which, the ink sac from the tiny Octopoteuthis deletron squid are probably a few milliliters, based on the collection bottle sizes mentioned in this paper, for a squid that probably only weighs a hundred grams or so.

$30 could probably get you a few kilograms of fresh whole squid, and—if you picked the right squid—a total of five or six cartridges worth of ink.

Lifehacks.

Read the whole story
Share this story
Delete
3 public comments
kicking_kk
17 hours ago
reply
I just want a squid printer now.
rclatterbuck
17 hours ago
reply
More Fermi Estimation.
jepler
18 hours ago
reply
"Now, let's do some actual research and find out how we did."
Earth, Sol system, Western spiral arm

What's Better Than A Total Eclipse Of The Sun? Check This

2 Comments and 9 Shares

What's Better Than A Total Eclipse Of The Sun? Check This

Any eclipse is worth seeing. A total eclipse — where the moon completely blots out the sun, where day turns to night, where solar flares ring the moon's shadow like a crown of flame — that's the eclipse everybody wants to see, the alpha eclipse that eclipses all the other eclipses. Everybody knows this (me included), until I saw this ...

Solar eclipse or cross-eyed space alien?
Solar eclipse or cross-eyed space alien?
NASA/JPL-Caltech

Yes, it looks like a cross-eyed space alien staring out of the darkness, so to make things clearer, let me add one more "eye," like this ...

A set of three images showing the larger of Mars' two moons, Phobos, passed directly in front of the sun as seen by NASA's Mars rover Curiosity.
A set of three images showing the larger of Mars' two moons, Phobos, passed directly in front of the sun as seen by NASA's Mars rover Curiosity.
NASA/JPL-Caltech

What are we looking at? On Aug. August 20, 2013, NASA's robot Curiosity was sitting on a Martian plain and one of its cameras looked up at the sky and saw the little moon Phobos passing across the face of the sun. Curiosity's camera snapped a picture every three seconds. So what you see here is a sequence. The moon appears on the right side of the sun, moves center, exits left, a passage that took about 37 seconds. Had you been on Mars that day, this (NASA animated its photos) is what you would have seen ...

NASA Jet Propulsion Laboratory/YouTube

Obviously, this is not a total eclipse. Phobos, it turns out, is too small to cover the sun. It is, amazingly, only 14 miles wide. Our moon, by comparison, is 2,160 miles across.

So how does this itty bitty moon manage to loom so large against the sun, and how come it's so rock-like, so bumpy around the edges — so utterly gorgeous to watch?

The answer is, Phobos orbits very close to Mars' surface. It's only 3,700 miles up. Our moon, by contrast, is (on average) 239,000 miles away. So, Phobos is sailing very, very near, which is why Curiosity can see it in such detail and why it blots out so much of the sun.

Which Would I Rather See?

If you asked me to choose between a total solar eclipse of our moon, and a chance to catch Phobos voguing in sharp outline while I watch from a Martian plain, I'm going for the Martian option: the Little Guy in Partial Eclipse. Not only is it thrillingly beautiful, it is also, I should mention, a tragedy in motion.

Our moon, the Earth's moon, has been gradually drifting away from us. When the Earth earth was younger, our moon was 10 times closer than it is now. Phobos, on the other hand, isn't moving out, it's moving in — closer and closer and closer to Mars. What's more, it's slowing down.

These days it circles Mars every eight 8 hours. But in the next 10 to 15 million years or so, Mark Lemmon , of Texas A&M University University, told Space.com, Phobos will slow its speed so significantly that, at some point, it will "get so close that tidal forces from Mars will very likely break it up before it does start grazing the atmosphere and come down."

Oh, No ...

What happens then? When a moon disintegrates, it breaks into hundreds of millions of pieces; those pieces splay, then gather, and (at least for a while) they become a ring — like the rings we see around Saturn. When Phobos goes, "Mars may briefly have a ring system," says Lemmon.

'Goodbye,' The Little Moon Is Saying

Which is why, when you see Phobos in partial eclipse on Mars, you are watching a diva making what will one day be its final appearance in our solar system.

So consider what we've got here: a death spiral, a light show, a dying beauty backlit by the sun, What's more fantastic than that? Yes, total eclipses are still nice, still worth traveling to see, but now that I know what Mars gets to see, see — I'm switching sides. When it comes to eclipses, Partial is the new Total.

At least when I'm on Mars.


Thanks to Marc Kaufman, whose new book, Mars Up Close: Inside the Curiosity Mission, introduced me to some of the images featured here.

Copyright 2014 NPR. To see more, visit http://www.npr.org/.
Read the whole story
wreichard
1 day ago
reply
Sooooo cool.
Earth
Share this story
Delete
1 public comment
superiphi
1 day ago
reply
I'm with Phobos. I want to die on Mars
Idle, Bradford, United Kingdom

Reeder and NewsBlur, sitting in a tree...

9 Comments and 11 Shares

…S-Y-N-C-I-N-G.

First comes feeds, then comes training, then comes social for those days when its raining.

That’s not it! That’s not all! Runs on iOS and Mac, so have a ball!

The world’s most popular RSS feed reader now supports the world’s best RSS feed reader backend. Download Reeder 2 for Mac and iOS.

Read the whole story
wreichard
1 day ago
reply
Reeder can now use the Newsblur infrastructure!
Earth
samuel
1 day ago
reply
This is pretty exciting! Reeder has added NewsBlur support, and now I hope to see sharing and training. Sooooon.

Make sure you tell @reederapp on Twitter how you feel about fuller NewsBlur support. Every tweet helps.
The Haight in San Francisco
BLueSS
1 day ago
That was a fun post intro.
Share this story
Delete
5 public comments
jimwise
5 hours ago
reply
Ooooooooh.

Reeder was my google reader client of choice.

OTOH, I've gotten very used to the iOS NB app.

But I'll have to try this...
jimwise
4 hours ago
Okay, so the interface is even better than I remember, and it's blazingly fast compared to the NB app, but... But... No seeing comments. No friends' shares. No sharing. So not a replacement. Yet.
Mother Hydra
12 hours ago
reply
Comments and community are Newsblur's secret sauce. I could see myself loading this up only occasionally.
Beneath Innsmouth
samuel
10 hours ago
Yeah, personally I still prefer the NewsBlur app. I never used Reeder as I didn't care for its navigation. Hence why NewsBlur's iOS app works the way it does.
zelig2
17 hours ago
reply
Glad to hear but using Reeder or ReadKit both appear to loose the public comments that I can see directly on NewsBlur. I enjoy that social aspect of NewsBlur.
futurile
1 day ago
reply
Great news
London
kemayo
1 day ago
reply
Finally! I used reeder back before the end of google reader, and I've missed it.
St Louis, MO

Why You Should Not Take Photos Of The 7 Ugliest Buildings In D.C

2 Comments and 17 Shares

On July 16 and 17, I visited seven different government bureaucracies throughout Washington, D.C., so I could photograph how ugly their architecture was.

Are you ready for the secret behind how I did it? You sure you want to know?

I stood on the public sidewalks in front of the buildings, along with all the other tourists and pedestrians, took pictures, and then hopped on my bike and went to the next building.

I did not cross any police barriers, nor did I ever take any photos inside the buildings.

And while it is very obvious that you are being watched …

…there are definitely no signs prohibiting you from taking pictures of the massive, ugly buildings from the street.

I mean, from the street, right? Big tourist town, right?

That’s why I found it so odd that I was confronted by federal police, and often told to leave, at six of the seven stops.

This restrictive behavior is totally different from what many department and agency officials will tell you.

1. The Federal Bureau of Investigation:

On Thursday, a spokesperson for the FBI told BuzzFeed that you can take photos outside of the building, adding: “Tourists do it all the time.”

But when I tried to take this photo of a building entrance…

…police stopped me, telling me that “only photos of the front of the building” are allowed.

Then, I was approached by an armed bike cop who questioned further why I was taking photos.

The bike cop rode a few yards behind me while I walked the remaining circumference of the building. He stayed in this spot until I walked across the street and left.

2. The U.S. Post Office Building

A spokesperson for the U.S. Post Office did not return BuzzFeed’s calls for comment.

When I tried to take photos there…

…after taking the above photo of the public, ahem, SpongeBob mailbox, an armed security guard approached. He told me the pictures I was taking were “suspicious” and said I was not allowed to take them. “This is a public sidewalk, why not?” I asked. He then told me I was no longer allowed on the property and to go across the street immediately.

I asked, from across the street, why I could not come any closer to the building.

He said, “You would not want people taking photos of your office, would you?” Ultimately, he asked me to leave.

3. The Department of Health and Human Services

On Friday, a spokesperson for HHS told BuzzFeed that there is “no restriction on photos of our building, so long as you are outside.”

But when I tried to take photos there…

…a guard quickly exited this cement booth and asked what I was doing. “I’m a reporter doing a piece on government architecture,” I said. “Well, you can’t take photos here. Move to the front of the building.”

Around the front of the building, I took this photo of a busted up cement barrier.

The above security guard yelled, “What are you doing? You cannot take photos of our building like that, up close.” I told her I was a reporter and showed her my credentials. She said “I do not care, you can’t do that,” and told me to move along.

4. The Department of Labor

On Thursday, a spokesperson for the Department of Labor confirmed there are no formal restrictions on taking any photos of the building.

But when I tried to take photos there…

…a security guard directly asked me to leave. “The photos you are taking make people here nervous. I have to ask you to leave.” I asked to speak with his supervisor. When the supervisor arrived, I showed him my credentials and explained why I was taking photos. “I can’t have you near the building taking photos. Stay on the sidewalk.” (This was about 25 feet away from the building.)

After ultimately telling me I was allowed to take photos on the sidewalk, the supervisor (below, in white) went from officer to officer around the building, telling them to keep me at a safe distance.

From then on, everywhere I went around the building, an armed security officer trailed me.

“Easy on the pictures,” an officer yelled at me when I snapped this photo of Labor’s Veterans Park.

“Why? It’s a public park,” I told him. “I have orders,” he said. The supervisor had walked up and told him to watch me moments earlier. The officer remained looking over my shoulder, just a few feet behind me the rest of my time at Labor.

5. Housing and Urban Development

A spokesperson for HUD has not returned BuzzFeed’s request for comment on the photo policy.

When I took this photo…

…three armed guards approached me. “You cannot take photos of the building entrance. You have to delete that,” one demanded. I asked them what right they had to make me delete a photo on my personal camera. One of the guards called for a superior and went back inside the building.

When the supervisor arrived, he said he could not force me to delete my photos.

But it would be best if I “left the premises.”

6. The Department of Energy

On Thursday, a spokesperson for Department of Energy Security told BuzzFeed: “There is no problem or restrictions in taking photos of the building,” and simply cautioned against photographing employees.

But when I tried to take photos there…

After I took this photo of a public walkway in front of the building, four armed guards surrounded me and my bike. I was ordered off my bicycle and told to hand over my camera. “Where is your identification? Why are you taking photos of our building?” an officer asked me. I explained my role as a reporter and asked what rules I had broken. “You are suspicious, and we are in a post-9/11 world,” he said.

The four officers surrounded me right here, directly in front of the building entrance.

I could not take their photos since they had my camera. The four armed guards prevented me from moving or getting on my bike. After calling my boss, and discussing with the guards, I was given my camera back. “Be smarter next time,” he said, “and don’t take any more photos here.”

The only building without any problems was the Department of Education.

They apparently have bigger problems to deal with.

Read the whole story
Share this story
Delete
2 public comments
norb
1 day ago
reply
If you have any more interest in this kind of thing check out http://photographyisnotacrime.com/
clmbs.oh
Mother Hydra
3 days ago
reply
All of these security guards and cops should be fired for ignorantly towing the line. Apparently living in a "post-9/11 world" is the blanket excuse for abusing and breaking the law.
Beneath Innsmouth
jhamill
3 days ago
Or the policy on photographs should be the same as the public statements on photographs of government buildings.
Mother Hydra
3 days ago
The disconnect is what angers me. If you don't want people taking photos just out and say so, we know the reasons why. But this whole theory versus reality exercise just makes the guards look incompetent and paranoid. Is this the natural state of existence inside D.C.? I've traveled there for leisure but do not recall all of the spookiness.
jhamill
3 days ago
Indeed. Pick a policy and stick with it.
shamgar_bn
2 days ago
Honestly, I think it would have done this reporter some good to push back just a little to see how they'd respond under a little more pressure. Not that he should have crossed the line himself, but if he's going to probe for a response, go a little further...
d4nj450n
1 day ago
Toeing the line, as you say, means doing just as they are instructed. Do you expect these $10/hr employees to be constitutional experts? Of course they are just doing what they are told. Some one should be fired, to be sure, but your anger is misplaced.

07/21/14 PHD comic: 'Writing'

1 Comment and 9 Shares
Piled Higher & Deeper by Jorge Cham
www.phdcomics.com
Click on the title below to read the comic
title: "Writing" - originally published 7/21/2014

For the latest news in PHD Comics, CLICK HERE!

Read the whole story
Share this story
Delete
1 public comment
iaravps
2 days ago
reply
This is *exactly* how I feel everytime I need to write...
Rio de Janeiro, Brasil

Women Who are Ambivalent about Women Against Women Against Feminism

4 Comments and 10 Shares

So...yeah.   So…yeah.   Right now there’s a lot of talk about a tumblr called WomenAgainstFeminism.   WomenAgainstFeminsm.   It’s just pictures of some women holding up handwritten signs entitled “I don’t need feminism because.. because .”  Some of the reasons they give for not needing feminism almost seem like a parody (“How the fuck am I suppose to open jars and lift heavy things without my husband?”) and some (“I don’t need to grow out my body hair to prove I’m equal to men”) just make me wonder where in the world they got their definition of feminism.

At first I considered starting my own “I Don’t Need _____ Because” tumblr with people holding equally baffling signs.  Signs like:

I don’t need books because YOU KNOW WHO WROTE BOOKS?  HITLER.  HITLER WROTE A BOOK.  NO THANK YOU, NAZIS.

I don’t need money BECAUSE I HAVE A CHECKBOOK, ASSHOLE.

I don’t need air because LOTS OF IT IS FARTS.  I’M NOT BREATHING FARTS.  YOU BREATHE FARTS.

But then I remembered that I’m too lazy to make a tumblr and that this whole thing was a bit ridiculous. Here’s the thing:  Do you think men and women should have equal rights politically, socially and economically?  Then you’re probably a feminist.  There are a million tiny aspects of this to break off into and I get it.It’s complicated.  There’s not just onetype of feminist, just as there’s not just one type of Christian or Muslim, or man or woman.  Hell, there’s not even just one type of shark.  Some are non-threatening and friendly.  Some get sucked up into tornadoes and viciously chew off people’s faces until that guy from 90210 stops the weather with bombs.  (Spoiler alert.)    The point is that sharks, much like feminists, are awesome, and beneficial, and the world would be a worse place without them.  Plus, they’re incredibly entertaining and even if you sometimes think they’re dicks for eating cute seals you still yell “HOLYSHITLOOKATTHAT!” when Shark Week comes on.  I think this is a bad analogy.  Lemme try again.

Feminists are like bees.  They are adorable and fuzzy but people run away from them because they don’t understand that they just want to make things good.  We’d be fucked without bees. Seriously.  And yes, some bees are assholes and maybe one killed your great-uncle and there are some that you give the side-eye to when they start acting crazy but eventually you realize that you have to take the good bees with the bad bees and maybe just be picky about what honey you choose to eat.  Eat the raw honey, by the way.  It’s way healthier.  That last part isn’t part of the analogy.  It’s just good advice from my great-grandfather (beekeeper).  Also, like bees, feminists secrete a non-edible wax and are easily distracted by smoke.

I’ve lost my point.

Wait, no.  I’ve got it again.

it.  

Feminism is inherently good.  It’s not even close to perfect and still needs lots of work and sometimes it gets all fucked up and backward and awful but that doesn’t mean it’s not still worth fighting for.  Now go back and replace “Feminism” with “The human race”.  It works, right?.  That’s because feminists are made of human.  Men and women.  In fact, one of my favorite feminists is Sir Patrick Stewart.

Patrick Stewart, feminist. His mother made 3 pounds 10 shillings for working a forty hour week in a weaving shed. She was also an abuse victim and he’s an anti-domestic violence advocate.

Patrick Stewart, feminist. His mother made 3 pounds 10 shillings for working a forty hour week in a weaving shed. She was also an abuse victim and he’s an anti-domestic violence advocate.   More at the bottom.

I’m not saying you can’t choose to not be a feminist but know what you’re choosing. Don’t make a decision about a group based on the most radical beliefs of a group.  Don’t get defensive if you get deeper and are exposed to difficult ideas about intersectionality and race and gender and colonialism and patriarchy and male liberation.  Just listen.  Some of it will make sense.  Some of it won’t.  Some of it will later when you’re a different person.  Some of it you’ll change your mind about throughout your life and the world will change too.  Some of it is bullshit.  Some of it is truth.  All of it is worth listening to.

And now you get to decide.  Are you a feminist?  Yes?  No?  Well, don’t worry because tomorrow you get to choose again.  And that keeps happening every day for the rest of your life.

As for me, I am a feminist (among so, so many other things).  I believe in equality and I think we still have work to do.  I’m thankful to the men and women who worked to give me the freedom and rights I have today and I am proud to be a part of a movement that I hope will make the world better and safer for my daughter (and for the men and women she’ll share that world with).  I’m happy we’ve come so far and I’m glad that we’re becoming more aware of feminist issues that don’t just focus on straight, white women, even though confronting those issues is sometimes painful. And I’m happy that the womenagainstfeminism tumblr exists.  Because even though I disagree with most of them I’m glad that those women have a platform on which to speak, and also because if we know what the arguments or misperceptions are against feminism then we can better address them.  Or agree with them.  Or ignore them.  Or discuss them with our sons and daughters so they can make informed decisions for themselves.  It’s up to you.

We’re all equally deserving to express our opinion.  After all, that’s what feminism is all about.*

*Or maybe not.  I got kinda confused after the shark analogy went sideways.

Read the whole story
grammargirl
2 days ago
reply
Feminists are like bees.
Brooklyn, NY
Share this story
Delete
3 public comments
diannemharris
2 days ago
reply
I love the bloggess even more!
jmosthaf
2 days ago
reply
This!
Heidelberg, Germany
RedSonja
3 days ago
reply
My god I love both The Bloggess and Sir Pat.
Next Page of Stories