Archive for the ‘Chemistry & The Public’ Category

Awful Idea: Liquid Nitrogen at a Pool Party

Tuesday, June 18th, 2013

There is video circulating tonight of a summer party in Mexico where organizers poured liquid nitrogen into the swimming pool. They weren’t messing around, either—you can see a number of ~10 L dewars being upended into the water.


Of course, this is a very, very bad idea. Under these conditions, the nitrogen (b.p. = −196 °C) quickly boils and displaces all of the oxygen present, causing people in the area to asphyxiate. Remember, it only takes 28 g of liquid nitrogen to displace 22.4 L of air at standard temperature and pressure. The fact that you are asphyxiating is masked by your ability to exhale carbon dioxide normally, so the burning sensation you experience when holding your breath or drowning is absent. Furthermore, the thick fog produced upon mixing the liquid nitrogen and water conceals any distress.

It looks like multiple people were hurt at the party and needed to be rescued.

News reports, updated 21 June 2013: Daily Mail (corrected most of the wrong chemistry, but a caption referencing a reaction with chlorine remains), Latin Rapper Blog (corrected to get the chemistry right; gives ChemBark a shout out, see comments), International Science Times (gets it right, credits ChemBark), Excelsior (gets the chemistry wrong), Fox News (gets the chemistry wrong), MSN Now (gets the chemistry wrong), Huffington Post UK (gets chemistry mostly right, credits ChemBark, but still needs to correct photo captions), NY Daily News (gets the chemistry wrong), The Sun (gets the chemistry wrong), The Telegraph (gets the chemistry wrong in the headline), Popular Science (gets the chemistry right, includes interview and link to ChemBark), Slate (corrected the story to get the chemistry right).

Deborah Blum covered the misreports by the media of the chemistry at play on the Knight Science Journalism (KSJ) site. The post links to ChemBark.

Updated note to media: Many outlets have reported that liquid nitrogen will react with chemicals in swimming pools to generate a poisonous gas. This is almost certainly incorrect. Molecular nitrogen is relatively inert and should not react with anything present in the pool, like “chlorine” (mostly, NaOCl) or water. The danger of adding liquid nitrogen to the pool stems simply from the nitrogen’s boiling and pushing away all of the oxygen around, leaving none for the swimmers to breathe. The cloud that is present has nothing to do with poison gas. Rather, it is the same thing as fog. The liquid nitrogen is cold and cools the air close to the pool to the point that water vapor in the air condenses into very tiny droplets that stay suspended. The cloud is fog, generated from the same effect responsible for your being able to “see your breath” when you exhale on a cold day. The visible cloud is not nitrogen and it is not smoke; it is droplets of water suspended in an atmosphere of air that is heavily enriched in nitrogen.

Sue the “Chemical-Free” Bastards

Monday, June 17th, 2013

Chemical Free Beauty ProductsWhile I’m an idealist at heart, in my old age, I’ve increasingly found myself giving in to apathy and letting things slide more often. In the shower this weekend, I saw another one of my fiancée’s hair-care products advertised as “chemical free” and was soon awash in the same frustration expressed in this old post. The phrase “chemical free” is profoundly stupid, it is damaging to our field, and the problem is getting worse. While a lot of frustration has been expressed by a small group of chemists online, I’ve seen no effective campaign against the stupidity of the term “chemical free.” On the flip side, you’ve got another group of chemists who find the argument against “chemical free” to be pedantic, and some have even embraced the term for use in lab.

While I might be closer to abandoning this cause in favor of apathy, I don’t think the problem is worth giving up on just yet. Previously, I have lobbied bench chemists to become more involved in educating the public, suggested that the ACS develop a “war room” to address misinformation in the mainstream media, and volunteered a first draft of a pro-chemicals ad campaign. But maybe that’s my idealism talking. “Positive” approaches, where we tout the benefits of chemistry, require a lot of effort and take time to bring about change. Perhaps it would be more effective to adopt a negative approach? And, of course, what approach could be more negative than to sue?


Yes, let’s start suing companies that advertise their products as “chemical free”. Make the dummies hurt where it counts: their wallets.

You see, there are laws that require truth-in-advertising, and many of them should be directly applicable to “chemical free” cases. The Federal Trade Commission has explained its policy for how it judges whether or not it will act on potentially deceptive ads:

Certain elements undergird all deception cases. First, there must be a representation, omission or practice that is likely to mislead the consumer. Practices that have been found misleading or deceptive in specific cases include false oral or written representations, misleading price claims, sales of hazardous or systematically defective products or services without adequate disclosures, failure to disclose information regarding pyramid sales, use of bait and switch techniques, failure to perform promised services, and failure to meet warranty obligations.

Second, we examine the practice from the perspective of a consumer acting reasonably in the circumstances. If the representation or practice affects or is directed primarily to a particular group, the Commission examines reasonableness from the perspective of that group.

Third, the representation, omission, or practice must be a “material” one. The basic question is whether the act or practice is likely to affect the consumer’s conduct or decision with regard to a product or service. If so, the practice is material, and consumer injury is likely, because consumers are likely to have chosen differently but for the deception. In many instances, materiality, and hence injury, can be presumed from the nature of the practice. In other instances, evidence of materiality may be necessary.

Thus, the Commission will find deception if there is a representation, omission or practice that is likely to mislead the consumer acting reasonably in the circumstances, to the consumer’s detriment.

So, there are three major criteria for an ad to meet: (i) it must be deceptive, (ii) it must have an impact on a “reasonable” consumer, and (iii) it must induce a material change in behavior on the part of a consumer. Any product which advertises itself as “chemical free” easily meets these three criteria.

First, everything that I have come across as “chemical free” (e.g., cosmetics, fertilizer, sunscreen) has contained chemicals, so the claim is a false written representation of the product. Second, the fear of chemicals is so widespread in society that it is more than reasonable for an average, uneducated consumer to care whether something is “chemical free”. Finally, a “chemical free” label can easily have a material effect in that a chemophobic consumer could choose to purchase a falsely labeled product over a competing product that is not labeled “chemical free” yet contains the same active chemicals.

Unfortunately, it is probably unreasonable for any halfway-decent chemist to claim he was fooled by something as scientifically nonsensical as “chemical free.” But, a class-action lawsuit waged by a group of typical (chemophobic) consumers who’ve purchased a chemical-free product could easily have merit.

Perhaps even more effective would be for a major company (with hefty legal resources) to file lawsuits claiming damages due to unfair business practices. It is unfair to have to compete against rival products that benefit from advertising with false claims. Let’s see these smaller companies have to defend themselves against the giants. Unfortunately, there’s no single chemical-free product on the market that is successful enough to make such a lawsuit a worthwhile cause.

Outside of lawsuits, what can you do? Well, the FTC has an FAQ about what sorts of ads are potentially deceptive, and you can contact them to register a complaint about products making false claims. Some complaints they pursue and some they don’t, but their decisions carry the weight of the law and they can issue cease-and-desist orders as well as fines. You can also register complaints with the Better Business Bureau (BBB) and state/local consumer protection offices.

I’m not saying that lawsuits are the best approach to solving the problem, but in some cases, insisting on the enforcement of existing laws might be an effective solution to the proliferation of all this “chemical free” nonsense.

Chemical-Free Fruit Washing

Monday, June 10th, 2013

A friend sent me the following picture on Facebook:



Cleaning Fruit – Chemical-free and EASY!

Fill sink with water, add 1 Cup of Vinegar, and Stir. Add all fruit, and Soak for 10 minutes. Water will be dirty, and fruit will sparkle with no wax, or dirty film. Great for Berries too, as it keeps them from molding. Do this with strawberries, and they last for weeks!

SHARE this post with your friends!


Oh, I will share this post with my friends all right…

No chemicals, you say? Fantastic! I am glad you’ve managed to remove the acetic acid impurity from your vinegar. 😐

Of course, you’ve seen this on ChemBark already. What I find more interesting are the comments attached to the post:


Oh, you think vinegar works well? Have you tried mixing vinegar and baking soda? It’s magic!

What a discovery!  “Magic” = sodium acetate + bubbles of carbon dioxide.

I bet these people would be frightened to learn how baking soda is made. It’s not exactly the most “natural” of processes.

H/T: M.E. for the link. Thanks!

Today’s Unit Conversion Error: Poop in Pools

Friday, May 17th, 2013

A friend on Facebook brought my attention to a very interesting article from NBC News:

People always worry about pee in the pool, but number two is the No. 1 problem, government health experts say. They found plenty of evidence that someone’s pooping in the pool. It’s not only disgusting, but it’s evidence that people are not following basic hygiene rules, says Michele Hlavsa, chief of the Centers for Disease Control and Prevention’s Healthy Swimming Program.

“It is time to stop treating the swimming pool as a toilet,” Hlavsa told NBC News. “Nowhere else except for the pool is it acceptable to poop in public or pee in public. In other places if we did this in public, we’d be arrested.”

The pool-poo expert went on to say:

“The average person has about .14 grams of feces on their rear end,” Hlavsa said. “If that rinses off into the water, the amount from one person might not be that much. But as more and more swimmers introduce it that much, it does become an issue.”

She’s actually done the math.

“Let’s imagine 1,000 kids go to a water park. They have as much as 10 grams of feces on their rear ends,” she said.  “We are now talking about 10,000 grams or 10 kg. That translates to 24 pounds of poop in the water.”

I am willing to grant Hlavsa’s obscenely high estimate of 10 grams of poo per bottom—which does lead to 10 kg of poo per 1000 bottoms—but that does not equate to 24 pounds! The correct conversion factor for poo (or any other substance at the surface of Earth) is 2.2 pounds per kg.

I am immensely relieved her hypothetical pool contains only 22 lbs. of poo.

ACS President-Elect Tom Barton Seeks Input on Fracking

Wednesday, May 8th, 2013

Tom Barton won last year’s ACS national election for President (and was kind enough to answer our questionnaire about important issues facing the society). Yesterday, President-Elect Barton asked that I share this message with the readers of the blog:

In my ACS presidential year of 2014 I’m considering hosting a symposium on fracking with, of course, emphasis on the involvement of chemicals.  I would appreciate hearing from anyone suggestions for particular areas for inclusion, and potential speakers.  I seek a balanced set of presentations from experts in the various aspects, and would certainly be interested in any germane research.  I myself am not an expert in this arena, but I am trying to get smart in it.  In advance, I appreciate your assistance.

Feel free to weigh in using the comments. I will leave the first…