I Can't Believe It's Not Science

I accidentally volunteered to work at an organic vegan soup kitchen earlier this year. 

It was an unsettling experience, for a number of reasons: they took donations of food for the benefit of inner-city hipsters rather than the hungry. It involved “organic” food, a term that makes people who’ve taken an actual chemistry class roll their eyes. They made mashed potatoes using margarine, which is an affront to everything I value. And, since the produce was “organic”, some of the people working in the kitchen - none of them trained cooks - believed it didn’t actually need to be washed. 

I am only a partially-trained cook - I quit culinary school after a professional chef disagreed with me over the existence of anaerobic bacteria. (True story.) However, I am trained enough to recognise grotesque breaches of food safety standards, so please trust me here: produce ought to be washed.

We all encounter food on a daily basis, and so food seems to spark a lot of the more bizarre scientific misunderstandings I come across. It makes me sad to think that people I know might be depriving themselves of an pre-exam all-nighter fuelled by Diet Coke and Mie Goreng noodles, simply because they’ve been told that aspartame and MSG will cause their internal organs to run away in the night.

So, here is a collection of food myths I’ve come across in person: in the organic vegan soup kitchen, at culinary school, posted on my Facebook wall.

“Organic produce doesn’t need to be washed! It’s chemical free!” For reasons which I have previously explained, organic produce is not chemical free. It is not intangible. It is not made of rainbows and the dreams of leprechauns. It’s made of chemicals like carbon and water and vitamins and then it’s treated with (organic!) fertilisers and herbicides and pesticides. (Unless the organic farm has decided to use manual labour instead of herbicides, in which case labourers remove weeds from the crops by hand, leading to crippling injuries.) 

When we say organic fertiliser, we generally mean compost or manure. Manure is cow poop. Cow poop was in the vicinity of your vegetables, and then your vegetables were picked by someone who probably wasn’t washing their hands on a frequent basis, and then your vegetables were transported and unloaded by more bare hands and then prodded by an untold numbers of strangers with unknown personal hygiene standards until you chose that one particular head of lettuce. WASH YOUR VEGETABLES.

“If you leave a McDonald’s cheeseburger out of its package it will never rot! It’s not even food!” A McDonald’s cheeseburger patty is made of ground beef and salt. That’s all. But a patty weighs less than fifty grams and is the size of my palm, and because of this high surface-area-to-volume ratio, it’s really easy for any moisture contained in the patty to evaporate when it’s left in the open air. Without moisture, bacteria cannot grow, and the burger will not decay. I considered test-driving this myth by using a control hamburger that wasn't dehydrated, but decided against it for two reasons:

1. If there's a cheeseburger in my house, I'm going to eat it, I don't care if it's a month old.
2. The amazing Kenji from Serious Eats already tested this myth very rigorously.

There aren't any mystery preservatives in McDonald's cheeseburgers. They turn over far too much product, far too quickly, to necessitate the expense of adding extra preservatives to their meat. Also: if the idea of salt and dehydration being used to preserve food is a new concept, then the deli counter at your local supermarket is going to Blow. Your. Mind.

“I’m, like, totally allergic to MSG.” Wow, that sucks! I can't imagine not being able to eat tomatoes or parmesan cheese or Vegemite or any other foods containing naturally-occurring glutamates. Wait - you're NOT actually allergic to glutamates? You just experience a vague sense of ill-health after overindulging in Chinese food? Well, that's been debunked. MSG also won't give you asthma. The evils of MSG, like aspartame, are one of those strange myths that's been tested for decades and debunked every time, and yet still persists through the menace of chain emails.

"But if MSG isn't dangerous, why does every single Chinese restaurant have a big NO MSG sign in their window?"

To be fair, this is a little bit backwards: in the comic, the cereal is advertised as not containing asbestos, even though none of the cereals contain asbestos. (This is similar to olive oil bottles with "NO CHOLESTEROL" written on them.) Conversely, when restaurants advertise that they don't use MSG, it's not because MSG is dangerous - it's because every other restaurant in town has the same sign. You can also see this phenomenon in the milk aisle of the supermarket, where every second bottle has suddenly become "permeate free!"

"Margarine is only one molecule away from being plastic." There are many reasons to avoid margarine, such as:

• The taste
• The taste
• The taste

However, for people who watch out for animal products and/or saturated fats, margarine is a viable butter alternative. It also lasts longer without proper refrigeration (which explains the ubiquity of Blue Band margarine in South East Asia). Is it one molecule away from being plastic? I don't know, and I don't care.

Peroxide bleach is one atom away from being water. Table salt is one atom different from hydrochloric acid. To make a food - or anything else, for that matter - there's only 118 elements to choose from, and only 98 of them occur naturally, and only 80 of those are actually stable. Pretty much everything you encounter in daily life is made of some combination of those 80 elements. Fewer than 30 of them have any dietary value. So, there's necessarily going to be a lot of overlap in the chemical composition of the food you eat.

"Jelly is made from animal hooves! Red food colouring is made from ground-up bugs! Sugar is an animal product!" Actually, these are all true - gelatin is extracted from animal bones, and the food colouring cochineal is, indeed, made from crushed insects. Refined white sugar can be filtered using bone char, which renders it an animal product if you're a strict vegan or obeying religious dietary guidelines.

"You should come eat at this organic soup kitchen!" You should probably ask to see the kitchen before you do this. Please make sure they're washing the vegetables.

On Chemical Burns, Vinegar and Liquefied Chicken Feet

“This is a chemical burn.” - Fight Club.

So says Tyler Durden, after he pours lye over the hand of Tyler Durden to teach Tyler Durden that he needs to lose control and place his life in the hands of Tyler Durden. Then, Tyler Durden pours vinegar over Tyler Durden’s hand to neutralise the burn.

(If the phrase “Tyler Durden” no longer means anything to you after reading that paragraph, you’re experiencing a phenomenon called semantic satiation.)

Does lye burn like that? Should you really pour vinegar over it? Can a chemical burn actually induce visions of Helena Bonham Carter in an ice cave?

Lye is another name for the chemical sodium hydroxide, or NaOH. You might have used it in the form of Drano, because it will quite happily dissolve whatever gunk is clogging up your sink. It is, indeed, used in soap making as an agent to saponify fat. It’s also used for disposing of larger objects such as animal carcasses and drug cartel enemies. Put simply, NaOH likes to eat things.

In its powdered form, as shown in the movie, sodium hydroxide will just sit on your skin until you get rained on, or start sweating, or find some other way to introduce moisture to it. It’s hygroscopic, which means it likes water so much it will eventually just start taking moisture from the atmosphere. When it does get wet it turns into a strong alkali, capable of turning your hand and any other body parts into a gross, soapy mess. This is why Tyler Durden kisses the back of Tyler Durden’s hand before he pours the lye over it - to leave moisture for the burn to occur. 

The burn is caused by a chemical reaction between the hydroxide (OH) part of the sodium hydroxide, and the glycerine and fatty acids (triglycerides) in the skin. The end products are soap and glycerine, which is used in the food and pharmaceutical industry (and yes, Tyler was correct when he stated "with enough soap, you can blow up anything" - glycerine is an ingredient in dynamite). 

If you spill a weak concentration of sodium hydroxide solution on your hand, you’ll experience itching and stinging, as well as the uniquely unpleasant sensation of being able to lubricate your hands with your own slowly-dissolving skin as you wash it off. Higher concentrations will cause deep burns and nerve damage, as well as blindness if you're unlucky enough to get it in your eyes, so kudos to Brad Pitt for wearing his safety goggles.

Here's a video of sodium hydroxide being used to break down a chicken foot. This is also an example of how NOT to create a sodium hydroxide solution - more on that later.

For a personal touch, below is a photo of my own foot. The little red mark is where I dropped a 20% solution of sodium hydroxide on it about six months ago. It's not particularly impressive, but it’s worth noting that at the time I spilled it on my foot, I was wearing both shoes and socks. (I'd like to pretend I did this as a public service to demonstrate the importance of safety in the lab, but actually I just broke the bottom off a test tube by smacking it against a benchtop.) Yes, it hurt; no, I did not experience delusional visions of Helena Bonham Carter.

So, imagine you’re at home one day, and your underground soap-making business is going so well that it’s time to render another pile of fat (human or otherwise). You spill sodium hydroxide on your hand, and it’s just damp enough that it starts to react with your skin. Is it time to break out some vinegar to neutralise that burn?

It’s true that the reaction between an acid and a base is a neutralisation reaction: acids have free hydrogen ions (H⁺) , and bases have hydoxides (the “OH” in NaOH - to be accurate, it's OH^- and has a negative charge). Together, they form neutral H₂O: water!

And heat. Did I mention heat? Because this reaction is exothermic, which is to say, it releases energy in the form of heat. So in addition to the chemical burn, you're also heating up your skin. In fact, the chicken-dissolving video at the beginning of this post actually demonstrated a really ill-advised method of creating a sodium hydroxide solution: adding a small amount of water to a large quantity of sodium hydroxide can cause it to boil or explode.

Warning: this next section gets ridiculously detailed, but there is a summary at the end if you'd prefer not to read 800 words about enthalpy.

If you consult the material safety data sheet (MSDS) for NaOH, you’ll see that the recommended course of action after skin contact is a visit to the safety shower - ideally, you’re going to be flushing the burn with water for at least fifteen minutes. That’s because, even though the reaction between NaOH and water is also exothermic, you’re going to have a much larger quantity of water available compared to vinegar (and the vinegar is mostly water, anyhow). Rather than just neutralising the alkali, it’s better to use a large amount of water to dilute and wash it all off.

(Before you get to dumping water on your hand, it would also be a good idea to turn that hand upside down so that any excess powder on the skin falls off. The less powder on the skin, the less powder will be reacting with water, and the less heat will be liberated.)

Let’s assume that the amount of NaOH left on Tyler Durden’s hand was around a quarter of a cup (so, just short of 70 cm³). Powdered NaOH weighs about 1 gram per cm³, so that’s about 70 g of NaOH. The molar mass - the mass of 6 x 10²³ molecules of NaOH - is around 40 g, so 70 g contains almost 2 moles of NaOH. This means that we need 2 moles of vinegar (acetic acid) to neutralise it.

Vinegar is usually 5% acetic acid by weight. Since the molar mass of acetic acid is around 60 g, that means we need 120 g, which is the amount of acid in 2.5 litres of a 5% solution. You have to aim around 2.5 litres of vinegar squarely at the burn to neutralise all of the NaOH. The amount of energy given off by this reaction is on the order of 50 kilojoules per mole, which is 100 kilojoules in total. That's enough energy to heat the entire 2.5 litres of vinegar by about 9 degrees Celcius. 

If you used a smaller volume of acid (for instance, if you reasoned that one cupful of an 8-mole-per-litre solution of acid contained the 2 moles necessary for neutralisation) the temperature change would be greater. If you were to use only one cupful of liquid, it would actually boil on contact with the sodium hydroxide. (This is why the common suggestion to wash the burn with a little bit of vinegar before rinsing with water is such a bad idea.)

These calculations assume you're taking your hand and dunking it in a tub of vinegar, rather than pouring it over the skin. In reality, much of the benefit would come from the action of using those 2.5 litres of vinegar to physically wash the sodium hydroxide from the skin. Alternatively, you could stand under a shower for fifteen minutes, which would dispense almost 150 litres of water. Dissolving 2 moles of sodium hydroxide in water also liberates almost 100 kilojoules of energy, however, in such a large volume of water the temperature change is negligible.

So, in short: you can fumble your way through opening a jug of vinegar and pouring it over your hand (which would be especially tricky if it's your dominant hand that's burned), or you can turn on a tap and dispense a much greater amount of water to rinse the skin. Either way, your best course of action is focusing on removing the sodium hydroxide powder from your hand, rather than trying to neutralise it. 

And unless you're applying water with an eye-dropper, Tyler Durden's assertion that "you can run water over your hand and make it worse" is just not true. Don't stand around with your hand burning because you're scared to put water on it! The greater the volume of water (or vinegar) you use, the more heat from the dissolution or neutralisation of the sodium hydroxide will be absorbed by the water rather than by your skin.

Obviously, nobody is actually taking chemical safety advice from Brad Pitt movies ...well, except for all these different soapmaking websites, seriously, every soapmaking website ever. One of them actually suggests pouring milk in your eye if you get some lye in there. Unless you have enough milk to irrigate your eye for fifteen minutes, this is not a good idea. I would also advise against accidentally swallowing lye and then chasing it with citrus juice, as suggested here.

Okay, so this turned out way longer than I'd planned. Here's the tl;dr version: when you dissolve NaOH in water, the energy that was holding the molecules together is released. It's called the enthalpy of dissolution. Similarly, when you neutralise NaOH with acid, it releases an amount of energy called the enthalpy of neutralisation. 

In the case of NaOH, these two enthalpies are actually pretty similar: about 50 kJ per mole of NaOH. Because the temperature change during the dissolution/neutralisation is a function of the volume of liquid used, you're better off dousing an NaOH burn in water. This is because you will have a lot more water available than you will have vinegar - to run a shower to flush the skin for fifteen minutes will use around 150 litres of water. 

Either way, the worst thing you can do is using too little water or vinegar - some soapmaking websites suggest "rubbing a splash of vinegar" on the burn. This will actually cause the NaOH to boil on your skin, creating a thermal burn on top of your chemical burn. So: don't do that.

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In the week that It Only Adds has been active, there's been just over a hundred page views, so thanks for stopping by! Over the next few posts I'll be addressing some of the most important scientific questions of our time:

• Can you really neutralise a chemical burn with vinegar, or did Tyler Durden lie to us?
• How did Walter White eliminate a drug lord using a wheelchair and instant cold packs?
• Is it possible to overdose on homeopathic sedatives?

Thanks again for visiting. Here, have a Science Hug:

Neil deGrasse Tyson and Bill Nye the Science Guy

Gonna Wash That Science Right Out Of My Hair

Back in 2010, the Royal Society of Chemistry offered a one-million-pound prize to anyone who could create a product that was chemical-free. It hasn’t been claimed yet, which is odd, because I see things advertised as chemical-free all the time. What’s up with that?

Yes, this is a photo of a chemical-free chemistry set.

Everything you can touch/eat/drink/breathe/wash your hair with/use as a fertiliser is made of chemicals. Matter is made of chemicals. If your shampoo bottle says it's not made of chemicals then it’s made of something intangible like love, or starlight, or unicorn fur, which is lovely but won’t do much in the way of personal hygiene. 

“Chemical” has become some sort of code word for bad and scary and unnatural, and that makes me sad, because chemicals? Are AWESOME. Go get some table salt. Put it on some hot chips. Amazing. While you’re eating, remind yourself that table salt is just little crystals of NaCl, or sodium chloride. Individually, those elements are a toxic gas that can be used as a chemical weapon, and a metal so temperamental that it reacts violently with water. And yet, they can be combined to form something you can safely lick off your hand before a tequila shot. Science!

In 2008, people complained to the British Advertising Standards Authority that “chemical-free” was a nonsense term designed to strike fear in the hearts of people who maybe didn’t quite understand the word “chemical”. The ASA responded: "When there is a colloquial understanding of a word, we can take this into account when reaching our decision... we believe that most viewers are unlikely to be misled by the claim." That’s a bit charitable, though, considering how many times I've seen people reject food, cosmetics and even medicine out of fear of "all those nasty chemicals."

So, every week I’ll be featuring products I’ve found that are “chemical-free." Our inaugural winner is the Australian company Pure Earth (and I should really get in touch with them and ask if they’re aware they could be the lucky winner of a million pounds). Let’s hear from them:

“Pure Earth specialises in the best Australian chemical free products available and as the world subjects us to more and more of these chemical nasties, it is not surprising that we are rebelling against their growing intrusion into our lives as we learn more of the hidden dangers of their increased usage. Synthetic chemicals are everywhere and many of them are downright dangerous! Not only are they in the products we use on our skins and in our environment, but in our food and water supply yet more of these chemical additives are being investigated as possible carcinogens and many of them are already well documented as such!”


… Okay, then.

Pure Earth sells chemical-free home and personal care products, like shampoo and cleaning products. This is a bit confusing, since their shampoo contains ingredients such as water (a chemical!), sodium chloride (also a chemical!) and sodium olefin sulfonate (not a chemical! Just joking, it’s totally a chemical). 

This is generally the point where one hears, “but we mean no dangerous chemicals!” (Yes, I used to work in the beauty industry.) In fact, Pure Earth has a whole page devoted to educating us about the dangers of regular shampoo ingredients. (Please don’t waste your time looking for a reference list; there isn’t one.) For instance, did you know that “Sodium Lauryl Sulphate (SLS) has been traditionally used as an engine degreaser and industrial garage floor cleaner?" This is an odd statement to make, since lots of common household substances are also used in industry - for example, vinegar (or to use its Evil Chemical Name, acetic acid) is also used in the production of glue and photographic film. 

Every chemical comes with a Material Safety Data Sheet, or MSDS. For fun, here’s an excerpt from the MSDS of the sodium olefin sulfonate used in Pure Earth shampoo: “WARNING!! MAY CAUSE EYE IRRITATION. SKIN IRRITANT... In case of contact, immediately wash with plenty of soap and water for at least 5 minutes. Seek medical attention. Remove contaminated clothing and shoes. Clean contaminated clothing and shoes before re-use.” Sounds promising.

Now, of course we’re talking about concentrated, industrial quanitites, nothing like what you’d experience in handling shampoo. But this is the same cherry-picking of data that’s being used to justify not using a chemical like SLS that’s also found in floor cleaner. Do you know what else is found in floor cleaner? And highly concentrated acid, and chlorine bleach, and most likely a bunch of other things you wouldn’t want in your hair? C'mon, guess. Is it arsenic? Uranium? The tears of labrador puppies?

It's water. (So yes, technically, the tears of labrador puppies.) But of course! Big Pharma doesn't want us to know about the risks posed by H₂O, because of the Powerful Water Lobby/the government/the Illuminati etc etc etc.

Obviously, this is nonsense. (And if you'd like to learn more about the dangers of water, this site is an entertaining resource.) There is nothing in Pure Earth's products that makes them "safer" for anyone without a specific sensitivity to regular shampoo ingredients such as SLS. And on the off-chance that you do have a skin sensitivity, that's a matter that belongs in the hands of a dermatologist, not a company that doesn't actually understand the meaning of the word "chemical".


If you see a product that's a contender for the ONE MILLION POUND PRIZE, shoot me an email at itonlyadds@gmail.com. Here's a handy bingo card for identifying potential winners: