I’ve had the pleasure of hosting the second season of Sincerely, Chemicals. It’s just me and a camera this time. Very simple.
Subscribe to the Sincerely, Chemicals YouTube channel to receive a new video each week.
I’ve had the pleasure of hosting the second season of Sincerely, Chemicals. It’s just me and a camera this time. Very simple.
Subscribe to the Sincerely, Chemicals YouTube channel to receive a new video each week.
Bisphenol A, or BPA, is used to line food cans and also to make strong plastic baby bottles. Eating large amounts of canned food – particularly canned soups or drinking hot liquids from baby bottles – can result in elevated amounts of BPA being detected in people’s urine. BPA acts as an estrogen mimic – albeit a very weak one – and some research has suggested a link between large doses of BPA and an increase of blood pressure. While this does sound worrying, remember that the dose is extremely important and that the molecules of BPA that do leech into food are too few to have any measurable effect.
The United States Food and Drug Administration (the FDA) conducted a four-year review of over 300 scientific studies and concluded that the traces of BPA that do migrate into canned food are so tiny that they have no effect on human health.
The decision to abandon the use of BPA in baby bottles was therefore based on public pressure not based on safety or on scientific evidence.
The science never suggested there was any safety concern with BPA.
Don’t forget to like and subscribe for more videos from Sincerely, Chemicals.
I started a YouTube channel called Sincerely, Chemicals. It’s inspired by the workshops I’ve been running since 2017 so you can now review the content at home.
Video 2 is below. It’s called “Are Organic Products Safer?”… you already know the answer, but play the 2-minute video to find out why.
If you like these videos, please leave a comment, like and subscribe. That way, I might be encouraged to make more 🙂
P.S. I hope you like the cartoons!
The Naturalness Fallacy is my latest book in the chemophobia series. It’s a quick read that introduces the causes, effects and solutions to the chemophobia problem.
Download this free book as a PDF here.
In 2014, I soon followed up with podcasts, radio appearances, press interviews, a T-shirt Store and twelve more fruit ingredient labels. I’ve done six more customised fruit ingredients labels for private clients. The images have since appeared in textbooks, corporate promotional material, YouTube videos, T-shirts, mugs and aprons.
Momentum built in 2015. Parodies emerged online, and a copycat image appeared in one Chemistry textbook. I started writing about chemophobia and consulting with experts on how to address the issue. In short, it’s very, very complicated, and has deep evolutionary origins. I set a goal to understand chemophobia and provide a roadmap to tackle it effectively.
In 2016, my voluminous OneNote scribblings turned into a book. I have a first draft saved on OneDrive (thank you for keeping it safe, Microsoft) and I’ll be proofreading it on an long-haul intercontinental flight for you later today.
I promise that my book “Fighting Chemophobia” will contain the following:
This “Fighting Chemophobia” book is for:
To get your hands on a copy, subscribe to this blog for email updates. Just click ‘Follow’ somewhere on this page (its location depends on which device you’re using).
I promise that throughout 2017, you’ll receive teasers, snippets and discarded book fragments via this blog to get you excited.
We all feel a profound connection with the natural world. E O Wilson called this sensation biophilia: ‘the urge to affiliate with other forms of life’. That sense of connection brings great emotional satisfaction. It can decrease levels of anger, anxiety and pain. It has undoubtedly helped our species to survive, since we are fundamentally dependent on our surrounding environment and ecosystem. But lately, biophilia has spawned an extreme variant: chemophobia, a reflexive rejection of modern synthetic chemicals.
I first came across Chad Jones when I did an interview with him on The Collapsed Wavefunction back in 2013. We discussed ingredient labelling, chemophobia and my motivations for making the Ingredients of an All-Natural Banana poster series.
Chad Jones works at Intel Corp. in Utah, USA. He’s the founder and chief science writer for The Collapsed Wavefunction, a science advocacy podcast featuring episodes on science instruction, science in popular culture, and current science news items.
In 2016, Chad’s launched his latest venture in chemistry outreach with a fantastic new podcast called Chemical Dependence. In each of the podcast’s punchy, 5-minute episodes, Chad explores interesting chemical compounds and how they’re used in society. The podcast is a great source of interesting facts to liven up any chemistry lesson. All Chemistry teachers should subscribe!
In science education, chemistry is one of the disciplines that involves regular hands-on work in a laboratory. While teaching students the intricacies of chemistry presents no exceptional risk, the very real dangers posed by many chemicals demand a higher level of safety consciousness and preparedness. This general overview outlines sensible security precautions for high school and college chemistry labs.
Fortunately, in a classroom setting, all of the chemicals being used will be well understood. This means information on their potential risks is widely available. This information must be used to ensure that each substance used is treated with the proper respect for the dangers it poses.
The first source of information for any chemical is the label it carries. These always describe their hazards, but labeling may be incomplete. A more authoritative source for hazard information is the material safety data sheet (usually referred to as an MSDS) for the substance. A comprehensive reference collection of MSDSs is an integral part of every laboratory, and this collection needs to be freely available to all teachers using the classroom’s chemical supply.
At the high school or college level, chemistry experiments demand their own dedicated laboratory spaces. These labs should meet all state and national safety requirements and cannot be used for teaching other subjects. Even the scheduling of laboratory use must be geared towards safety. Adequate free periods must be included every day for cleaning the lab and disposing of chemicals.
Chemicals need a dedicated, lockable storage room equipped to contain them safely. A prep room is also required for teachers to use. This needs equipment similar to the lab room albeit on a smaller scale. For all three of these spaces, ventilation is a critical concern. Ventilation hoods should be used in the lab itself and all of the air removed from the lab must be vented outside.
Full safety equipment needs to be available for everyone in the laboratory while chemicals are in use. This includes both permanent safety facilities (e.g. eyewash stations, first aid kits, etc.) and personal protective equipment (PPE), including goggles. Goggles for use in chemistry labs must conform to stricter standards than other forms of eye protection to ensure that they protect against both flying debris and liquid splashes.
Every chemistry lab needs thorough safety plans for both general and specific chemical risks. While standardized materials including the safety documentation discussed above can be used to prepare safety plans, each teacher responsible for leading classes in the lab has a responsibility to set out his or her own safety measures.
Customized safety preparations should take the specifics of the facility and the coursework into consideration. Methods for calling for help, evacuating the lab, and documenting incidents will vary based on the layout of the facility and its resources. By designing their own safety plans, teachers will be better prepared to enact them in the event of an accident.
A chemistry teacher has many responsibilities beyond instruction and safety planning. One of the most important of these responsibilities is teaching his or her students to share a healthy respect for the hazards posed by chemicals. Teaching and testing them on basic safety precautions and lab-specific emergency procedures is just a start.
Students should learn to understand the intricacies of chemical labeling before working with hazardous chemicals. (For example, the terms danger, warning, and caution are each distinct, indicating decreasing levels of risk.) At the college level, where students may be working independently and designing their own experiments, teaching them to read the MSDS is strongly recommended. For younger students teachers can often make use of intermediate-level warning documentation (e.g. CLIPs, Chemistry Laboratory Information Profiles) to give them adequate chemical reference materials.
Keeping students safe in the laboratory is not a difficult job. It requires a heightened sense of awareness and an amount of preparation commensurate with the hazards posed by the chemicals involved. When preparedness is combined with proper facilities, equipment, and training, schools labs can be safe places to learn through direct experimentation with all but the most dangerous of chemicals.
Whether you’re building a new Lab or upgrading your existing one, you will find a remarkable selection of Casework, Workstations, Fume Hoods and related lab products at National Laboratory Sales.
Would you drink water that’s been purified from sewage? Bill Gates did:
He’s talking about the Omniprocessor in Seattle, USA, which illustrates perfectly the prevalence of chemophobia in our society. The Omniprocessor takes sewage waste and purifies it into clean drinking water. The dried sewage is then combusted to power the plant, producing electricity that can be sold back to the grid. Essentially, it’s a free sewage disposal system that also gives you clean drinking water and a plentiful supply of electricity. Omniprocessors could be a huge income boost for farmers in developing countries.
The plant in Seattle was met with resistance. One study showed that 26% of survey participants were so disgusted by the idea of “toilet-to-tap” that they agreed with the statement: “sewage water could never be purified to such an extent that I would be willing to drink it”. Try it yourself: which glass of water would you rather drink?
If science tells us the purified sewage-water is perfectly clean, then why aren’t people comfortable with drinking it?
Paul Rozin at the University of Pennsylvania provides an explanation. He uses the term “contagion” to describe the perceived, permanent grossness that objects or substances acquire once they have touched something disgusting. No amount of purification can remove the ‘disgust factor’ that’s been acquired by the object. It’s purely psychological, and has no basis in science, but might have evolved as a useful behavioural adaptation that protects us from disease.
Mark Schaller at the University of British Colombia coined the phrase “behavioural immune system” to describe this phenomenon. It includes a suite of feelings and behaviours, including repulsion and disgust, that prevent us from eating contaminated food. It’s overly sensitive, and is at the root of many culinary taboos (e.g. don’t eat pork/prawn/insects).
All of this makes evolutionary sense: for millions of years of human evolution, we had no way of purifying food once it had become contaminated. We had no way of boiling water (and no fire) for 90% of human history. We had no modern medicines for 99% of human history, which made even small illnesses a horrifying, life-threatening prospect. Paranoia about cross-contamination has probably saved our species from extinction.
Science teachers are partly to blame. I tell my students never to eat in the lab because we’re fearful of contaminating the student’s food with lab chemicals, which might make them ill. I tell my students never to pour back into the stock solution because we might contaminate the stock solution, ruining future experiments. When an unidentified clear liquid (either pure water or a highly corrosive acid) splashes onto a student’s skin, I tell them to assume it’s the highly corrosive acid and wash immediately with copious amounts of water, just in case. Science teachers inadvertently instil in students a fear that laboratories are highly contaminating places. We do this with the absolute best of intentions.
Paranoia about contamination in laboratories has likely prevented countless accidents worldwide. It’s saved lives and limbs, too, and that’s why teachers must keep emphasising these safety messages. In doing so, however, do need to be mindful of the the unfortunate side-effect of ‘contagion’, which is the gut instinct that foods and lotions (or even water) created in a lab must be contaminated with something nasty. We need to counteract that notion in the following way.
When my students made aspirin last week (about 8 tablets’ worth), I told the students we cannot ingest the aspirin because “it’s contaminated: it contains unknown impurities”. Similarly, when we made esters last term (edible artificial flavourings), I told the students not to touch the esters or smell them too closely because they “contain contaminants such as highly corrosive sulfuric acid”. These safety warnings are valid and necessary – they’re actually a legal requirement of my job.
In industry, however, both aspirin and esters (and everything else) would be purified after production to a very high standard (usually 99.99%) before being certified safe for human consumption. Generally, however, high-school chemistry students don’t learn about purification techniques – not even in theory – so for them, the laboratory remains a dangerous place where dirty, contaminated things are created. Inadvertently, that’s become the take-home message from high-school science.
“…for [students], the laboratory remains a dangerous place where dirty, contaminated things are created.”
Purification techniques such as fractional distillation, centrifugation, recrystallisation, affinity purification and liquid-liquid extraction are all beyond the scope of a high-school chemistry course. Water purification and extraction of substances using supercritical carbon dioxide (scCO2) are in the Year 11 textbook, but these topics are not taught by many schools. Students don’t need to know the details – but they do need industrial relevance built into their course, and they need to be made aware that many of the products we use were made or designed in labs. Most importantly, they need to know that these products were purified to a high standard before being put to use.
After years of hearing these messages in school, it’s no surprise that some people are so averse to eating foods or using products made in a lab. As one of my survey respondents put it so succinctly:
“If I can’t eat in a lab due to fear of contamination, how could food made in lab possibly be safe to eat? If I have been taught to treat every lab chemical that gets onto my skin as potentially corrosive, how could a moisturiser made in a lab from synthetic ingredients ever be good for my skin? This goes against what I’ve been taught throughout school!”
Science education in schools might just be one of the root causes – and one of the solutions – to the widespread prevalence of chemophobia. More next week.
This post is part of a weekly series on chemophobia. Read part 1 here.
About the artist: Liu Bolin imbeds himself and others into the photograph, declaring their position as individuals within the catastrophic incident, thus calling viewer’s attention to the aftermath and investigation of the disaster. Through recreating the imagery of the damage and devastation caused by the explosion, the project is Liu’s attempt to reveal social issues in China, as well as to reflect on the complex relationship between the past and the present, the reality and the illusion, as well as individuality and society. Visit Liu Bolin’s gallery page here.
As a Chemistry teacher, my initial reaction to the enormous explosions at a hazardous chemicals storage facility in Tianjin, China this week was a need to find out what exploded and why. As soon as the news broke, I started following #Tianjin on Twitter and getting alerts from Google News. Here’s what I’ve learned about the Chemistry behind these two fatal blasts. We know there were several dangerous chemicals on site. We also know that firefighters were present at the facility putting out a fire before the first explosion. The second explosion was much larger than the first, with the two blasts measuring the equivalent of 3 and 21 tons of TNT, respectively. The second, larger blast was so powerful that it caused a magnitude 2.9 earthquake in the surrounding area. For a surface explosion to cause a measurable earthquake is rare.
Here’s my understanding of what happened.
An unknown substance caught fire inside one of the storage containers at the facility. Firefighters arrived at the scene to douse the flames with water.
CaC2(s) + 2H2O(l) → Ca(OH)2(s) + C2H2(g) ΔH = -127.7 kJ/mol
Calcium carbide, CaC2(s), is an unstable compound that’s used in the production of acetylene (ethyne) and also in steelmaking. When water (or moist air) touches calcium carbide, it fizzes gently, releasing acetylene gas, C2H2(g), which, when mixed appropriately with air, explodes upon ignition. The reaction above is only slightly exothermic, and the ethyne gas released is colourless and odourless: it’s possible that the firefighters didn’t even notice that the gas was being produced.
After the ethyne had mixed sufficiently with the surrounding air, one part of this explosive gas mixture was ignited by the pre-existing flames, causing the first explosion.
C2H2(g) + 5/2O2(g) → 2CO2(g) + H2O(g) ΔH = -1299 kJ/mol
Eyewitness reports have estimated this first explosion to be equivalent to 3 tons of TNT, which equates to 12.5 million kilojoules of energy. Using n = E/ΔH, we find that around 9662 moles of ethyne appears to have exploded. Using V = n×VM, we can calculate that at 25°C and 1 atm of pressure, that explosive gas would have occupied a volume of 236719 litres. Using r = (3V÷4π)1/3, we can approximate the ethyne gas to have occupied a sphere 76 metres in diameter, which is (very approximately) consistent with what we’ve seen in the video footage.
Interestingly, we can do a simple stoichiometric calculation using m = n×Mr and calculate the initial mass of calcium carbide that decomposed: 9662 × 64.1 = 619 kilograms. At a density of 2.22 g/cm3, those 619 kilograms would have occupied 279 litres in powdered form: this is about the same size as three large luggage cases.
A quick search on Chinese wholesale directory Alibaba.com shows that very few companies offer calcium carbide in such small quantities, which might help narrow down which company was responsible. Interestingly, the raw material for that first explosion was worth a mere US$400 at 2015 wholesale prices… but the consequential damage was far more costly.
Temperatures of over 3000°C were generated by the combustion of the ethyne in stage 3. The immense heat from that initial fireball heated the surrounding containers to above 240°C, which initiated a runaway decomposition reaction of ammonium nitrate, NH4NO3(s), which was stored nearby. The reaction is shown below.
NH4NO3(s) → N2(g) + 2H2O(g) + 1/2O2(g) (ΔH uncertain)
The enthalpy change for the reaction above wasn’t easy to find, but this book by Sam Mannan claims it to be 0.175 million kilocalories per tonne, or 732,000 kilojoules per tonne. Analysis of the video recordings have estimated this second explosion to be around 21 tons of TNT equivalent, which equates to 88 million kilojoules of energy. Using calorimetry formula m = E/heat of combustion, we can estimate the mass of ammonium nitrate in this second explosion to be 8300 tonnes, which seems extremely high: four times as big as the Texas City Disaster of 1947. Either the second Tianjin explosion was the biggest ammonium nitrate disaster in history, or I’ve made an error in this part of the analysis. Let’s wait for more information and see.
The above reaction has caused hundreds of fatalities worldwide in the last 100 years. Smaller incidents occur every 2 or 3 years worldwide, around half of which are fatal. Gases are produced under extreme temperature and pressure, which expand outwards and destroy almost everything in their path. Ammonium nitrate is supposed to be handled and stored under very strict government regulations. These rules aren’t always followed (or understood) in rapidly-developing countries such as China.
The products of these two explosions are calcium hydroxide, carbon dioxide, water vapour, nitrogen and oxygen, which pose zero risk to nearby residents. However, the main concern now is that other (non-flammable) hazardous chemicals such as sodium cyanide, NaCN(s), might have been tossed into the air following the first two explosions. Residents living within 3 kilometres of the blast site have been evacuated as a precaution.
Fortunately, satellite imagery shows that almost all of the smoke plume was blown eastwards over the ocean, and not back westwards and back onto the city. We’ll get a clearer picture when China’s chemical experts report their findings in the next few days or weeks.