Post 150: Choice Chronicles of the Chronicle Flask

From citric to hydrofluoric, acids are an ever-popular topic

I began this blog in 2013, and since then I’ve written at least one post a month. This will be the 150th.

I put love and care into all my posts and, in turn, this blog has been good to me. Although no one’s ever paid me to write it, it has brought me work over the years – many people have asked me to write for them having read things here. But life is busier now than it’s ever been, and it’s time to wind things down. You’ll continue to find my non-fiction here and there, I’ll still be regularly updating my fiction blog, and if you want the latest info, look me up on Twitter. In particular, check out the #272sci hashtag for tiny bits of bite-sized science.

In the meantime, how about a little reminder of some of this blog’s most popular, most important, or just my favourite, posts? Let’s go!

The acid that really does eat through everything (2013)
Turns out, everyone loves acid – this post is one of my all-time most viewed. I guess there’s just something compelling about substances that can dissolve metal, and this one is particular special (and terrifying) for its ability to also dissolve glass and ceramic. (Oh, and sorry about the double spaces after the full stops. It was a long time ago. I know better now.)

Butyric acid, a very smelly molecule (2014)
On the subject of acids, this has been another popular post. I suppose if there’s anything more fun than an acid that eats through the bottle you’re trying to store it in, it’s an acid that smells of Parmesan and vomit. Seriously, it is an interesting one: we’re all familiar with the smell of ethanoic acid (aka acetic acid, found in vinegar), and propanoic acid (propionic acid) merely smells a bit sweaty, but add one more carbon and, hoo boy, you have an utterly revolting stench that some people are so sensitive to they can still detect it weeks, even months, after cleaning.

It’s important to understand what sugar actually is if you want to reduce your intake

Sugar that’s not sugar? (2015)
People talk a lot of nonsense about sugar. A particular pet hate of mine is people calling products sugar-free when they’re nothing of the sort, or implying that the type of sugary ingredient they’ve put in the thing they’re trying to sell you is somehow extra-healthy. If actually reducing your sugar intake is your goal (and it’s not a terrible one), this piece might help.

MMS and CD chemistry – the facts (2016)
This is my simple explainer about MMS (‘miracle’ or ‘master’ mineral solution) and CD (chlorine dioxide). This horrible, nasty fad seems to have faded away in recent years – partly thanks to the fact that even its founder, Jim Humble, admitted it cures nothing – but then again, I have seen CD-MMS linked to pseudoscientific Covid ‘cures’. Let’s hope this post continues to do its job as a useful reference for anyone that needs it.

Absurd alkaline ideas – history, horror and jail time (2017)
Continuing the theme of health, I’ve written several posts about so-called ‘alkaline’ diets, and this isn’t the most popular (that would be Amazing Alkaline Lemons?) but this is the one I wish more people would read. It explains where the whole silly notion came from in the first place. (As does this Twitter thread, slightly more succinctly.)

There really is no need to panic about slime

No need for slime panic: it’s not going to poison anyone (2018)
I’ve yet to meet a child who doesn’t love slime, and every now and then the gooey stuff becomes so popular that we start to see scare stories. So it was in 2018. However, with a few sensible precautions, slime really isn’t dangerous. It’s all explained here.

Let’s speed up the rate at which we recognise our female chemists (2019)
This one was all about the little-known Elizabeth Fulhame. She was the first chemist to describe catalytic reactions – in 1794, when the more famous Berzelius was a mere teenager. Let’s remember her name.

Chemical connections: dexamethasone, hydroxychloroquine and rheumatoid arthritis (2020)
Covid hit us in 2020, and it would prompt more than one post – including this one when dexamethasone had its moment in the spotlight. Probably an unfamiliar drug to most people before this point, dexamethasone was one of the first practical treatments for rheumatoid arthritis in the mid-20th century. Unlike some other much-hyped treatments, we have solid evidence for the effectiveness of this medicine – although it is really only useful for people suffering with very severe symptoms. Still, it’s pretty cool that an old drug turned out to be such a useful tool in a modern pandemic.

There’s chemistry in your skin

Sunshine, skin chemistry, and vitamin D (2020)
To make it a nice, round ten, I’ll sneak in another 2020 post. This one is all about vitamin D. A lot of people are very critical of supplements, and while I understand their position, this particular case is slightly different. If you live in certain parts of the world, you really, really should be considering vitamin D supplementation for at least part of the year, and this post will tell you why.

Brilliant Bee Chemistry! (2021)
This one wasn’t so long ago, but I love it. Bees are fascinating creatures, and if you don’t know what the connection between bees and bananas is, you ought to have a read.

So, this is it, folks – thank you, it’s been fun! Happy New Year!

Content is © Kat Day 2022. You may share or link to anything here, but you must reference this site if you do. You can still support my writing my buying a super-handy Pocket Chemist from Genius Lab Gear using the code FLASK15 at checkout (you’ll get a discount, too!) or by buying me a coffee – just hit this button:
Buy Me a Coffee at



Jellyfish and wee – should you rely on the movies for first aid advice?

Hello and welcome to ‘the chronicle flask’, a blog of interesting chemical bits and pieces. Jumping right in, we begin with a tale of jellyfish, wee and wittertainment.  Here goes…

ImageLast week I was listening to the Kermode and Mayo ‘wittertainment‘ film podcast in which the esteemed film critic Mark Kermode was discussing the film The Paperboy.  There’s a scene in this film in which Nicole Kidman’s character wees (urinates, for the benefit of any non-Brits) on Zac Efron‘s jellyfish sting. It’s an idea that’s been used before, famously in an episode of Friends, and the question arose: does this actually work?  For those that aren’t aware, Simon Mayo is also an author of the rather wonderful Itch series of books, which hinge around a character with an interest in chemistry, and he wanted to know what the chemical equation might be for the wee + jellyfish venom reaction.  So, being a chemist and a big fan of the show, I fired off an email on this very subject.  Here it is:


First of all a quick reminder of the pH scale: it goes from 0-14 where 0 is very, very acidic (think battery acid) and 14 is very, very alkaline (think drain cleaner), and 7 is neutral (think water).

I mention this because acids neutralise alkalis, and vice versa.  If you mix exactly the right amount of acid with the right amount of alkali you get just water and salts.

Since you asked for an equation the general one is:

acid + alkali –> salt + water

Human urine is, actually, about pH 7, i.e. the same as plain water.  People often think it’s alkaline because they have the idea there’s ammonia in it, but there isn’t and it’s not (well not usually).  It varies a bit from 4.6-8, and if anything it tends to be a tiny bit acidic.  If you have a urinary infection it can become more acidic, but we’ll assume for our purposes that Nicole Kidman didn’t.

Jellyfish venom not surprisingly varies by species.  I’m relying on the internet here as I’m not a zoologist, and it seems that there are lots of different varieties of jellyfish in Florida, so the sting could be anything.  But as far as I can work out, they tend to be alkaline (greater than 7).

So if jellyfish venom is slightly alkaline, and human urine is slightly acidic, one MIGHT neutralise the other, and this is probably what lies behind this.  Obviously TV shows and films like this endlessly perpetrate the idea, so it sticks.  In truth this ‘remedy’ is unlikely to do anything much though.

In fact it might actually make it worse.  The proper, official medical advice is to rinse the area with salty seawater, because that apparently deactivates the stinging cells whereas plain water (and urine is closer to plain water than seawater) makes it worse – I imagine this is to do with osmosis, but that’s a lesson for another day – try and remove the stinging cells by scraping the skin with a credit card and, obviously, seek medical attention.

Whatever you do don’t try battery acid.  That’d be really bad.


I was then contacted by the editor of the show, and they actually invited me on to explain this as a special guest.  This, as you might imagine, made my week – I don’t think they’ve ever had a non-film guest on the show before.  If you’d like to hear it, you can download it here.  The shows used to only be available for about a week but they now seem to be hanging around a bit longer (hurrah!).

Now since this is supposed to be a chemistry blog, I have a few more musings on the topic of animal stings.  Jellyfish aren’t the only creatures to have this sort of defence mechanism of course, and probably more familiar to us here in the UK are the humble bee and wasp.  Bee stings are acidic, whereas wasp stings are alkaline.  So can you treat them with household acids or alkalis?  I think, to my shame, that I may even have suggested vinegar as a treatment for wasp stings myself in the past.

Now that I actually think about this for more than 30 seconds I realise that this is very unlikely to be effective.  First of all, wasp venom is complicated stuff.  After all it’s not as if the wasp is injecting a few drops of pure alkali into your arm.  No, wasp venom contains, amongst other things, enzymes which help to break down cell membranes and a chemical to reduce blood flow called norepinephrine, which is why the sting hurts for ages and doesn’t immediately get flushed away by your bloodstream.  The sting itself is a tiny amount of fluid, and only a minute amount of acid would be required to neutralise any alkali present.  So will sloshing an unknown quantity of an unknown concentration of acetic acid (the acid in vinegar, also known as ethanoic acid) actually achieve anything?  Especially considering that the sting is injected under the skin, whereas you’re dribbling the contents of your kitchen cupboard on the surface?  Very unlikely.  Chances are you’ll just irritate your skin even more.

Of course there is the placebo effect to consider.  Doing something, anything, rather than just dancing around yelping in pain will probably make you feel better.  And rubbing your skin usually makes minor injuries hurt a bit less.  But chemically?  Nah.

So in short, if you get stung it’s probably more effective to reach for the paracetamol rather than the condiments.