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Comment by danieltillett | Hacker News Reader

There are an amazing number of scientific urban legends in the lab too that are passed down orally from senior to junior members. My personal favorite is that drinking MilliQ (ultra pure water) will cause the cells in your gut to explode [1]. How such a stupid idea ever got taken seriously by scientists who should know better has always amazed me.

[1] On the topic of drinking MilliQ water I have always encourage all the members of my lab to drink it. The reason why (apart from the taste which I quite like), is that it allows you to detect when you have bacterial contamination of your MilliQ carboy that will ruin your experiments.

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Based on the fact that you didn't mention doing it, I am assuming you're missing out on a brilliant opportunity for hijinks here. Suggestion - take an alka-seltzer and some red food dye (I'm not sure if you can drip food coloring directly onto an alka-seltzer slowly enough that the dye is absorbed without causing the alka-seltzer to foam up, but probably you can experiment with something like this) and hide it in your mouth ahead of time. Loudly proclaim that it's harmless to drink MilliQ. Take a big beaker of MilliQ and drink it, allowing plenty of it to reach the alka-seltzer. Pause for half a second, start to look uneasy, grab your stomach, then start allowing blood-red foam to spill out of your mouth. Fall to the ground shaking and moaning.

Bonus points if it'a "demo" you do while teaching a lab class.

Sounds like fun :)

I has a colleague who used to like putting dry ice bombs in people’s tip waste containers. You would be sitting there pipetting away and them boom - tips all over the bench.

I've heard that handling ultra pure water, can cause acid like burns due to water drawing out chemicals from the skin. I heard it from a bio PHD, and can't find any evidence googling it now.

This one is new to me - even more stupid than the drinking myth if that is even possible.

Well, it might have an element of truth. It is Hydric Acid, after all.

It is fairly well known that water will dry out the skin by leeching the oils.

(edit: and when I say element I mean microscopic element)

Actually most water is a dilute solution of carbolic acid with a pH around 5.5 because of the dissolved CO2 in the water.

This sometimes catches people out when they use pure water to store something like DNA which will breakdown over time at this pH. It is in theory why you should use a buffer like Tris/ETDA to store DNA. I have found that storing DNA for a short time in water is normally OK, but if you want to keep the DNA for more than a month it is a good idea to use a buffer.

You probably mean carbonic acid. Carbolic acid is an organic compound also known as phenol.

Yup, I heard the gut-exploding-ddH2O in a lab and a girl in the class eventually did drink a little bit of it and was absolutely fine. A science champion, if you ask me.

I have had people try to physically stop me from drinking MilliQ water as they thought I was going to die in front of them!

I have always thought it would be a good business idea to sell MilliQ branded water for human consumption. The complete lack of taste is an interesting taste in itself - the closest I can describe it as is it is like drinking liquid air.

That particular legend is way beyond the lab now:

http://www.fastcompany.com/1750612/dangerously-clean-water-u...

I love the “informed comments” on this article too. How do these people not melt when it rains?

Do you mean you detect contamination by taste? Is MilliQ that pure?

Yes you can detect contamination in MilliQ by taste. I don’t know the threshold, but I do know that if it has a taste then the water is contaminated enough to ruin your experiments.

Are the contaminants dangerous? Or just normal microbial flora that you'd get on kitchen glassware?

No they are not dangerous. Pathogens are adapted to living in nutrient rich environments (i.e. our bodies) where their problem is avoiding our immune system. The bacteria that can grow in MilliQ water are those adapted to living in low nutrient environments and these bacteria are always harmless - except that is to your experiments :)

Caulobacter vibroides

Wouldn't the very act of drinking it contaminate that source with bacteria from your lips?

I don't work in a lab, but I assume you'd pour it into a cup/beaker and drink out of that

Don't drink it directly out of the container...

I've heard people in my lab make similar claims about regular distilled water -_-. Even when I drink it in front of them they still have doubts.

Don't they sell distilled water in the supermarket? How do they figure supermarkets can get away with selling something that dangerous?

Supermarkets also sell things like salt, tobacco and alcohol which will kill you if consumed in sufficient quantity

And Hot Pockets.

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