I used to work with Tritium, and they were very keen to stop us smuggling out any warhead components concealed in our body chemistry. Actually, there was a risk, because tritium tended to replace hydrogen in organic compounds, so, though it was not that radioactive, it could get into your DNA and other places where it would do the most harm on decaying. So we had to wee into these big 1-litre ‘party severn’ bottles, that some poor sod on health physics had to boil down to as little as possible, and then measure.
The cure for tritium intake is beer. You can drink a lot of it. Every pint flushes out some of the tritium. You could do it with water, but most people can’t drink as much.
There was never the same fuss about deuterium. Maybe we get more of that as background.
See @SheiffFatman 's response to my post above as an example of why physics teachers tend not to stay long in the job. Physics is about trying not to tell lies, but people want convenience and simplicity rather than the truth.
Again a pedantic nitpick; it does the damage immediately after decaying, when the little bastard atom hanging off one of the carbons in your DNA decides it wants to be 3He and squirts out an electron and an antineutrino. You now have an exposed bond looking for something to hold onto, and an ionising track through your DNA to provide some suitable radicals. Doubleplusungood.
I remember once reading an article about the possibility of a universe without the weak force. No elements beyond iron and no radioactivity. Has anybody written an SF story on those lines? Good news: no nuclear ICBMs. Bad news: a lot of medical technology wouldn’t be possible.
ok, trying out an idea i’ve been batting around a little…
our conscious perception of positive qualities (in this case, ‘sweetness’) as relative to more abstract qualities of the subject (‘heavy water’). our perceptions are our perceptions, but there are physical realities that our bodies and the outside world both depend on.
for example, heavy water has 10% more mass for the same number of molecules (or at least, the same volume). that quality that gives rise to other qualities like it’s rate of dissociation, which gives rise to it’s relative acidity, …
in as generally as i can think, it can be said that heavy water has greater structure / less entropy than regular H2O. since time and space are recognized as being the same (thanks physics!), we can say that mass/structure is a greater distance (time or space) from the origin of the universe (‘the big bang’)
i see a similar dynamic in drugs that cross the blood-brain barrier. the relatively sudden increased mass of the central nervous system is a pleasurable experience
simple sugar would seem to buck the trend, but then i start thinking about about tesselation and how space is filled. giving your body lots of little carbohydrates makes it easy to fit them all in you, again allowing for greater density intake. like packing a car full of basketballs vs golf balls. the golf balls leave less empty space.
any of this recognizable to anyone else out there?
You are assuming far too much. No one said anything about comparing the weights of equal masses because we aren’t stupid. We are comparing equal quantities. The SI unit for quantity of a substance is the mole. Water weighs about 18 g/mol, D2O weighs about 20 g/mol, a difference of about 10%. QED. Yes, I know grams are a unit of mass not weight. I don’t care and unless you can tell me your weight in Newtons or slugs without a unit conversion chart neither do you Stop looking for excuses to be an insufferable pedant unless you can out-pedant everyone in the room.
Poot. I wrote that, didn’t I? I meant ‘on decaying’ of course. It does tend to preferentially substitute - I dimly remember something about the ‘aldol’ condensation - but that is harmful only when it decays.
Thanks. I will go and edit the original. I don’t want to look silly or nothin’…
I remembered it being two litres. But I looked at a bottle of fizzy water, and 2 liters seemed enormous, so I knocked it down to one. Maybe it was two. It was over half a life ago (insert lambda pun here).
It’s one of those occasions when zero point energy is relevant.
The bonding in D20 and H2O is exactly the same the nucleus is not important in forming bonds just the electrons.
But because of the larger mass of D the D-O bond has a lower zero point energy and so is much more difficult to break.
So it’s this that is the potential problem - difficult to break O-D and C-D bonds that would be formed if you managed to drink enough heavy water.
I’ve also been led to believe that heavy ice sinkd in normal water (i’ve been meaning to try it).
You can be offended if you like. I was making the point that teaching physics is hard because children (and adults) usually prefer simple explanations or phraseology, and the job of the physics teacher is to tell them that the simple explanations of natural phenomena are not, in fact, correct. Perhaps a few percent of kids are excited by this and go on to be engineers, scientists and mathematicians; too many of the rest go on to distrust and disbelieve experts.
I get the sense that the feeling of the meeting is against me and shall leave, clutching the remains of my tattered dignity.
Stop looking for excuses to be an insufferable pedant unless you can out-pedant everyone in the room.