this post was submitted on 27 Jun 2025
569 points (98.6% liked)
Science Memes
15398 readers
1982 users here now
Welcome to c/science_memes @ Mander.xyz!
A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.
Rules
- Don't throw mud. Behave like an intellectual and remember the human.
- Keep it rooted (on topic).
- No spam.
- Infographics welcome, get schooled.
This is a science community. We use the Dawkins definition of meme.
Research Committee
Other Mander Communities
Science and Research
Biology and Life Sciences
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- !reptiles and [email protected]
Physical Sciences
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
- [email protected]
Humanities and Social Sciences
Practical and Applied Sciences
- !exercise-and [email protected]
- [email protected]
- !self [email protected]
- [email protected]
- [email protected]
- [email protected]
Memes
Miscellaneous
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Fun fact: a gram of plutonium contains about 20 billion calories. Yum.
Not dietal calories.
The calorie numbers we assign to food, measure how much energy our body extracts from them when eaten.
In this context, plutonium is closer to 0
If we instead want to measure the actual total physical energy content of materia, we would turn to E=mc^2, telling us that a gram of anything has about 20 million kcal, no matter if its plutonium or diet coke. which is a slightly less useful value on food labels :D
Technically it measures how much you can heat up a known volume of water if you burn the food. We have no way of measuring how much of that energy released by combustion actually gets absorbed and translated to ATP in the body, but it’s the best estimation we have of the relative energy content of foods.
There’s some carbohydrates, proteins, and fats that our bodies don’t seem to convert to energy (or only partially convert) but still technically contain “calories” because they’re combustible. Sugar alcohols, fiber, etc.
Plutonium doesn’t combust, but it would heat up water in a calorimeter. Really the test method’s applicability kind of falls apart when you start testing undigestible materials.
Equivalent-level of fun fact: 1 gram of hay contains that much calories too!
No wonder cows are so fat
This is a commonly quoted fun fact that is not really true. There are 2 different definitions of calorie. One means the absolute amount of energy in an object, the other means the bioavailable amount of energy that a human can extract from it using their digestive system.
So every physical object that exists has some amount of potential energy contained within it which we can express in calories, but that doesn't mean it has any bioavailable calories. For example glass has some significant amount of energy contained within it, but it has 0 bioavailable calories.
This "fun fact" mixes up the two definitions, making the statement meaningless.
(Nothing against you OP, this is a commonly repeated falsehood)
Thank you for the clarification. I wanted to go along with the joke of it looking “edible”, but context is appreciated :)
Which definition does full corn kernels fall into?
And, if I have to explain the joke: it's just E=mc² (the Einstein thing ... well, the Einstein's thing's approximation), the energy (E) is the same for all mass (m) since the c is a constant.
You get the same 21 billon kcal from 1g of apples as from 1g of plutonium.
And since it's usually well known humans do not devour mass into pure energy that might trigger ppls sense of humour.
(Additionally the idea of eating metal to seek nutrition might be funny, but we do need some metals \m/.)
Also "potential energy" phrasing is weird in that context.
It's not even two definitions, the kcal is absolutely the same, it's just used to measure two different things (mass energy vs the sum of what an average human can extract via chemical processes). I see you def understand that, but it's not a different definition of a calorie (in the same way as length vs width of an object isn't a different definition of a metre).
It is a different definition, but it's the same unit... it's also more like saying "that ball of yarn is 10 metres" - the ball itself isn't 10 metres long in any dimension, but the meaning is clear given the context, as it would if you said "it's 0.05 metres". By having two meanings distinguishable by context, it seems like two definitions to me.
(Different definition/pov of what is measured, yes, that is where the joke is.)
Hehe, look at this falsehood - there is no way this things can talk!
(However imho this is a more clear example of 'two different definitions' of the main concept/phrase inferentially mixed together for comedic effect, bcs words can explicitly have more than one meaning, and yes, usually you can tell from the context.)
This pic is def:
If you eat just one bite you'll never have to eat again for the rest of your life!
And it goes straight to my hips. By which I mean the bone marrow in my pelvis.
Why the pelvis specifically? How did it get there? What were you doing with it?
These hips don't lie : you got cancer
Hey, sexy bone-marrow pelvis, shake them atomic gains!
(OK, but like, if I produced synthetic plutonium I would make the box look like a chocolate box. Those workers & engineers deserve to have a fun work environment, engage in some shenanigans, make an oopsie from time to time.)