dex, using Facebook Live to broadcast his breakdown over thermodynamics in the library: the ideal gas law is A LIE!!!!!! NO GAS OPERATES UNDER IDEAL CONDITIONS!!!! ENTHALPY IS ALWAYS INCREASING!!!!
nursey, in the comments: lmao u wild wya tho?
Normally one speaks of living things as beings that consume energy to survive and proliferate. This is of course not correct; energy is conserved, and cannot be consumed. Living beings intercept entropy flows; they use low-entropy sources of energy and emit high entropy forms of the same energy (body heat).
Can we burn information as fuel? Consider a really frugal digital memory tape, with one atom used to store each bit:
The position of a single ideal gas atom denotes a bit. If it is in the top half of a partitioned box, the bit is one, otherwise it is zero. The side walls of the box are pistons, which can be used to set, reset, or extract energy from the stored bits. The numbers above the boxes are not a part of the tape, they just denote what bit is stored in a given position.
The tape is a series of boxes, with each box containing one ideal gas atom. The box is split into two equal pieces by a removable central partition. If the atom is in the top half of the box, the tape reads one; if it is in the bottom half the tape reads zero. The side walls are frictionless pistons that may be used to push the atom around. If we know the atom position in the n-th box, we can move the other side wall in, remove the partition, and gradually retract the piston to its original position destroying our information about where the atom is, but extracting useful work.
Extracting energy from a known bit is a three-step process: compress the empty half of the box, remove the partition, and retract the piston and extract PdV work out of the ideal gas atom. (One may then restore the partition to return to an equivalent, but more ignorant, state.) In the process, one loses one bit of information (which side of the the partition is occupied).
A memory tape can therefore be used to power an engine. If the engine knows or can guess the sequence written on the tape, it can extract useful work in exchange for losing that information.
Today I realized that the method I used for studying all my life was completely wrong and because of this, I failed Aerodynamics and Compressible flow. What I did was review the concepts in the lecture notes, and then after knowing I had a grasp of them, redo the problems in my lecture notes, text book examples, and HW problems. It sounded like a decent plan, right?
Except one thing: engineering and upper-level math exams rely on students solving problems they likely never seen before. They rely on testing the “on-the-fly” problem solving skills of students. That’s why professors make tests completely different from HW and lectures.
What I was doing was reviewing what I already knew. In other words, I wasn’t actually learning anything new or teaching myself how to tackle new problems: all I was doing was pointlessly redoing all the problems.
All that did was give me a false sense of confidence without actually learning anything new. In other words, this method only made me overconfident.
A different method would be something like this (under read more)
Hey again! I’m sitting in the children section of the library, so I decided that kids running around in a room would be a good way to visualize the ideal gas equation. Hope this helped you :D Stay tuned for part two, where I explain how to solve problems concerning the ideal gas law.
Remember the main difference between real gases and an ideal gas is that there are no intermolecular forces in an ideal gas - meaning there is no liquid phase when you cool it down. A real gas is similar to an ideal gas under high temperature and low pressure. :D
P.S. Lately I’ve started receiving a lot of requests, but unfortunately I do not have time to draw them all at once - so I’m only going to draw the ones that are most requested, I’m really sorry!
title of this post comes from the statistician George Box, and discusses how
the mathematical models we use to analyse and predict the world cannot, by
their nature as an understandable simplification, provide an exact model of the
world. That is to say, they are “wrong”. However, the errors can be small
enough that we can use the models to make predictions that hold up in real
life, such as how much weight a bridge can carry. That’s where the “useful”
part comes in. A good example of this is the ideal gas law. No actual gas
follows this law, but under certain conditions, their behaviour is close enough
that it doesn’t matter.
An important thing to understand is you can have multiple models to describe
the same thing. There are a vast array of different climate models, for
instance, and while they broadly agree with each other there are important
differences in the details. Some of these are due to limitations on computing
power and time available, some are focused on certain aspects such as aerosol
production, and some are simply using a new method of modelling the world. When
we are dealing with subjects as complex as human sexuality or the climate, we
need to simplify them somewhat to allow us to grasp, if not the whole concept,
as much of it as we can. All of these models will lose some important details,
hence why they are all wrong, but some retain enough of the information that we
can use them to understand the world.
Quite a few other statisticians have issues with this aphorism, but that’s not
what I want to talk about here. I want to talk about gender and sexuality, and
how we think about them. A common comment, when we look back at history
and retroactively apply certain traits and sexualities to them, is that they
wouldn’t have chosen those terms because their internal models are entirely
different. Parts of Greece and Rome, for instance, are said to have defined the
roles in male-male sexual encounters in terms of who is being penetrated and
who is doing the penetration. Nowadays we would define both partners as
homosexual, but they used a different model to understand their interactions
than we do now. Different people at different times, different places and in
different circumstances will use different models Someone using a different
model of sexuality and gender to you is not inherently bad, or a judgement on
you. I say not inherently because there are absolutely models that fail that
include various points. I’m going to use asexuality here as an example because
that’s my own experiences, but I think the general points could be modified
slightly and applied to most sexualities.
Incomplete models, that is, ones that cannot handle the idea of someone not
being attracted to anyone, fall into two catagories. The first is the
“innocently” incomplete model; it is not that the person disbelieves in
asexuality, but rather the idea that there is a gap in their empirical model of
reality just hasn’t occurred to them. Contrast this to what we might call the
“active” incompleteness model, where the model actively denies the existence of
asexuality. I’ve encountered both of these kinds of incomplete model, as I
suspect a lot of people have, and while the models are superficially similar
how they react to the addition of an asexual person, or at least a person who
claims they are asexual like myself. I put the “claims to be” part in there not
as a way of throwing suspicion onto myself, but rather to acknowledge that
people will claim I am lying or mistaken, that it is not possible to not be
attracted to someone (you can insert “attracted to your own gender”, “attracted
to more than one gender” or any other phrase you like there). Both models are
wrong in the same way but the second model has a built in mechanism to avoid
expanding the model to take into account an aspect of reality it had been
The other thing about models is that, once you get beyond a certain point,
adding more detail doesn’t help unless you are using a model for a particular
purpose that takes that detail into account. The various terms and models of
sexuality that we classify as being on the asexual and/or aromantic spectrums
are important if you are in a situation that requires the distinction to be
made. Usually this means you are, or are interacting with, someone under that
umbrella or wish to compare the model to your own experiences to see if you
might be under that umbrella yourself. For most people most of the time, adding
this detail just adds more mental computing power, and it is enough to
acknowledge that, yes, you might need to increase the resolution on your model
when dealing with that particular area, just like a meteorologist looking at
one particular region will increase that resolution, but for now your model is
wrong, but useful in that it acknowledges the existence of the asexual
A really good example of this
is the romantic/sexual attraction divide. This is a really important
distinction in the ace community, between romantic asexuals and aromantic
asexuals, and it is also useful for people outside of it (for example, there
are bisexuals who are only romantically attracted to one gender), but is
useless if your romantic and your sexual attractions line up. It can even muddy
the waters by introducing an alleyway that might not lead you to a helpful
option. That being said, the mere fact that such a model is not useful to
everyone does not make it useless, merely that we need to shift our discussions
about such models from “this is how the world works” to “here are mental tools
to help understand the world and your place in it, and here are some possible
limitations to them”.
I think gender is even more complicated to model than sexuality just because
frankly I think the boundaries we have set on our concept of gender are
incredibly fuzzy. The less well defined something is, the more difficult it is
to model accurately, and we are really bad at defining gender. I think the
three main models are as follows: biological gender, which states that
someone’s gender is predetermined by their biology, usually chromosomes or
genitals, social gender, in which gender is defined by the range of social
expectations allowed with in it, and individual gender, in which gender is a
property of each individual, that must be defined by each individual and social
gender dynamics grow out of these definitions and their statistical
distribution. Notably I have listed this in increasing order of immediate
complexity. Biological gender claims to be less an explanatory model and more
an empirical observation; these are the two types of people. I’m not fond of it
for a couple of reasons. Firstly it doesn’t actually position the information
in a new or useful way; it is merely a description of biological factors, and
the distribution curves for what it tries to predict are large enough and
include enough other factors that breaking it down this way doesn’t add
anything. Secondly, it fails to account for intersex and non-binary people. The
two ways it handles these are either to ignore them as edge cases, which works
up until you need to include them as part of the model, or to outright deny
their existence, which again, reduces the model’s effectiveness at describing
reality. To make matters worse for this mode, it isn’t actually a particularly useful
model day to day; when choosing what pronouns to apply to someone (a process
that in itself is a conceptual model; there are languages with only one,
non-gendered third person pronoun), you don’t ask for a karyotype test result
or compared genitalia, but rather make the assumption from visible signifiers
which don’t inherently match the biological sex.
The second one, social gender
can be useful in examining social mechanisms and constructs, but in doing so
creates a lot more edge cases. Now it isn’t just intersex and non-binary people
that must be accounted for, but gender non-confirming people who, by
definition, are edge cases in the model. The social model of gender becomes
particularly dangerous, rather than simply incomplete to an alarming degree,
when it becomes prescriptive instead of descriptive. To paraphrase a certain
first century carpenter “The model was made for the people, the people were not
made for the model”.
The final model, the
individual model, essentially simply increases the resolution as high as it can
go, and relies on people’s internal definition of gender. Full disclosure; I am
agendered, so I don’t actually understand what it means to have a particular
gender, but some people I know have very clear internal definitions. Some of
these are based on physical sex or social norms; I think there’s quite a few
cisgendered people who lack an internal definition like myself, but don’t have
a reason to use a definition other than the biological one. We could call this
being cis by default. Other definitions of gender are highly idiosyncratic, and
to be honest I think this is inevitable just because, like I said above, the
initial parameters that we are trying to model are really badly defined. What
do we mean by gender? What weighting do we put onto different aspects of it? And
that’s before we get into the question of working out the mechanisms that give
rise to it; untangling biological and social influences is difficult enough
given we can’t isolate and raise babies in a controlled lab because ethics is a
thing and is important. As such, I think the best way to proceed is to find
your own model, but acknowledge that it is not universal and accept other
people’s own models of their gender. It’s unsatisfying, but at this point, what
else can we do?
Just wanted to send out a little note - a friendly reminder - that if you have any troubles in a chemistry course or chemistry related topic feel free to send me a message. While my studyblr is here for personal motivation to finish up my undergrad, it’s also here as a resource for anyone who struggles or needs some simple help in chemistry. So far I have taken both general chemistries which cover topics ranging from unit conversions, titrations, ideal gas laws, molecular geometry, and intermolecular forces, *The list continues and I have multiple study/cheat sheets for many of these topics since my lecture was student-based teaching. Also, I have completed the first semester of organic chemistry that includes resonance structures, chirality, nomenclature, SN1/2 and E1/2 reactions, and alcohol synthesis. Right now I am enrolled in the second semester of organic chemistry (currently making a solid B in case you wanted to know how reliable I am with my knowledge) and have covered ether synthesis, aromatic nucleophilic/electrophilic substitution, activation/deactivation on the aromatic ring, amine synthesis, aldehyde/keytone synthesis, carboxylic synthesis. Next semester I will begin advance organic structure studies that include UV spectrum, proton and carbon 13 NMR, mass spectrum, and IR spectrum. Though I am already confident with handling those instruments and can help anyone who needs an understanding of how to label peaks or knowing what an unknown compound contains. On top of that, I will be taking analytical chemistry next semester as well.
Of course, the list continues because I willalways try my best to answer any chemistry related questions that my followers have. (Google does wonders for me and I have a good way of finding amazing study guides) So please don’t be shy when asking questions or correcting me when I’m wrong. I don’t have my degree yet in chemistry so I’m not always correct! :) Love you guys and keep up the good work. [Link to my ask box]
*It would be awesome if everyone could spread this little note so I can help anyone out who needs it. I hate to see students struggle in chemistry when I am currently on my way to becoming a teacher.
The expectation value can be well understood by studying the mathematics applied to particular scenarios. In this post we will apply a quantum mechanic approach to find the expectation value of measurement.