Teacher’s Corner: Retarded!

As you may know by now I have recently started a new job as a special ed teacher without having actually trained as a special ed teacher. This is pretty challenging on top of the job being challenging anyway, and I’m trying to desperately read up on the concepts and theories of the discipline. In doing so I stumbled across a word that is one of the nastier ones flung around in English: retarded.

And I discovered that it is a good word. Or at least used to be.

See, special ed went through it’s development just like regular teaching. Concepts and ideas about children, learning and teaching have changed, change which is often (though not always) reflected in our schools. In its earlier stages, special ed saw children who were slow to learn as “defective”. Children who could more or less keep up with the classwork were “normal” and the other ones were broken, damaged goods, lacking. You see where this is going.

Then came science and studied children and how they learn. They put many things educators had long known on a scientific basis and formulated scientific concepts. One of the still most influential people in this area is the Swiss psychologist Jean Piaget, who described the processes through which we learn and also formulated stages through which we develop.

Screenshot of Piaget bok covers

Yes, there’s an endless amount of books on and by Piaget

All legitimate criticism aside (it relates mostly to how far you can take his models and where are limits of their application), his models are still important. As teachers we want and we need to challenge our students to help them in that development, which isn’t an automatism. We need to construct our input at the right level. Primary school teachers will endlessly use concrete things and pictures to teach their students. They need to literally take away five marbles to find out what 12-5 is.

What especially Piaget’s students found out was that not all children develop at roughly the same pace. Some children are much slower than the average, they stay behind, they are “retarded”. The concept as such was revolutionary. The children were no longer seen as defective, just slower. They were not inferior to their peers but would reach the same levels of cognitive development as their peers, just later. This had, and has, great importance for teaching children with special needs, as it means that we need to give them different input, teach them using a much more hands on approach than with their peers and most importantly, get them to the same place, just a little more slowly.

It’s sad to see how ableist ideas turned such a revolutionary concept into a nasty slur. It also shows that you need to change society, not just words. The slur does not mean what the word means in a professional context. It still means “broken and defective”.


Anatomy Atlas Part 21 – Heart

Heart. An organ whose importance was known throughout the history, but whose real function was not.

©Charly, all rights reserved. Click for full size.

The one interesting fact about heart that springs to my mind is that one of the most important discoveries into how it actualy functions was done by a Czech anatomist Jan Evangelista Purkyně who discovered the specialized impluse-conveying neurons in 1837 (but I had to look that date up, since I have terrible memory for numbers). They bear his name “Purkynje fibers”.

I wonder whether kids in other nations around the world get to hear his name when learning about heart.

Anatomy Atlas Part 19 – Torso Muscles

Compared to the back, muscles on the front of the torso are relatively well-known even to laypeople. Prominent pectoral muscles and the famed “six-pack” are shown-off in comic books, movies, advertisements etcetera ad nauseam.

©Charly, all rights reserved. Click for full size.

However Professor Kos had nothing interesting to say about any of the muscles shown here, except the musculus platysma, which is not on the torso but on the neck.

It is a thin sheet muscle, directly under the skin to which it is connected with fascia. In humans it is a muscle of relatively minor importance, nearly a vestigial organ. But vestigial of what? According to Professor Kos, its function can be really well observed in horses and cattle. These animals use their tails and ears to try to keep flies and mosquitoes at least somewhat at bay, however they cannot effectively reach their necks and parts of torso. However what they can do, and do (I have in fact observed this myself) they can flex their  musculus platysma and similar thin muscle sheets directly under the skin, thus giving their skin a mighty shake in some places that can scare some insects off.

It is a nice story, but I doubt that this is original purpose of this muscle and its equivalents somewhere else on the body. More likely it is its repurposing for another function. Who knows?

Anatomy Atlas Part 18 – Arm Muscles

I mentioned that hands are a marvel – and so are arms. However the muscle structure is a bit weird.

©Charly, all rights reserved. Click for full size.

If you have ever wondered why biceps are called biceps, now you have the answer. The musculus biceps brachii splits into two parts on the upper end  and each is attached to a different part of the shoulder-blade. Whilst it its the most prominent muscle and its development is seen as a sign of strength, biceps is not the strongest flexor in the arm. That is in fact musculus brachialis which lies underneath, connects to ulna it and generally is not seen very much.

Professor Kos mentioned that this arrangement of these two muscles leads to one peculiar thing – flexing of the arm can exert more force when done palm up, than when palm down. Why? Because when the palm is directed down, the musculus biceps has its load bearing tendon wound around the radius to which it is connected. Therefore it cannot flex without also trying to turn the hand palm up.

So when lifting things by flexing your arm palm-down, only two muscles – m. brachialis and m. brachioradialis – can exert force, whereas palm up the m. biceps can join for more strength.

Why is it like this I do not know, but had it been designed, the engineer would deserve at least a pay cut.

Reconstructing the fearsome Haast’s eagle.

A comparison of the huge claws of Haast's eagle with those of its close relative the Hieraaetus morphnoides, the "little" eagle. Image / Bunce M, Szulkin M, Lerner HRL, Barnes I, Shapiro B, et al.

A comparison of the huge claws of Haast’s eagle with those of its close relative the Hieraaetus morphnoides, the “little” eagle. Image / Bunce M, Szulkin M, Lerner HRL, Barnes I, Shapiro B, et al.

With a wingspan reaching as wide as 3m and huge claws that could crush bone, the Haast’s eagle was one of the most fearsome creatures ever to stalk New Zealand’s prehistoric wilderness.

The largest eagle known to have existed anywhere, its demise quickly followed that of its much-larger prey, the moa, which was hunted to extinction by early Maori settlers around 1400 CE.

Now a top international scientist and Kiwi collaborators hope to shed more light on the lost giant, in an innovative study that could help conserve those endangered predatory birds that remain today.

An artist's depiction of a Haast's eagle attacking two moa. Image / John Megahan.

An artist’s depiction of a Haast’s eagle attacking two moa. Image / John Megahan.

You can read more here, thanks to David for letting me know about this.

Flowers of the Sky.

Depictions spanning almost a whole millennium – in chronological order – of comets, meteors, meteorites and shooting stars. (My choices here aren’t in order!)

Leonid Meteor Storm, as seen over North America on the night of November 12-13, 1833, from E. Weiß’s Bilderatlas der Sternenwelt (1888) – Source.

Leonid Meteor Storm, as seen over North America on the night of November 12-13, 1833, from E. Weiß’s Bilderatlas der Sternenwelt (1888) – Source.

Astronomy: a meteor shower in the night sky. Mezzotint, after 1783 – Source.

Astronomy: a meteor shower in the night sky. Mezzotint, after 1783 – Source.

Augsburger Wunderzeichenbuch, Folio 52 (erschrocklicher Comet, 1300) – Source

Augsburger Wunderzeichenbuch, Folio 52 (erschrocklicher Comet, 1300) – Source.

You can see many more wonderful depictions at The Public Domain Review.

Making a Rondel Dagger – Interlude 2 – Measuring the Hardness

I am not done with the “Behind the Iron Curtain” series, but right now my mind is way too focused on other things.

One such thing was the conundrum of measuring hardness of steel. There is no way I can spend thousands of € on measuring equipment. And the cheapest “sort of” evaluation of hardness is a set of five needle files that costs over 200,-€. I would rather spend that money on materials, but I do not mind spending a few hours of work.

So yesterday I had my first shot at this issue.

First thing I have done was to find in my scrap pile old and damaged hack saw blade. I have heated it piecemeal with handheld propane torch to orange heat and quenched it in a bucket of water. Since it is uniform thickness, the water does cause no cracking this way and quenches the steel very nicely and without flames or stink.

After quenching each segment I broke it off (it breaks really easy) and proceeded further, untill there was no unhardened steel left. After that I broke all the pieces into much smaller pieces until I had a nice little pile of extra hard steel shards.

These I have dunked straightaway in a pot with about 1 cm of sunflower seed oil and proceeded to my kitchen. There I was heating the oil very slowly to temper the steel whilst measuring the temperature with my IR thermometer. The higher the temperature, the lower the steel hardness, so I had  temperature steps predefined at which I took a few pieces of steel out of the oil bath.

For that I have found this site on the Interwebs that was kind enough to post a table of  hardness versus tempering temperature with not only the silly units the USA uses but also the sensible units the civilised world uses¹, so I could actually understand what temperature ranges we are talking about. I wrote the temperatures from the table on pieces of paper and put them into small receptacles in which I have placed the tempered shards. I did try to hold the temperatures for about 15 minutes, but for a steel this thin that is not completely necessary.

At 260°C I stopped, because after that the oil could ignite, and I made the remaining temperatures on a fireclay brick with handheld torch. For these soft rangers I do not need much precision anyways.

With all the shards tempered and hardened I have cut ten pieces of hardwood from old spokes from my crib.  They are a bit too thick, but I had no wooden dowels of the right thickness in my pile and I did not want to use wood set aside for arrows. I cut a groove in each piece and marked the pieces 1 to 10 with roman numerals (because those are easy to carve with a knife).

After that I glued one shard in each groove with fast healing epoxy. The softest one in the I and the hardest one in X. Once the epoxy has healed, all that was left was to sharpen the shards on my belt grinder and I was done.

I have tried whether the hardness progresses from I to X and it does. 10 is able to scratch everything, I scratches nothing, and each higher number seems to scratch the one below but not the one above. Here they are (one is missing in the picture, I do not know why, how typical of me to miss-lay things in a matter of seconds).

I measured the dagger on the tang where it is hardened but will not be visible later on. VIII scratched, VII almost scratched, VI did not scratch at all. The hardness should be therefore somewhere around 58 HRC. That is hard enough to keep an edge, but not so hard as to shatter or break easily or eat sharpening stones.

As a proof of concept I would call it a definitive success. I have a set of tools that allows me to estimate the hardness of steel from about 40 to 65 HRC. Not with great precision, but well enough to be useful. After I get my hands on some suitable high carbon steel (about 1% is needed) of thickness about 2-3 mm, I will make better ones, chisel-like, with not only a tip to scratch, but also an area to be scratched.

A little backyard scientist project.

1 – I hate that USA insists on using the silly units and infests half the internet with that nonsense. Finding well written articles on the internet that are not in English is difficult and when something is written in English, it is often US-centric. As if USA did not spread enough misery as it is, it has to keep poisoning sciences and engineering with this utter garbage.

Amsterdam: Below The Surface.

Peter N. sent this amazing project to me, and it’s absolutely fascinating!

In Amsterdam there’s a public works project going on which has involved draining a river. Archaeologists have been able to search through many feet of sediment for artifacts – which date back 800 years. There’s a wonderful website which describes the project in detail here: https://belowthesurface.amsterdam/en/pagina/de-opgravingen-index

… and one of the pages is a catalog of over 11,000 finds, with beautiful photos and descriptions, arranged in chronological order: https://belowthesurface.amsterdam/en/vondsten

It just thrills me to think that every single one of those objects comes with a story, which, unfortunately, is lost forever – a lovers’ quarrel, a picnic, a flood, a missed arrow shot…

I feel the same way  as Peter. Seeing small pieces of history always makes me wonder about all the people and their lives. Peter chose one particular piece for me, and was spot on, I love it!

I’m going to be spending some time gawking at all the amazing things found in this streambed archaeology!

Song Ci: The Washing Away of All Wrongs.

Nomenclature of human bones in Sòng Cí: Xǐ-yuān lù jí-zhèng, edited by Ruǎn Qíxīn (1843).

Nomenclature of human bones in Sòng Cí: Xǐ-yuān lù jí-zhèng, edited by Ruǎn Qíxīn (1843).

Song Ci (Sung Tz’u) is considered to be the founder of forensic science. In 1247, Song Ci wrote Collected Cases of Injustice Rectified or The Washing Away of Wrongs.

Different versions of the book exist, but the earliest existing version was published during the Yuan Dynasty, containing fifty-three chapters in five volumes. The first volume describes the imperial decree issued by Song Dynasty on the inspection of bodies and injuries. The second volume contains notes and methods on post-mortem examinations. The third, fourth, and fifth volumes detail the appearances of corpses from various causes of death and methods of treatments to certain injuries of a wounded person.

Song Ci ruled regulation about autopsy report for court, how to protect the evidence in the examining process, the reason why workers must show examination to public impartiality;how to wash dead body for examining the different reasons of death. At that time, the book had given methods to distinguish suicide or pretending suicide.

The particulars of each case must be recorded in the doctor’s own handwriting. No one else is allowed to write his autopsy report. A coroner must not avoid performing an autopsy just because he detests the stench of corpses. A coroner must refrain from sitting comfortably behind a curtain of incense that masks the stench, letting his subordinates do the autopsy unsupervised, or allowing a petty official to write his autopsy report, otherwise any potential inaccuracy is unchecked and uncorrected.”

He also said:

“Should there be any inaccuracy in an autopsy report, injustice would remain with the deceased as well as the living. A wrongful death sentence without justice may claim one or more additional lives, which would in turn result in feuds and revenges, prolonging the tragedy. In order to avoid any miscarriage of justice, the coroner must immediately examine the case personally.” [Source]

Medievalists has a list of ten observations Song Ci made when it came to discerning murder, and different types of murder.

Last year, photographer Robert Shults did a photographic series called The Washing Away of Wrongs, all taken at a forensic research facility in Texas.

Robert Shults, photograph from The Washing Away of Wrongs, with flowers from a nearby tree fallen across a donor’s body (courtesy the artist).

Robert Shults, photograph from The Washing Away of Wrongs, with flowers from a nearby tree fallen across a donor’s body (courtesy the artist).

You can read all about that, and see more too, at Hyperallergic. There are some graphic photos, so have a care.

Anatomy Atlas Part 11 – Guts

Guts. The tubes that transform delicious food into disgusting shit. Which, in turn, is delicious food to other creatures who turn it into even smaller shit. And so on until it is all recycled back into living tissue or fossilized. In nature as a whole there is no such thing as waste and if something can be digested and turned into energy to sustain life, sooner or later there will be an organism doing just that.

©Charly, all rights reserved. Click for full size.

The interesting story about guts that our esteemed Professor Kos told was quite literally about shit.

Our digestive system is not particularly effective in absorbing fats, a significant portion of excrement are lipid compounds. And this, indirectly, is responsible for the oh so typical color of the final product of human digestive system.

When red blood cells die, the heme has to be broken down in order for the iron to be re-absorbed and recycled. Some of the end products of heme recycling are two chemicals: one called bilirubin (yellow), which gets later on broken down into stercobilin (brown). This is the reason why bruises go from initially red through blue to yellow and brown color as they heal.

The same process is happening also in liver and the chemicals bilirubin and stercobilin are excreted with bile. And because they are not water-soluble but are fat-soluble, they remain in the undigested fat in feces and are responsible for their distinctive color.

No. That’s Just Wrong.

I was happily lost in The Public Domain Review the other day, and came across High Frequency Electric Currents in Medicine and Dentistry from 1910. I know there was great excitement over electricity, and there were phases of “miracle cures” where it was concerned, but in this case, it was the photos which got my attention, including one which just about had me screaming, and I’m not even a parent:

The text reads:

Plate XXII. – This beautiful picture (as exquisite as Manet’s “Boy with the Sword” which is one of the classics of the Painting Art), sets forth this boy bringing his pocket “Tesla” for the enjoyment of his beloved tonic. His sturdy strength at the age of three is a tribute to the efficacy of high frequency currents, for at the age of three days, when his treatment with them was begun, he was an illy-thriving and frail infant with but the feeblest hold on life. Look at him well, and think how many myriads of pallid children – of all ages – need the same remedy.

There is So. Much. Wrong. there, it just leaves me sputtering. Applying electrical currents to a three day old infant? All I can think is how very easily that could kill said infant. As for the photo being as exquisite as Boy with a Sword, let’s see:

L'Enfant à l'épée'' par Edouard Manet, 1861.

L’Enfant à l’épée’ par Edouard Manet, 1861.

Yeah, I don’t think there’s any honest comparison there at all. There are other questionable and frightening photos to be seen with the magical Tesla wand, but have a care, there’s some nudity, so NSFW.

S Is For Spirulina.


A while back I was involved in preparing an activity for kids as part of a science outreach event, the goal was to show them some bacterial diversity and how different bacteria look, both macroscopically (and for that we tried our best at Petri Dish Art, I highly recommend you look that up) and microscopically. As I was scanning through a wet mount of Arthrospira platensis (spirulina), I found this delightful S-shaped filament (called a trichome) and couldn’t resist. The quality isn’t very good, this was taken by hand-holding my phone over the microscope’s eyepiece.

  1. platensis is a cyanobacterium, a photosynthetic organism that gets its energy and food from sunlight and carbon dioxide just like plants do. Unlike many cyanobacteria, A. platensis does not produce toxins and that’s why it can be used as a food supplement. Its cells typically associate into spiral-shaped filaments but what you see here is a fragment of a spiral that has taken a S-like shape. If you zoom in you can see the individual cells and at the bottom right of the picture there is a single cell. No staining was done, they are naturally green because of the chlorophyll.

Click for full size!

© Nightjar, all rights reserved.

“Going to the Dogs?”, Workshop.

“Going to the Dogs” Workshop #2 brought together scholars from England, Scotland, and Poland to discuss the various and complex intersections of disability- and animal-studies research. Discussions centred on talks delivered by Rachael Gillibrand (Institute for Medieval Studies, University of Leeds), Dr Ryan Sweet (School of English, University of Leeds), Dr Andy Flack (Department of History, University of Bristol), Dr Neil Pemberton (Centre for the History of Science, Technology and Medicine, University of Manchester), and Dr Justyna Włodarczyk (Department of American Literature, University of Warsaw). The talks covered topics including the animal assistants of disabled people in the late-medieval West; nineteenth-century representations of animals with prostheses; connections between historical understandings of animals that live in darkness and vision-impaired people; the role of the caress in 1930s America human-guide-dog partnerships; and current controversies surrounding emotional-support animals in the US.

-Via Medievalists.

The full set of workshop videos.