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Posts Tagged ‘democritus’

 

Yours Truly in 3D

Yours truly in glorious 3D plastic. I modeled my head using Sculptris by Pixologic, then added the base in Daz3D Carrara. I had the printer set on the fastest speed and one shell, so the top of the base did not get covered very well.

3D printers have become all the rage in STEM classrooms. I’ve been salivating over them since they first became affordable for schools. We purchased one at Walden School just before Thanksgiving and I’ve kept it busy ever since. However, like any new technology, if I didn’t have a long-term plan for how to use it or a clear purpose in mind, it will be a new toy for a month or so and then sit idly in a corner gathering dust. They are great for someone who is willing to experiment to get print jobs to work consistently. I had quite a few failures at first, and still have them occasionally. The printers aren’t cheap and neither is the plastic. But with these caveats in mind, they can be truly useful additions to your STEM classes.

Lea - Camille with studs

Two of my MYP Design students printing out plastic snaps they designed.

I’ve taught 3D modeling classes for many years, and have incorporated 3D technologies into many of my science projects. I’ve written about several ways of doing this in previous blog posts, including the last post on modeling Greek philosophers in 3D. My students have become proficient at modeling any kind of object they need, so a 3D printer was the next logical step. Since I am teaching mostly engineering, computer science, and design classes this fall, we have need of a way for students to manufacture prototypes of their designs. For these reasons I convinced the powers that be to purchase a 3D printer.

All 3D prints

Some of the successful print jobs we’ve done so far. Most of the objects have been done as experiments to learn and test the workflow from 3D model to print.

After a lot of research, I decided to buy a Monoprice dual extruding printer – available for about $700. It came within three days of placing the order (woo-hoo!) and my IB Design Technology students had it assembled in about two minutes. Then came the process of learning how to use it to get consistently successful prints.

This isn’t as easy a process as some may think – if you have the notion that it’s like plugging in an ink jet printer and sending a print job from any software (in other words, plug and play) then you haven’t studied up enough on how these printers work.

Heraclitus failed

What happens when the model detaches from the print platform. It slid aside but continued to print, leaving the “spaghetti brains” hanging under the top of his head. The grid on the bottom is the raft. It also created scaffolding under the beard, which has been removed.

The process is called additive manufacturing and involves creating an object by extruding a thin plastic filament onto a flat print platform. The platform moves slowly downward (z-axis) as the extruder moves sideways and in and out (x and y-axes) to build one layer at a time. Think of using a hot glue gun to build up a contour map of a landform. For this all to happen, the 3D object must be split into layers by the printer’s software and a pathway generated for the extruding nozzle so that it lays down the filament without it getting tangled or dripping. This pathway/layer split is referred to as g-code.

Tyrian Purple 2

A model of a molecule of Tyrian Purple dye. This dye was extracted in the Phoenician city of Tyre on the coast of Palestine by crushing the shells of murex sea snails. One snail would produce only a drop of the dye. It was so expensive only the Roman nobility could afford to wear clothing dyed with this color, hence the phrase “born to the purple.” It is my favorite molecule. The large atoms on each end are bromine, which provides the burgundy/purple color.

 

To get the 3D model into a form that can be split into g-code, it must be saved or converted into an STL format. There are online converters for doing this. Of course, even before that, you have to know how to make the 3D objects in the first place unless you are content to simply print out someone else’s models, such as those found on Thingiverse or at the NASA 3D website. In that case, you aren’t realizing the potential of this device for modeling, engineering, and prototyping of student-created projects.

Sarah portrait

Student self-portrait. The head and hair were done in Sculptris, the base and text in Carrara. It then was exported as a 3DS file and converted to STL, then loaded in ReplicatorG to generate the g-code layers.

If this process sounds complicated, it is. But that’s not the half of it. If your models have overhanging parts, the printer will just create a lot of plastic “boogers” (see the failed print of Heraclitus and the “brains” hanging out of his disconnected skull to see what I mean). So the software creates supports or scaffolds to hold up the overhangs, which must then be removed and sanded down. The software also creates a raft or grid of plastic underneath the model to help it stick to the print plate. That is the grid you see under the failed Heraclitus.

Black plastic objects

Our printer allows objects to be printed with two colors at once. I haven’t attempted that yet, but here are some objects with black plastic. The D is part of my family’s cattle brand, the Lazy Bar D ranch.

There are many problems that can occur. If you print large, flat objects with square corners, then the plastic can cool too quickly with both sides exposed and the corners can peel up and curl. Although the print platforms are usually covered with a tacky tape such as Kaptan, you can still have print jobs come loose and start sliding around as the extruder nozzle moves. This is what happened with the failed Heraclitus – it did well up to his eyebrows, but the continued wiggling of the nozzle head caused the raft to break loose, so the printer continued the job off to the side as the model slid away in stages. Kind of cool looking, but the print wasted eight hours and some plastic. Now I have to start it over again and tape it down better.

Democritus and Aristotle prints

Printouts of Democritus and Aristotle. To provide better quality for the print, I created a sloped base with rounded edges to prevent curling. Both models were created using Make Human for the heads, then imported into Sculptris to add the hair, beards, and eyebrows. Finally, the models were brought into Carrara to add the bases and text before exporting as a 3DS file.

I have also had an issue with the workflow itself. To make Heraclitus (and Democritus and Aristotle) I started with a free program called Make Human, which allows one to set morph targets on a generic human figure to make the features look a particular way. I loaded in photos of the philosophers to use as referents. Then I exported the model as an OBJ and imported it into Sculptris, another free program done by Pixologic, the same company that does the leading character modeler Z-Brush. It works like a ball of clay that you push and pull into shape. I used it to add the hair, beards, and eyebrows. Then I exported it again as an OBJ and imported it into my full 3D modeler, called Carrara by Daz3D (but you could use Maya or Blender, etc.). In Carrara, I decapitated the head from the body using a Boolean command, then added the base and letters. I finally exported it as a 3DS model, converted it to STL using Online 3D Converter, then loaded it into the ReplicatorG software for generating the g-code. By the time I was done, this model had been through five different software packages.

Cow parts and snaps

Some student design projects printed out. The cow parts (head, legs, and tail) on the right are for a toy cow. The body of the cow had some issues printing, and the C-joints on the legs didn’t quite fit. The snaps on the left worked with the smallest positive size and the split hole configuration. The MYP Design students planned, created, modeled, and tested these prints. Now they need to make revisions. This is the engineering process.

This is a complicated process, and the model can fail anywhere along the way. I’ve had some trouble getting Carrara to export the models correctly – it says they are there, but have no data in them. I think these are models that have too many polygons, such as those where the entire head and hair are done from Sculptris. Using Make Human keeps the head model’s polygon count reasonable.

Mare Fecund printouts

Two printouts of Mare Fecunditatis on the Moon. I started with LOLA data from the Lunar Recon Orbiter mission, loaded it into Adobe Photoshop in Raw format, selected the section I wanted and loaded it into Daz3D Bryce as a grayscale height map, which turned it into a terrain object. I exported it as a 3DS file, added the base and letters in Carrara, and so on. The print on left was done at fastest print speed and didn’t fill in well. The one on right has two shells and reduced print speed, but still lacks detail. My next attempt will be at a 45° angle with supports underneath to gain the better resolution of the x and y-axes.

I’ve tried making 3D terrains of Mars and the Moon based on Mars Global Surveyor MOLA and Lunar Reconnaissance Orbiter LOLA data. I load the grayscale heightmaps into Bryce (another Daz3D program), then export a 3DS file into Carrara to build a base and text. The final results have had issues with holes in the bottoms of craters, text that doesn’t show up well, and insufficient vertical exaggeration to see any details. I also had trouble with the first attempt to print this terrain (of Mare Fecunditatis on the Moon) because I only had one shell and had the printer on fastest nozzle extrusion speed and travel rate, so the top was not solid enough.

 

But . . . with all these problems, I am succeeding now more often than failing. That is what engineering is all about, after all – you have to learn how to fail until you succeed. I’ve tried a variety of different print jobs, found out the trouble spots and (mostly) how to correct for them, and I am ready to start printing out student projects now that we are approaching the end of the semester.

Hackathon 3D 4

Students learning 3D modeling using Sculptris at the Utah County Hackathon on Dec. 12, 2015, sponsored by 4-H.

 

 

On Saturday, Dec. 12, 2015, I presented a session at the Utah County Hackathon sponsored by the local 4-H Club. I took the 3D printer along as well as some laptop computers from my school and taught about 24 kids how to use Sculptris and how to do 3D printing. The session was a great success. There was a man named Colby there who had quite a bit of experience with 3D printing. He gave some advice that I will try out soon: First, I can get better resolution by standing my terrain models on their side. These printers have better resolution in x and y-axes than in the vertical z-axis. I just need to build some buttress supports to hold it up that can be removed later. He suggested using PEI (polyetherimide) tape, which becomes tacky when heated on the print platform, then less sticky when cool, so jobs won’t slip while printing but still come off cleanly when cooled down. He gave me some ideas for better temperature settings – I might have my platform temperature too high. There are still many experiments to try.

Hackathon studs and printer

3D printer and students learning Sculptris at the Utah County Hackathon, Dec. 12, 2015.

So, to summarize the lessons learned:
1.) Don’t expect a 3D printer to work perfectly right out of the box. There are a lot of tweaks to do, including calibration, print platform leveling, temperature adjustment, feedrate adjustment, etc, etc. to do before you will be consistently successful. Read up on the forums and ask lots of questions before deciding which printer to buy, and be prepared to experiment.
2.) Unless you are content with printing pre-created models, you should be ready to teach (or facilitate) your students learning how to do 3D modeling in the first place, and how to convert their models into the STL format needed for 3D printing. There are many fairly easy to learn 3D programs out there, including Sculptris, Sketch-Up, Tinkercad, and Make Human. Maya is also free for students and teachers, but the learning curve is steep. Blender is open source and free, but the interface is hard to learn even for experienced modelers.

Hackathon 3D 2

Students learning Sculptris at the Utah County Hackathon on Dec. 12, 2015. They are building alien heads. They enjoyed learning the program and seeing how to do 3D printing.

3.) Try to get a printer with a heated print platform and variable temperatures and extrusion rates. One size does not fit all jobs here, especially if you want to print with more than one type of plastic. ABS expands more when heated than PLA plastic, so it tends to curl more as it cools down. It also requires a higher nozzle temperature to melt it.

4.) Keep an eye on print jobs. My failed Heraclitus started out well, so I taped the edges and left it overnight to print. Somewhere around six hours into the job, it detached from the print plate and caused the fatal print defects shown. Print jobs also sometimes stop for no reason. You won’t be able to start them up from where they left off. It will just be wasted plastic. You must keep trying, and be patient.

Electroneg and Tyrian purple

Final printout of the Tyrian purple molecule. The black model is of the periodic table of elements, showing the property of electronegativity for each element. This was done by typing the values into a TXT file, then importing it into ImageJ software using Import-Text Image, then converting the grayscale image into a height map for Daz3D Bryce. From there, we used the same process as the 3D Moon models.

5.) Have a plan and a purpose for why you need a 3D printer. Otherwise they can be frustrating and ultimately unsatisfactory for you. If you haven’t integrated 3D data analysis or modeling into your classes already then a 3D printer will be useless for you. If you want some ideas how to do this, look at some of my other posts, such as this one on creating 3D models of periodic properties of the elements: https://elementsunearthed.com/2014/05/10/visualizing-periodic-properties-of-the-elements/ . Here is a photo of a 3D print job done from one such model, showing electronegativity, as well as a model of the molecule for Tyrian Purple dye.

6.) Some supplemental materials will help. Buy some Aqua Net Super Hold odorless hair spray (purple can) and spray it onto a paper towel, then rub it onto the tape on the print platform to improve the stickiness. Even with that, the jobs might still work loose. Some people use glue sticks or a gel adhesive. You will need a roll of Kaptan or PEI or blue painters tape to put on the platform if the tape starts to peel up.

Indi portrait

Student self-portrait using Sculptris and Carrara.

7.) Avoid large flat objects with sharp corners. They tend to curl up when cooling. If you build in supports, you can print up to a 45° angle without scaffolding, and therefore take advantage of the better resolution of the x and y-axes.

Good luck. Let me know what types of projects you attempt, and we can swap ideas. As you can see from the photos here, there are many possibilities for chemistry classes alone.

Hackathon 3D 1

Students working with modeling clay to learn the concept of 3D modeling. This is at the Utah County Hackathon on Dec. 12, 2015 at the Provo Library. The image on the screen is of the ReplicatorG software. It is printing my family’s cattle brand, the Lazy Bar D. Unfortunately, the bar wasn’t quite level with the bottom of the D in Carrara, so a raft wasn’t printed under it and it went at bit wobbly and timey-wimey.

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A 3D model of the Temple of Artemis at Ephesus, where Heraclitus lived. This image was modeled by Cameron Larson.

A 3D model of the Temple of Artemis at Ephesus, where Heraclitus lived. This image was modeled by Cameron Larson.

During the summer of 2009, I fulfilled a research fellowship at the Chemical Heritage Foundation in Philadelphia. I’ve previously written about my experiences there in this blog. One of the major areas I researched was the history of Greek philosophies regarding matter, fundamental materials, and the nature of reality. I wrote a script and created various animations to use for a three-part video about the philosophers and their theories. Over the next year, in between working on other projects, I recorded narration and put together timeline sequences in my video software for the three segments. But there the project stalled out, because all I had was my own voice talking with B-roll footage over the top. It was too boring, even for me. I needed to interview an expert to provide primary footage, using my narration only to stitch it all together. But I was back in Utah by then with no available experts around that I knew of.

3D model of Aristotle created using Make Human for the head, Sculptris for the hair and beard, and Bryce for the final render.

3D model of Aristotle created using Make Human for the head, Sculptris for the hair and beard, and Bryce for the final render.

During the summer of 2014, I fulfilled a Research Experience for Teachers in astronomy at Brigham Young University, as I have described in my other blog (http://spacedoutclass.com). While talking with Dr. Eric Hintz, my research advisor, he mentioned a paper he had written with a BYU philosophy professor named Daniel Graham. It regarded a Greek philosopher named Aristarchus, who calculated the size of the Moon based on the extent of a solar eclipse. I realized that I had found my expert literally right in my back yard.

I e-mailed Dr. Graham and he consented to talk with me, and we spent a fascinating 90 minutes discussing the various Greek matter theories and philosophers. He agreed to allow my students and I to videotape him answering our questions, and even gave me a book he had edited on the philosophies of the pre-Socratics.

3D image of Empedocles. Of course, we have no idea what they really looked like.

3D image of Empedocles. Of course, we have no idea what they really looked like.

In my next post, I’ll describe this interview and provide a transcript. Before he came to our school, my students needed to prepare for his interview. I introduced the Greek matter theories as the first of the three threads that led to modern chemistry (I’ve written about these threads before at this post: https://elementsunearthed.com/2009/07/31/three-threads-to-chemistry/ ). Students were assigned individual philosophers and asked to become familiar with their lives and theories, then create a series of questions that they could ask of Dr. Graham. I looked over their questions, made suggestions, and had students revise them so that they wouldn’t be redundant. I sent the list to Dr. Graham to review before his interview.

3D image of Heraclitus. He is often shown as the Weeping Philosopher, saddened by the folly and impermanence of the world.

3D image of Heraclitus. He is often shown as the Weeping Philosopher, saddened by the folly and impermanence of the world.

Meanwhile, my 3D modeling students were learning how to use basic character design software such as Sculptris by Pixologic. I had them use illustrations and sculptures of the philosophers to create torsos in 3D. We also used a new program I found called Make Human, which allowed a basic human figure to be morphed into whatever shape we wanted. The students used Make Human to create the basic head, then imported it into Sculptris to form the hair and beard around it, then took the pieces into Daz3D Bryce for final assembly, texturing, and rendering. Our purpose was to create a series of images and animations to use as B-roll in the final videos. We also hoped to add morph targets and bones and animate the heads talking through quotes of the philosophers. This would require modeling the inside of the mouths, including tongue and teeth, and wound up being too much of a challenge for my beginning 3D students.

Aristotle with a quote attributed to him.

Aristotle with a quote attributed to him.

In addition to the animated torsos, I had students use Bryce to build recreations of temples and other buildings found in the cities where the philosophers lived, such as Miletus, Abdera, Acragas, Ephesus, Athens, and Elea. We had to find diagrams or illustrations of these temples. The Temple of Artemis at Ephesus was one of the Seven Wonders of the Ancient World. Using only artists’ renditions and photos of a scale model found in Ephesus today, the students who did this temple had quite a challenge. Not all of the temples were completed, but many of them got at least the buildings done with excellent detail. It pushed our computers to the limit.

Empedocles with added Photoshop effects.

Empedocles with added Photoshop effects.

One of the many projects I’m trying to finish up this summer is to complete all these animations along with hand-drawn illustrations of the philosophers. I have a watercolor painting I did several years ago called The Elusive Atom that included many of these philosophers, and I’ve used Adobe Photoshop to isolate the philosophers from the background. I also have my pen-and-ink illustrations using homemade ink as well as homemade watercolors. I’ve gradually been building up these projects so that when I do the final editing of the video segments and include Dr. Graham’s interview footage, I will have enough materials.

I knew it would take some time to transcribe and edit the interviews, and that I would have to recreate my original animations (they were designed for SD video six years ago and I now want to do this video in HD) and revise and re-record the narrations. I wanted to start using all these materials now, so when my students created the large timeline banner on atomic theory, I made the banner cover all the history of chemistry and included many 3D images, illustrations, and photos of books from the Chemical Heritage Foundation.

Another view of Heraclitus. I set the models into Bryce, added a marble texture and skies, and created a simple camera orbit animation so that renders could be easily created from different sides.

Another view of Heraclitus. I set the models into Bryce, added a marble texture and skies, and created a simple camera orbit animation so that renders could be easily created from different sides.

I have not given up on creating a series of videos, posters, a book, and other materials for this Elements Unearthed project. My need to earn a living as a science and technology teacher has kept me too busy to do much more than write a few blog posts now and then. But I keep filling in pieces, such as the tour of Adonis Bronze I reported on in my last post, and research of other ancient art forms. I took a group of students on a tour of Nevada mining towns last year. I’m only halfway through blogging about my trip of Colorado mining towns in 2012. What I need is two years of free time and about $100,000 in grants to focus on this project, travel to the places I still need to visit (there are many), and put everything together. Have boxes of tapes I need to capture, but not enough money to purchase the hard drives needed. So if you know a rich patron who’s got money to spend on such a project, please let me know!

More Aristotle quotes.

More Aristotle quotes.

In the meantime, I’m still trying to keep this blog going despite having so much happening in other areas of my professional life. It’s been a crazy year. Mostly I’ve been involved in aerospace and STEM education activities, and I’m writing about some of them in my other blog.

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The Five Elements

The Five Elements

As I teach chemistry and astronomy again for the first time in several years, I’m having a lot of fun getting back into the physical sciences with all of the lab experiences I’d collected and developed over the years before I started teaching multimedia exclusively. I’ve also added a number of excellent activities that I picked up from my experiences with NASA and from various conferences and presentations. It’s also a lot of fun to start incorporating my expertise in media design and technology in ways I never could before, as well as the materials I collected at Chemical Heritage Foundation in 2009. For example, I just finished teaching a Keynote presentation on Greek matter theories that I put together myself using photos, drawings, illustrations, and 3D animations (mostly my own) and information collected at CHF. I have all the files stored on various hard drives that all hook into my Mac Powerbook (about four terabytes total). Some of the images I pulled off the Internet at school using our wireless router and Airport technology, and once the Keynote was finished, all I had to do was hook my laptop up to a projector and give the presentation (complete with animations and audio clips) using an infrared remote. Here’s the presentation, in Powerpoint format. If you want to use it, be my guest:

Greek_Matter_Theories

To me, all of this seems remarkable, even miraculous. And here I am writing about it on a Blog, publishing my experiences instantaneously where anyone in the world can read them, and even sharing the presentation itself. Yet I feel as if I’m only just scratching the surface of what these new technologies can do. That’s part of why I’ve been working on this Elements Unearthed project for the past several years; there are so many connections between science practitioners and students that can still be made and which I hope to develop, so many innovative methods of teaching that no one’s thought of yet. I’m a digital immigrant; my students are natives. I’m always playing catch up to what they’re already using daily.

Engraving of Democritus

Engraving of Democritus

So far this blog has been written entirely by me (David Black) since it debuted in Oct., 2008. Now that I’m teaching chemistry again I am turning over much of the posting to my students, who will be taking turns once per week adding information about the research project they are pursuing. They have chosen between an element (such as copper), a material (such as cement), a method of generating energy (such as solar power), or a time period from the history of chemistry (such as medieval European alchemy) and are compiling notes into an MS Word document with references.

With each post, they are to include about 500-800 words of writing in their own words culled from all of their research notes and include relevant images or diagrams. They are also producing a nicely laid out document such as a newsletter, poster, or brochure that will be converted to PDF format and linked to this blog for download. It may take a week or two for the first few student posts to contain these linked files, but they will come. My hope is that any chemistry teachers or students out there who are reading this blog will be able to download these linked files and use them in your own classrooms.

Plato and Aristotle

Plato and Aristotle, Detail from The School of Athens by Raphael

During second term, the students will be developing and practicing a hands-on demonstration that involves some property or aspect of their topic. We’ll present these demonstrations to the elementary classes at Walden (I’ve already met with the teachers to plan this out) and the students will also present them to each other for feedback. During third term, we’ll create a more extensive project from their topic: a detailed Powerpoint or Keynote presentation or a three-minute video or a computer game. They’ll present these in class again, then fourth term put all of this together for a back-to-school science night for the public and their parents and siblings. We’ll videotape these presentations and share them with you as well.

I’ve done all of these things before in various multimedia or chemistry classes, but this is the first time that technology and opportunity have combined to allow me to put it all together. I am still looking to build partnerships with local organizations (museums, mining associations, etc.) that will combine my students’ media skills with their content. I’ll still visit mining towns, take tours of museums, and continue to post about how technology can be used in the science classroom. I also plan on writing more grants and professional articles. I’ll continue to create longer format videos to go with the student short videos (the Tintic Mining District is up next after I make some changes to the beryllium videos).

This blog has certainly been successful in what I’ve intended it to be. Last month (September) was the best month so far with over 2700 visitors to the site. I’ve had over 23,500 visitors total, most of them this year. I would love to hear from any science teachers or students that have found this site useful.

I look forward to seeing what my students come up with as they post about their topics. I’m encouraging them to do more than just a list of properties, to dig deeper and talk about the unusual stories and histories of each element or material. And now, I am pleased to introduce my chemistry students’ blog posts . . . .

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    In this blog entry I’d like to discuss some of the ideas that I have been researching so far here at Chemical Heritage Foundation, report on a conference I attended last week, and give an overview of my plans for the next week.

Empedocles of Akragas

Empedocles of Akragas

    I’ve been conducting my research at CHF for about 2 1/2 weeks. So far I am on schedule for the topics I wish to cover while I’m here in Philadelphia. My goal for these first two weeks was to survey the theories of elements and atoms proposed by the ancient Greek philosophers, then use the third week to research how these theories were carried into the Middle Ages. I used to think that Greek scientific thought on the nature of matter could be divided into a neat dichotomy, with theories of elements (stoicheia) as proposed by Empedocles and Aristotle on one side, and theories of atoms as proposed by Democritus and Epicurus on the other. As I have dug deeper, however, I find that the issue isn’t nearly so simple. Not only did the Greeks theorize about the nature and structure of matter, they also looked at the nature of change, the origin and fate of the universe, and the underlying forces that drive it all. This creates whole sets of conceptual dichotomies. Attempting to sort through all of this while getting to know the personalities and lives of these philosophers has been a fun challenge. I can’t say I’m much of an expert yet, but I have enough to begin to put together a podcast episode on this topic, to be completed and uploaded by the end of August.

    At the risk of over-simplifying, here is what I’ve found: the Greeks were already thinking about where the universe came from and what it was made out of by the time of Thales of Miletus, around 585 B.C., who was considered one of the first philosophers (independent thinkers – “lovers of wisdom”). Thales proposed that everything was made of water, although his follower Anaximenes thought it was air. By about 500 B.C., Parmenides of Elea taught that change was an illusion, that the senses weren’t to be trusted, and that there could only be Being and Non-being. He denied the possibility of empty space (a void) saying it was a logical impossibility. His student Zeno, in a series of famous paradoxes, such as the one about Achilles and the Tortoise, showed that motion (and therefore change) was impossible.

Democritus of Abdera

Democritus of Abdera

     In contrast to the Eleatic School, Heraclitus of Ephesus taught that change was the only constant in the universe, that you can’t step in the same river twice because both you and the river have changed in between. He felt that fire, as a symbol of change, was the universal element. As a compromise between the extremes of Parmenides and Heraclitus, Empedocles of Akragas proposed that there were four elements (earth, water, air, and fire) and that although these elements were eternal and changeless, they could combine and break apart to form new materials. He felt that their were two opposing forces, what he called Love and Strife, which tried to bring the elements together or break them apart.

    Also in contrast to the Eleatic School, Leucippus of Abdera proposed that all things were made of small, indivisible, unchanging atoms which traveled in a void, combined by the forces of a primordial vortex into larger clumps of matter. His pupil, Democritus, took these ideas further and said that nothing existed except atoms and the void, and that atoms combine from necessity (he was a bit vague on what this meant). Unfortunately, most of his original works (some 70 books) are lost and we know of them only from the references of others.

Aristotle's Hylomorphism Theory

Aristotle's Hylomorphism Theory

    One of those others was Aristotle, the pupil of Plato and teacher of Alexander the Great. Aristotle tried to create a system of knowledge that tied everything together, including the material world and the heavens, and that explained the nature of change. Like his teacher Plato, he felt that there were ideal forms that created the patterns for all things, and that all things had purpose.  He taught that the primordial subtance (hyle) took on the forms (morphe) of the four pure elements, and that these elements had properties including hot and cold and wet and dry. All other materials were mixtures of these elements. By changing the properties of one material, it could be transmuted into another, such as base lead maturing into precious gold. He also felt that the elements were arranged in spherical shells with earth at the center, surrounded by water, then air, then fire. The heavy elements sank because of a force he called gravity and the lighter elements rose through a force called levity. Finally, he proposed that a fifth element (literally the “quintessence”) called ether surrounded fire and was the material from which the incorruptible heavens were made.

Aristotle and the Elemental Spheres

Aristotle and the Elemental Spheres

    Aristotle’s views were brought into harmony with the Catholic Church by the Summa Theologica of St. Thomas Aquinas. Democritus’ views on atoms were supported by Epicurus and therefore seen as too materialist and hedonistic by the church, and they fell out of favor (but never entirely died, as I’m finding out this week). It wasn’t until the Enlightenment that atomic theory began to revive.

    Now, of course, this is a very simplistic overview. I’m in the process of writing this all up in more detail, including some interesting though apocryphal stories of the philosophers, for a podcast episode of The Elements Unearthed. I’ll be presenting this information, and giving an overview of the project, at a Brown Bag Lunch next Tuesday, June 23, from 12:00 to 1:00 here at Chemical Heritage Foundation (315 Chestnut St., Philadelphia). The public is invited, so if you’re in the area, please stop by. It will be in the 6th floor conference room. I will have some samples of animations and images with narration for this new episode, as well as previous episodes created by my students at MATC and a presentation on the project as a whole.

Epicurus

Epicurus

    One final note from this last week. I had the opportunity to attend a conference entitled “Composition to Commerce: Chemistry, History, and the Wider World” held June 12-13 at CHF. It was set up as an opportunity to hear experts in the field of chemistry history present some of their current work and to discuss the historiography of chemistry; that is, how one goes about telling the history of chemistry. Although I felt myself to be a bit of an interloper, I was excited to find that some of the best experts in the field were there – people like Lawrence Principe, William Newman, Alan Rocke, Ursula Klein, and others. In my researches here I keep coming across their names. I didn’t get the chance to talk to all of them, but at least being there and seeing them lets me know who they are. I hope to enlist their aid in this project, perhaps as Subject Experts on alchemy and the history of atomic theory that I can interview later this summer. I also found the conference interesting in how various historic alchemists/early chemists were treated and how some names I’d never heard of are now surfacing as having had an important impact on the history of chemistry, such as Gassendi, Sennert, Starkey, and others. I’ll enjoy getting to know their stories as well as the those of the better known figures such as Boyle and Lavoisier.

    Anyway, wish me luck on my presentation next Tuesday. Stop in if you can. After that, I must dig into revising my application for the National Science Foundation which is due on Thursday. But more on that next week . . . .

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