Making 3D Printers

Kerrby Day 1 image

Teaching technology has been a blast at Fairhaven Middle School this year. A little coding (we used to call it “programming”), a little 3D design and printing, a little trebuchet and mousetrap car design and building.

I was excited that in the first semester we almost tripled the number of printing hours on the MakerBot 3D printer in the classroom. I have had to order 5 rolls of filament so far (if I recall correctly.) In any case I have not been able to keep up with student demand for 3D printed products.

When visiting the Seamonsters Robotics club at our local high school I saw some home-made 3D printers chugging along making parts for their competition robots. Sehome practical engineering teacher, Kevin Criez, told me they were designed by a local engineer. I found that our local makerspace (Bellingham Foundry) has been working in conjunction with a retired mechanical engineer, Jeff Kerr to produce these printer kits. For $350.00, you get all the parts and free advice and coaching from Jeff and other makerspace enthusiasts and space at The Foundry to assemble your printer.

I have been working on “my” two printers for two evenings so far. Frankly? This has been some of the best fun I have had in ages. I get to build my own 3D printers! Then they go into my classroom and kids will have access to printing on their own. We’ll have a battery of 3 printers (1 Makerbot Replicator II and 2 Kerrby’s – as Jeff’s printers are being called). My goal is to make the design and printing even more accessible by kids.

Right now I receive their files (made in Sketchup) and I export them to .STL format (using a free Sketchup extension). Then Makerbot prints directly from those files. I would like to stop being a bottleneck and have a “PrintMaster” in each class. A student whom I teach to use the printer and respects the technology who can coach other students to preparing and setting up their designs for printing.

This is getting such an enthusiastic response from students that we probably need some kind of after-school time for students to make designs and get them printed.

In the meantime, I am enjoying this at least as much as the students are!



Food Science

tea pic

After a morning of grading I needed to get away from the screen for a few minutes. So I went to McDonalds where I could get a coffee, soft drink or tea for a dollar. Being close to lunch I needed more volume and wanted more sweetness than a coffee so I got a tea. They have, as you can see in the picture, both sweetened and unsweetened tea.

I have purchased sweetened tea in the past, but it is SO sweet that I can’t drink it straight. So I usually get a “half sweetened; half unsweetened” tea. It must happen a lot because when I go to the drive-through the cashier often has a special term for it, calling it something like: “One large ice tea; cut.” In any case, this time I was making the tea myself.

Now the problem with this tea is that it does not naturally mix. Recalling some demonstrations as a science teacher, the sweetened tea should be significantly denser than the unsweetened tea. The question arises then; should I put in sugared tea, then unsugared? or vice versa? Or should I add a little of one; a little of the other; a little of the first, and so on until my cup is full? Which sequence is likely to cause the best “mix.”

If I put in the sugared (denser) tea first, it will sit on the bottom while the unsweetened (less dense) tea sits on top. The result will be that the tea will be introduced to the cup in layers that will not spontaneously mix. I will have to mechanically mix them to produce a homogeneous solution. That is, I will have to stir the tea with a spoon or shake the cup. This is not a significant effort, but  I hope to find a way to do it without mechanical agitation.

If I add the less dense fluid then it will be on the bottom when the denser solution is added to the cup. The result, I think, is that the denser tea will “fall” through a less dense tea, even as the less dense tea, which is more buoyant, rises. This will produce a modest convection that will mix the tea to some degree.

As an anecdotal conclusion, based on my perception rather than objective, measurable data, I can tell you this method is satisfactory: add the low density tea (unsweetened) then the high density tea (sweetened.)

I also make sure the tea squirts into the cup along its circular, inside surface -as I add both teas – so that a modest vortex does, in full disclosure, provide some degree of mechanical mixing, making the tea as heterogeneous as possible.

A Downside of Security

WP login screen.PNG

Since my last post in Malaysia, I have been unable to return and edit this blog. Ok; full disclosure: I forgot my password. That is no big deal. Unless you have taken pains to make your site secure. This blog was made “more secure” by a secondary verification protocol. If I forgot my password, say the instructions, verification over the phone, by text, would protect me.

Protect me from myself what was I did not foresee. When I moved to Seattle in summer 2014, I did not have access to my Malaysian phone number. So all those, “I forgot my password” buttons that I punched, took me to a window which assured me that my code, sent via SMS would let me log in. Off course, WordPress sent those codes to Malaysia. I, however, was trying to access my blog from Seattle. “Two roads diverged [on the information highway]…”

But today I was able to chat a WordPress Happiness Engineer and she “engineered” happiness for me! After several strategies (thinking of alternatives is indeed a skill of the 21st century) she got back into my account. I can’t thank her enough!

I’m home!



Bentley’s Car

jay and Bentley It is probably no surprise that we chose a widely recognized car brand as the name for my son’s car: “Bentley.” Cub Scouts has this event every year and this year Bentley wanted to do the event again. One of the challenges in these events that require a lot of parent involvement is how much should a parent do and what should the child do?

This year I took a page from my science teaching mentor, Chuck Caley from Toledo, Washington. As a new teacher Chuck ran the Science Olympiad program at Toledo after school. He did all kinds of amazing engineering events. Watching him, as a new teacher, I thought he contributed too much to kids’ projects. Mentally I chided him, thinking that his sons would learn more if he did less. It took me several years to learn that my master teacher was right and I was wrong.

When children are given complex tasks to do they often see the objective as insurmountable. A good teacher will scale the task for students so they can achieve a piece at a time. A great teacher will scale the task as well as provide some modeling for students. Chuck was a great teacher (he retired June, 2013.) He did a lot of work with kids and, when they were out of ideas, did a lot of work for kids. But the results speak for themselves. Chuck’s two sons went into computer science. The first went into programming (if I recall correctly) and the second was applying for graduate studies in robotics the last time I talked to them.

These days I do as much as is needed to help capture Bentley’s interest. With the car I cut out the pieces, then we painted it: he painted it. The paint was accidentally an oil based paint that took 2 weeks to dry. After that we used an acrylic spray paint (grey as you can see above.) I painted it for him and he sanded it between coats. I did not know how much this was appropriate, but one day a couple friends came over and I noticed Bentley took them both out on the porch and showed them how he was sanding his car to make it very smooth.

That was a heart squeezer! He did not have the skills and ability to cut out the car on the band saw or to use spray paint to make a smooth coat, but he COULD sand; and he took that task to heart.  I was so proud of him and based on that I saw that we hit the sweet spot on this project.

The day of the race I still had not put the wheels on. I had a plan, but I was ruminating on it and a bit afraid of the risk until, at the 11th hour, I had no choice but to get it done. These wood blanks for Pinewood derby cars have a groove in the bottom for the nail-axles. The problem with that design is that a bit of a knock, like a child dropping a car, causes the axle to mis-align and then the car does not work properly. We had that problem last year.

I decided to bore new axle holes. I think this is against the strict pinewood derby rules, but our program here permits more latitude. So I bored new axle holes about 1/4 inch above out outside the original axle grooves. I used a drill press and got them situated exactly right.

This proved to be an excellent idea. 10 minutes after going to the derby with his car, Bentley runs breathless into my office calling, “Dad! Dad!” Somehow his car had been damaged and one axle was SO bent that the wheel was tight against the side of the car and would not roll. Thankfully our engineered axle holes saved the day! I popped out the bent nail-axle, grabbed a new nail-axle and pounded it back into the hole. Since the holes are drilled, they were still perfectly aligned. So perfectly aligned, that with a little graphite lubricant and weighting it right to the 142 g maximum mass (141.7 g technically) with hot glue and washers, we created a winning vehicle. The winning-est vehicle that afternoon with a streak of wins and no losses. Wow! He even beat cars in dens ahead of him (the Webelos).


Motivated by Their Interests

JessesshoesAbove: Angela listens to Jess’s suggestion for how to build the sole of their compression-heating shoe while Yeorin looks for a possible shoe style.

One of the fun things about giving students choice is seeing the ideas they generate out of their own experience and interests. Currently students in physical science are designing “a device which is designed to gain heat for a purpose (like cooking) or designed to lose heat for a purpose (like air conditioning).  The projects should address three methods of energy transfer: conduction, radiation and convection.

Here, three 9th graders discuss their shoe design. This is a project about “heat transfer” so these three girls came up with an idea of making a shoe that keeps your feet warm.

At this point in the discussion, Angela, Yeorin and Jess (pictured above) have decided to use compressing air as their heating method. When you walk in their invented shoes, the action of stepping on the heel will compress air in a chamber and transfer the compressed air to the forefoot. This build up of compressed air is warmer and this heat will be transferred to the bottom of your foot by conduction through a conductive material. They will line the upper shoe with a reflective material so the heat does not radiate from the foot.

The range of products can be invented or explanatory. Some inventions include:

  • cooling underwear for male athletes,
  • a suit that uses body heat to generate electricity,
  • an oven that bakes cookies on the hood of your car when you drive to work (or home).
  • a gun that shoots cooling rays (still a design in progress)
  • the “un-microwave” that uses wave energy to cool instead of heat.

Some inventions are not plausible; some are plausible just not invented. Having the opportunity to learn something they “need” to learn while doing something they want to do sure seems to be a motivating mode. It is a pleasure to see them so constructively engaged!

Boys, of course, have other interests. Joel, Sam and Daniel are designing a cooling system for Boba Fett, the bounty hunter in Star Wars (see the computer image on Joel’s computer screen in image below). Since he wears solid armor on his upper body, he will need a method for staying cool under all that hot metal. If George Lucas wants to get in touch with me I can share the boys’ design with him so Boba does not overheat in his next action-packed episode!

bobo fett

Playing Games in Class

Solubility Game Pic

I work with an amazing colleague named Roby Yeung who also teaches science at Dalat International School (see his website at <>. He has brought a lot of vigor to our science department this year. One thing he is doing in his classes is introducing games and projects tailored to the content. In biology he invented a macromolecule game in which the goal is to build macromolecules. The game is a card game and requires an understanding of bonds and different monomers, etc. I have not played the game but visited his class and saw the kids playing the game about 4 weeks ago.

In my current unit in chemistry (“Reactions in Aqueous Solutions”) one of the things kids have to do is to memorize the solubility rules. I use the cleanest-cut set of rules I could find anywhere which are both rationale and comprehensible at <>, a chemistry teaching site made by a former chemistry teacher. But memorizing is hardly interesting and so I wondered if I could put it into game format. I think I have succeeded!

The Solubility Game rules are posted here on a Google Document. Instructions for how to make the cards are also posted on the same document. It worked pretty well! Students in my class spent one homework assignment making cards. (I just had them cut 4×6 index cards into eighths as cards). Then the next day I introduced my newly fabricated rules and set student to the game.

Like any game the hardest part is getting the rules down; this game is no different, except that the goal is actually learning the solubility rules (which are part of the rules on page 2.) In the game you have two piles of cards, anions (negative charged ions) and cations (positively charged ions.) You start with 6 cards (3 of each charge) and your goal is to form ionic compounds, using one cation and one anion, and “meld,” or play your ionic compound down on the table. If the compound is soluble you earn 5 points and if the compound is insoluble you earn 10 points. In addition there are points for using polyatomic ions; more polyatomic ions in one compound eanrs more points. You also gain points for making insoluble compounds soluble – and the bonus of picking up insoluble ions so you can, in turn, play an insoluble ion down and earn the bonus 10 points for yourself.

I plan to submit this game to NSTA’s Science Teacher magazine letting teacher’s copy the game as long as they do not earn money from it (reserving the rights to commerce.) Last time I invented an ion building activity I later found a virtual copy of the idea in the same journal! I guess more than one person can have the same idea at the same time!

This is exciting. I love games; having rules and guidelines and goals make me more interested in achieving a goal. I am on the hunt now to make more games. Since I teach chemistry and physical science this year, most of the games will be in that vein. Watch here to see more ideas posted in the future.


New Stuff: Invent to Learn

There are many times we may say “thrilled,” but not as many times that we experience a true thrill. Seeing a Twitter link to a new book i had never heard about before called “Invent to Learn” was an honest thrill!
I DO think the author's should have contacted me to borrow the title of my fallow website “Build Understanding” instead of the more awkward “Invent to Learn,” but then maybe i predict their thesis incorrectly (i have only read the first 5 pages so far). But what i have read puts me on excited pins and needles.
I started my own hacking (small “h”) website in about 2007 while teaching alongside a masterful science teaching artist at Toledo High School in Washington, to fulfill a professional development (PD) requirement for teaching in my state of Washington. It would have more constructive to simply watch my colleague (designer, Science Olympiad guru and Maker 'par excellance:' Chuck Caley) and spend time being mentored by him. (One of the sillinesses of the age of “accountability” in education is that rich opportunities like building things together or talking or watching or sharing coffee in the workshop are not easily measured and so you have to sit in meetings or take “official” college courses in order to “demonstrate authentic growth…” Blah, blah, blah
I was permitted to design my own 8 hour PD and wanted to have a more organized curriculum for the 9th graders in my Physical Science class. Nicely, i could teach whatever i wanted since the curriculum consisted of nothing more than a textbook (“What do i teach?” “Huh? Well i guess just use the textbook…”). But my Western Washington University teacher training (1998) drilled in the fact that teaching is an art in which the text may play little role.
My first year i knew how do labs and write lab reports since i had studied science. I was articulate and clever, but since a person only knows what they have seen, and since i had been taught by many well organized and caring teachers but never – until a solo artist in college: Dr. Ernest Kroeker – by a master teacher, my perspective was painfully limited. I wondered how to keep the kids, and myself from mental dessication by using a committee developed textbook rich in factoids but devoid of narrative and substance.
A coarse, newsprint flyer from a wanna-be teacher support, entrepreneur named Ron who called his stuff TOP Science (didn't they all?) was stuffed in my staff mail slot with all the other weekly junk. Still, sitting on the potty was boring so i grabbed the lot and leafed through it in the quiet of a toilet stall. The sample science activities Ron showed looked very doable, and did not require me to buy expensive equipment (other than string and wooden clothespins.) i ordered a book then another and another; $9.99 each, topically organized.
Ron saved my students by providing meaningful activity designed to lead learners to understand. How much more exciting to tinker, then find tou have a question: why?
  • Why does pulling suddenly on the string break it but pulling slowly does not?
  • Why does simply running a string around a couple wheels make require less force to lift?
  • Why does a plastic bag in a jar stay “stuck” to the inside so stringly when you are pulling it out?

I was seduced by watching kids engage with building electric switches from clothespins. Wouldn't premade switches be easier? … Then i realized “easier” was not motivating, but problem solving and constructing seemed inherently engaging. I started adding construction projects as the capstone of each unit.

MEASUREMENT – Students built 3D “recognizable objrcts” using cylinders, cones, spheres, rectangular prisms and calculated the volume and surface area of the finished product.
ENERGY – Student built Rube Goldberg machines on a concept pliagerized from Science Olympiad (where it is called “Mission Possible”) and were graded on number and kind of energy transfers.
MACHINES – It is a rite of childhood to build a catapult, i thought, until i discovered trebuchets! Students shoot at a target and are assesed on accuracy.
So, seeing “Invent to Learn” excites me that an increasing number of teachers and learners and talking about the value and worth of tinkering and making as an educational activity.
I needed this. After a few years in the trenches with supervisors that alternately loved and dreaded “Jay's projects” i am infused with renewed passion to teach my students by helping them learn through doing what they love: making silly, fun and crazy contraptions!
Thanks Sylvia and Gary! and Ron Marson and Chuck Caley and Brian Brewster (who is my current principle and who is on the “kids seem so engaged and seem to learn so much by building cool stuff!” end of the spectrum. In fact it is Brian's bridge, built as an example to his physics students, pictured in the masthead of this blog.)


Density Columns

Density column


Usually I start out physical science with something kids love: fire. I think kids should have as much fun as possible as nothing is so amazing as fire – even in the lab. I’m not the only one to think this is a great idea, according to Gever Tulley’s TED talk. To fit something fun like fire into grade 9, I have begun with a unit titled “Heat” or, on the curriculum guide, “Introduction to Kinetic Theory.” Doesn’t “Fire” sound better?

Anyway, principles of conduction and insulation are fun, when they include fire, but are abstract and can be tough to learn. I use great, engaging materials from learning guru Ron Marson’s “TOP Science.” but abstract concepts are still at the horizon of many 9th graders abilities.

So this year I took a page from my principal’s science book, and decided to open the year with a unit in “Density.” Buoyancy is abstract but density is less so. We started by building paper shapes out of 1 cm cubes. Kids are given a 2D drawing of a 3D cubic shape projected on the screen. Then they cut a flat shape out of their 1 cm grid paper and fold it into the desired shape. First we build cubes of different volumes, then simple rectangular prisms (boxes) and then more complex shapes. 

At the conclusion of the unit I love to have students build a capstone construction. In this unit, I wanted them to build something that reflected an understanding of “density.” I came up with a “Density Column” whose specifications are listed here. Kids did a great job! A number earned full credit (100%) according to the rubric. And I love the objective grading: number of layers and number of buoyancies. 

In the image above the 4 fluids of different densities is clear. Many students used alcohol as the least dense and honey as the most dense. It was popular too to use a battery or a stone as a solid object denser than the densest fluid and to use styrofoam or a ping-pong ball as the least dense. What I liked in the image at top was there a solid object (a wooden chess pawn) which has a density making it “float” inside the golden layer above the bottom-most layer.

I think “making stuff” teaches the maker many things and is intrinsically motivating, learning activity.