SESIM’s Uma Amérika STEM program, High School Presentation #8

For our final presentations, the university students showed the science groups the wonders of natural indicators while the mathematics groups wove palm leaves into shapes with unique angles they then analyzed.

The process for the indicator activity started with preparation of 6 common plant materials: red onions, turmeric, purple sweet potatoes, banana flower, and two kinds of decorative flowers.  Each of these was reduced to a pulp with a grater and/or an improvised mortar and pestle: a cup and a wooden stick.




After that a bit of alcohol was added, the solids were strained out, and a sort of tea was made from the material. This was the indicator.  Each of 6 groups prepared one of the indicators, and then introduced it into 5 different solutions with different pH: tap water, vinegar, dilute battery acid, soapy water and lime water.


The range of colors that resulted was astonishing. One by one the groups showed their colors to their colleagues, and then set them in order on a table in front. IMG_8544


Left to right the columns are soapy water, lime water, tap water, vinegar and battery acid.  Top to bottom the indicators are banana flower, red onion, turmeric, purple sweet potato, and the two flowers.  Among other things, it was fascinating how some indicators showed yellow for base, and some showed yellow for acid.

The mathematics groups concentrated hard to get the base move down for the simple weave.  There are really only a couple of motions, but each time they must be done just right.




After everyone was on the right track, we got out the protractors and had them measure the angles they were making.  Amazingly enough, nearly all the angles turned out to be 60 or 120 degrees.




It turns out this particular weave is in some of the most common baskets the Timorese use on a daily basis, and the angles almost all follow this same pattern.  Just the idea that the baskets that Grandma makes have a load of mathematics within them can be inspiring and empowering.  We certainly saw the students take a great interest.

Next week we’ll meet one last time to prepare for the expositions, during which the high school students will present to their colleagues, with the university students backing them up. It should be exciting!


SESIM’s Uma Amérika STEM program, High School Presentation #7

At our second to last presentations, the topics were not our most photogenic, and my colleagues’ photography skills are still under development.

Mathematics groups used a set of seemingly mystical number tables to divine a random number someone had chosen.  Far from magical, it was the powers of two again, and the concept is that every number can be built using a unique set of the powers of two.  It’s an interesting introduction to the base-2 number system that computers use.






Science groups studied transport and transpiration in plants.  They grabbed the leaves they had bagged the week before and analyzed the water in the bags.





The considerable water that had collected in the bags – sometimes more than 50ml – was evidence of the process of transpiration, water coming up from the ground and out the stomata of the leaves.  So then we looked for evidence of this inner-plant plumbing system, and found it in various local plants, both decorative and food crops.  I’m afraid we compromised the flower beds of the schools we were at, but it’s still the rainy season, so I’m sure the flowers will bounce back. When we put them into the colored water, within minutes we found the colored water had moved up the stalk through tiny tubes called xylem.






(Check out the students’ art/science work on the walls of that classroom at 4 Setembro high school.  It’s mitosis and meiosis modeled with construction paper, colored yarn and bits of plastic.  Well done, 4 Setembro teachers!)

Next week is the last of our presentations, and after that, the expositions!  Stay tuned!

SESIM’s Uma Amérika STEM program, High School Presentation #6

Big news:  The U.S. Ambassador to the Democratic Republic of Timor-Leste, Ms. Kathleen M. Fitzpatrick, visited our program at Finantil High School.  The school’s vice director was there to receive her, and she gave a short speech in Tetun that encouraged the students, especially the girls, to apply themselves to learning in the STEM fields. She took a few questions and then observed as our program proceeded as usual.  It was an excellent opportunity for the students to talk to a U.S. representative, and for her to have a first hand look at the program the U.S. Embassy is supporting at this local public high school




This sixth session brought the science sections back to the motor projects, a topic dear to my heart, having written a book entirely about projects with a hobby motor. It was one of the more complex activities, with many more materials and tools than normal.  Success was found in all 5 schools and the high school students learned what there is to learn from making small circuits to power little motors and cause interesting things to happen: airplanes fly around in circles, a hanging string forms into waves, and a container of water turns to a whirlpool.






A video of the planes built at Canossa high school is here.

Meanwhile on the mathematics side, they were exploring the towers of Hanoi: 3 stacks of disks, of which a larger can never be on top of a smaller, and which can only be moved one by one.  First order of business was building them. IMG_8159


Next was to figure out the progression for moving the disks according to the strange rules.



And finally, the data was taken for how many steps it takes to move a tower with a given number of disks.  The resulting formula is quite closely related to the powers of 2.


Before we left, we had the high school students tie plastic bags around tree and bush leaves to see what happens in preparation for next week’s biology activity.


SESIM’s Uma Amérika STEM program, High School Presentation #5

At this presentation we were halfway through our list of topics, so we switched groups of high school students. The ones who had been doing mathematics pratika now began doing science, and vice versa.  By the end each group will have done four of each, and they’ll present all 16 activities to their peers in our exposition events in April.

This week mathematics played the hopscotch-like game in which the opponents hop around to take squares and gain points.  The progress of each player can be graphed in a simple line graph, in addition to being listed in a table.  The value of the data table and the graph is made apparent through this activity, and the students get a chance to practice generating and manipulating data.  They also get to PLAY!








You can tell from that last graph being made at 4 Setembro high school that the players were way out of practice: the kids on my street can wrap up a game with half that many moves!

In science, models of the sun – earth – moon system were constructed and used to understand basic phenomena like day and night, eclipses, phases of the moon, and seasons.  First the construction, based on a hard plastic soccer ball widely available here as the earth, a ping-pong ball as the moon, and a cheap but focusable headlamp as the sun.




Then the fun began as students tried to create the phenomena with the models.  The size ratio was pretty close to reality – earth/moon = 4/1 – but the distance was much too close.  Still, it’s possible to mimic each of the phenomena.  Each group then demonstrated what it had found out to the other groups, with the university students stepping in to clear things up when necessary.







Outside at my school, An-nur, a martial arts class was going on.  It was great to see the little girls in headscarves happily punching away at each other.



SESIM’s Uma Amérika STEM program, High School Presentation #4

This week’s presentation had the science group doing electro-chemistry with a simple electrolysis activity and the mathematics group exploring the wonders of pentaminos.  For some reason, our cameras and phones were not working so well, so many of the photos came out marginal, but the smiles still come shining through.

Pentaminos are the 12 possible non-congruent shapes that can be generated by  sticking together 5 squares.  This is a great little puzzle to work out if you ever have a bit of time and some scissors.  First you cut out a bunch of squares and then you see what the possible ways to hook them together would be.  Then you cut out solid pieces in those forms and see what other shapes you can generate with the pentaminos.




It’s possible to put them together to form perfect rectangles of 6 x 10 and 4 x 15 among others.  It’s a real challenge, using the mathematics of patterns and counting possibilities. Some of our schools have those silly one arm desk-chairs, so the students ended up working on the floor.  You can witness the success anytime you note a full rectangle.




Electrolysis is the stuff of science fiction: ripping water molecules apart with an electrical current.  But if you use common solutions of water and low voltage, it’s perfectly harmless.  We tried 3 different electrodes – copper, zinc and aluminum – and 3 different electrolytes – salt, vinegar and soap – and noted the different quantity of bubbles generated at each side of the circuit as well as the different precipitates.








Only one or two of the schools got to the point of collecting the gases being generated and attempting to burn them;  it’s too long of an activity.  But just witnessing the gases and solids resulting from the electro-chemical reaction among liquid solutions was fascinating enough for the students.  Our goal is easily achieved:  these students are thrilled with the opportunity to do anything hands-on or real, which leads one to believe there is not much of this at all in their normal classwork.

SESIM’s Uma Amérika STEM program, High School Presentation #3

The third round of high school presentations involved compressed air paper rockets and measuring distant dimensions using similar triangles.  I’ve chosen photos from 3 of the high schools, An-nur, 12 November, and Canossa.  Our university facilitators are usually identifiable as the ones not in uniform.  Feast your eyes.

First, the height measurement.  As you may recall, if you know two sides of one similar triangle and one side of the other, using a proportion you can find the fourth.  This comes in handy to measure the height of something you can’t quite reach (or something you can reach, so you can check the result!). So you hold up a ruler at arm’s length and note the size of the distant object and you have the small triangle formed.  Then you measure the distance to the object.  Finally, you measure the distant object, to compare to your calculated result.









After you get all these measurements, you put them into the proportion to see how close the calculated result was to the result that you measured directly.





Each group in the science section constructed two compressed air rockets with a single factor changed between the two:  length of the body, number of fins, weight (a rock for payload or no payload), etc. They made predictions as to the effect of these various factors on the height and distance of the rocket’s path.





Then they launched the rockets at a constant angle with 40 psi of pressure from our homemade launchers. (No people or animals were injured, though some rockets did blow up on the launch pad.)






There you have it: the next generation looking to the sky with goals and aspirations and a keen interest in science and mathematics.

SESIM’s Uma Amérika STEM program, High School Presentation #2

The topics for the second presentation were body systems models, and the mathematics of calendars, including magic squares.  Again, the number of photos from 5 schools was a bit overwhelming, so I’ll just choose a few that show the engagement and eagerness of our students, university and high school alike. All in all, we coordinators are extremely pleased with the results.

The mathematics of calendars was a bit subtle, but the students were really into it.  The most basic thing they learned was how to express numbers in an algebraic manner.  For example, if the date of Tuesday is x, then next Tuesday will be x+7, and next Thursday will be x+9. Last Tuesday will be x-7.




Interesting things happen also when you add up numbers on the rows, columns and diagonals of square grids in the calendar with 3, 4 or 5 numbers on a side: you often find all the sums are the same.  These are called magic squares and it’s fascinating to find them right in the midst of a normal calendar month.



The body models were 3: respiratory and circulatory systems, urinary/excretory system and the digestive system.  Two groups at each school constructed a model of each on a large piece of paper from a pile of colorful rubbish.




When they finished, they presented to each other what they understood about the function of each organ.  Finally, the university students stepped in to add information and clarify.






After each session with the high school students, we coordinators debrief with the university students and give them suggestions on how to improve their technique.  It’s good to see them really listening to us, and it’s nice to notice improvement the next week. Our plan to hone their pedagogy is truly coming to fruition.