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2020 March 15

Virtual science fair

Yesterday was the Santa Cruz County Science and Engineering Fair, which had been scheduled to take place at the Santa Cruz County Fairgrounds in Watsonville.

But on Monday March 9, 5 days before the fair, the entire thing was changed from an in-person event to a virtual event.  Students with projects were asked to upload a report, a video, a picture of their poster, and a picture of their lab notebook.  These were supposed to be uploaded by 7pm Friday night (giving the students rather little time to prepare).

I was the lead judge for the high-school projects, of which we had very few this year—only twelve projects had originally been submitted, and on Friday night only nine had submitted the additional material.  I watched the videos and read all the reports Friday night, so that I could do phone interviews with the students on Saturday. I also scheduled all the phone interviews for the five judges in 15-minute slots and sent e-mail to the judges arranging video conferences before and after the interview period.

The morning meeting was tried first with Google Hangouts, which failed—I could not hear any of the other judges, though they could hear me and each other.  The video quality was also poor.  I switched the meeting to Zoom (using the UCSC license) and that worked much better, though one of the judges never signed in and did not respond to email.  The judges spent most of their morning watching videos and reading reports, with interviewing starting at 11:30 a.m.

After interviewing had already started, two more projects were added, requiring me to change everybody’s interview schedules on our shared Google spreadsheet (which I messed up somewhat, as I was frantically typing in changes between phone calls).  We did not get a chance to see those videos or read the reports until after the interviewing was over, which really reduced how much we could get out of the phone interviews.

After the interviews, we had another Zoom meeting, with all the judges this time (though the one who missed the morning meeting was also a half-hour late for the afternoon one—not someone I would want to work with on a regular basis).  We quickly reached consensus on our top two projects (to send to ISEF), though it took longer to figure out the third and to decide which of the projects were good enough to advance to state-level competition (assuming that state actually does do something this year).  For the first time that I can remember, I had to urge judges to allow more projects to go forward—in previous years I’ve been having to try to hold the standards high enough that weak high-school projects were not blocking better middle-school projects from going (we have a quota of how many projects we can send, but it is not split between high-school and middle-school divisions).

The process was not as much fun as the in-person event, and there was no sharing with the public (which I see as an important part of science fair), but it went better than I expected given that we were using new software for the first time and switching to an online and phone process at the last moment.

One thing I liked was having the full reports and videos available the night before—I think that we should insist on that in future, even if we have in-person science fairs.  One thing I hated was having last-minute additions to the list—we should be stricter about deadlines in future (we had to be lenient this year, because of the last-minute addition to the requirements).  If administrators want to have a grace period, we can make the deadline for report and video submissions be Wednesday night, with an unadvertized grace period to Friday noon, but absolutely no submissions accepted after that.  We obviously couldn’t do that this year, as students weren’t even informed of the need for videos and reports until Monday.

Phone interviews are not as good as in-person ones, but the video recordings of the students’ spiels was better than having the students give the same spiel 5 times. Having ten-minute slots for the phone interviews was a little tight—fifteen-minute slots, as I had originally scheduled, would have been about right.

The zoom meeting for the judges worked as well as in-person meetings have done in the past, though that might have been because we had fewer judges (and fewer projects) than in previous years.  One thing I missed was running into old friends, many of whom I only see once a year at the science-fair judging.  I also missed being able to browse the posters in other divisions and categories.  There are usually a few good high-school projects, but a lot of times the top middle-school ones are more interesting, just because there are a lot more middle-schoolers participating. (There are about 13,000 high-school students in the county [http://www.ed-data.org/county/Santa-Cruz], so having only 11 high-school projects is really rather embarrassing.)

Overall, I’d say that from my perspective this science fair was a successful one, despite the last-minute changes forced by the COVID-19 precautions.  I’d be curious to know how well the format worked for the middle schoolers.

2013 November 11

labhacks — The $25 scrunchable scientific poster

Filed under: Science fair,Uncategorized — gasstationwithoutpumps @ 10:58
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A friend just sent me link to  labhacks — The $25 scrunchable scientific poster:

Printed on Spoonflower performance knit at 300 dpi. 36”×56”, vivid colors, no unraveling, and minimal wrinkling, even after being stuffed in a backpack. Hangs straight with about 8 pins. Print cost is $22 with $3 shipping.

The idea is to use a service intended for custom printing fabric to print posters instead.  According to the web page for Spoonflower, the fabric printing company, the material is $21.60 per yard for the designer of the pattern:

Performance Knit: $24/yard ($21.60 with designer discount)

100% polyester fabric with moisture management

  • 56″ wide printable area (142 cm)
  • 4.1 oz per square yard
  • Optic white, produced in the US
  • Appropriate for athletic apparel
  • Estimated shrinkage: 1-2%
  • Weft directional stretch is 25% maximum
  • Wash separately in cool or warm water using a gentle machine cycle. Machine dry using a low temperature setting. If required, use an iron with a light touch on a synthetic setting only. Higher iron temperatures may result in color transfer and melting of fabric.

They also warn that

Our fabrics have not been treated with fire retardant chemicals and are for this reason not suitable for use in children’s sleepwear or bedding. They are also not suitable for display purposes in public buildings unless you apply such treatment after purchase.

I don’t believe that paper scientific posters are any more flame retardant than cloth ones, though the fumes may be a little less noxious, and burning paper does not stick to things the way that molten plastics do, so cloth posters may indeed need to be treated with flame retardants for safety if you plan to display them long term. A quart spray bottle of flame retardant (enough for about 6–7 posters) costs about $15 online.

Given the awkwardness of the standard poster tubes when traveling, I can see the attraction of the cloth poster, though I worried that it might a bit bulky to pack. But a 36”×56” poster would only weigh 6.4 oz, about the same as a t-shirt (I just weighed one of my t-shirts at 189g, which is 6.7oz), so it can probably be packed in about the same space as one or two t-shirts.

The biggest downside is that printing the fabric takes 10 days, plus shipping time.  Spoonflower does have a rush-order service with next-day service and 2-day shipping, so the turnaround time could be a small as 3 days, but I did not look up how expensive the rush orders and shipping are.

According to their help page,

Acceptable file formats are JPG, PNG, GIF, TIF, SVG, AI, and EPS, and the file must be less than 40 MB. Vector files (AI, SVG, or EPS) are converted to PNG format during the upload process at a size chosen by you.

Elsewhere they warn against sending vector files (SVG, AI, and some EPS files), because the files have to be converted to raster format before printing, and there are often surprises in the conversion process (they don’t say what conversion program they use, but I know that there are often problems with Corel Draw mis-interpreting SVG files—I’ve run into that problem with both laser cutting and T-shirt stencil design).

If you are careful in your use of images, the 40MB limitation should not be too bad.  I tested converting an old poster of mine from PDF to PNG at 300dpi, and it grew from 0.6MB to 6.4MB—still well within the 40MB limit.  I did not have any photographs on that poster, though, which makes a huge difference—plots and cartoons don’t take up nearly as much memory as photographic images.

Spoonflower also warns that their color gamut is different from most monitors and printers—they use water-based dyes that don’t do large areas of saturated colors or solid black areas very well, but they use more than 4 inks, so they can get a wider color gamut than most printers.  You can get a “color map” of 1500 color swatches printed on the fabric you plan to use for the cost of a yard of fabric (about $25).  They use an RGB color space and have ICC profiles available free for how the colors come out on each of their fabrics, so you can get a decent idea of how colors would come out if you use software that has a color management engine.

The person who sent me the link to labhacks was suggesting the cloth posters for science fairs, but I’m afraid they would not work there.  Most science fairs are based on table-top displays, not wall-mounted or easel-mounted posters, so science fair posters need to be free-standing.  Although one can devise means for hanging a cloth poster in the standard, it seems more complicated to me than a foldable foam-core or cardboard display, and the rig would be just as hard to pack and carry on airplanes as the foldable board. I’ve also not found any information on the Spoonflower site about maximum length restrictions for their printing.  Can they even do the standard 6′ tall science fair poster? (probably, but they only talk about sizes up to a yard).

I don’t think that Spoonflower is going to get inundated by orders for scientific posters, but think that a few people will find the ease of packing “scrunchable” posters attractive.  If I ever decide to start traveling to conferences again, I might try it myself.

Update 2013 Nov 12:

After I posted an announcement of this blog post to researchers at work, one sent me the following ad that they had just received from another company providing fabric posters.  I guess it is a trending fad.

New Solution for Conference Posters!

Take a long flight? Now you can put your fabric crease-resistant
poster in your carry-on and say goodbye to poster tubes.

Same Day Printing and 2-Day Delivery.

check our delivery schedule or visit us now: www.postersmith.com

($15 Off Coupon Code*: SABCS2013)

The fabric poster offered by PosterSmith.com is made of 100% high-density polyethylene fibers with UV inhibitor coating. This crease-resistant fabric is light and durable and is specifically designed for high resolution printing. Because of the UV inhibitor coating, the ink of our fabric poster will last much longer than a paper poster. The printing quality of our fabric poster is better than printing on the widely-used matte paper. Your poster printed on our fabric material will resemble the feeling of printing on a glossy paper (which has tighter surface and looks brighter) but generates no glossy paper’s reflective glare. *Coupon code expire 06/30/2014

Note, even with the $15 off, PosterSmith is a lot more expensive than SpoonFlower.

2013 September 23

Science Fair Workshop

Filed under: home school,Science fair — gasstationwithoutpumps @ 20:45
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Suki Wessling, my son, and I ran science fair workshop last week for middle school and high school home-schooled students.  Our attendance was meager (one student other than our two sons).  So that the effort we put into the handout will not be wasted, I’ll put it in this blog post.  The next time I do a handout for science fair, I’ll want to add a section on doing engineering projects also, since those have a somewhat different process than the simplified version of the “scientific method” that we described.

The remainder of this post is the handout:

 

Science Fair Workshop for Parents

Why science fairs?

The science fair is a lot of work. However, it is also a very rewarding project to do with your child. Benefits include

  • Helping your child do a project that has a beginning, middle, and end. This can be very useful for children who tend to be scattered and unfocused.

  • Completing a cross-discipline project, including science, math, language arts, and public speaking.

  • Supporting your child to approach more challenging work.

  • Meeting other families who love science.

The Scientific Method

The scientific method:

  • Is the basis of science

  • Is the opposite of having a belief and finding a justification for it

  • Is not weakened when hypotheses are disproven

The steps of the scientific method are

  1. Observe

  2. Form an investigative question

  3. Read what others have written, and make competing models that explain the observation

  4. Come up with a hypothesis (a prediction that is different in the competing models, not a guess)

  5. Conduct experiments

  6. Accept or reject hypothesis

An example of the scientific method in action:

  1. Observe that a plant in the shady part of your garden didn’t grow well.

  2. Why didn’t that plant grow as well as plants you put in at the same time in the sunny part of the garden?

  3. Read about what plants need to grow, noting that different plants need different amounts of sun and water.

  4. Hypothesis: This plant needs a certain amount of sunlight per day to grow well.

  5. Plant a good number of seedlings (6–8) and subject half of them to sunny conditions, half to shady conditions. Keep a notebook of the plants’ progress, with observations and measurements.

  6. Consider whether the data support the hypothesis.

How to find a project

There are many places to look to find a good project:

  • The best projects grow out of a child’s actual interest.

  • The best projects take advantage of what children like to do (e.g., messy projects, outdoor projects, math-based projects).

  • Try out examples on a science fair project website just for ideas, then try to expand on or change them based on your child’s interests.

  • Don’t just replicate the steps of a project outlined on the web!

Tips for getting through the process

  1. Plan early: Get all the dates on your calendar, and make sure your child has enough time to do all the steps (including writing the report).

  2. Don’t bite off too much: If your child’s idea is too BIG, help him whittle it down to size. Don’t be tempted to finish it off if the child resists finishing—this is also part of the learning process.

  3. Plan to be completely done well before your school’s science fair (if you’re taking part in one).

  4. There is nothing wrong with preparation: successful kids do actually practice their spiels. However, don’t overprep your child so that she seems to be reciting something you wrote. Make sure she understands what she’s talking about and only uses words she really understands.

What do judges look for?

See more details from Kevin: http://tinyurl.com/7n8r3yv

  • Multiple replication of the experiments—generally the more the better, but 3 is usually a minimum.  More replication is generally better than more different conditions.

  • Proper controls (both positive and negative, when possible)

  • Graphical display of the results with correctly labeled axes and no chart junk

  • Correct use of units of measurement

  • Proper (simple) statistics (averages, best fit straight lines, …) High school students may add standard deviation and significance tests (chi-square or Student’s T)

  • Measuring the right thing

  • Measuring and reporting inputs as well as outputs

  • Lab notebook with detailed information recorded as the experiment is done

  • Clever use of simple equipment

  • Careful thought about how the experiment could be improved if it were to be repeated

Homeschoolers and the SC Science Fair

  • Students doing projects involving invertebrate or vertebrate animals, human subjects, recombinant DNA, tissue, pathogenic agents, or controlled substances, need to get approval from their sponsoring teacher before they begin their research. A Certificate of Compliance Form must be signed by both student and sponsoring teacher, then submitted by the registration deadline. (The detailed rules have not been published yet for this year—they will be in the “Science Fair Guide”.)

  • Put the schedule on your calendar, including the awards night.

  • If your homeschool program takes part, make sure your teacher meets the school roster deadline.

  • If you are independent or your program doesn’t take part, fill out the registration form and choose your school if it’s in the list. If not, put your private school’s name in the Other box. Submit a school roster after you register.

Winning and losing

Although it’s a competition, the SC Science Fair does a great job of making all the kids feel like they have achieved something. It’s always good to focus more on the event itself—setting up the display, talking to judges, and looking at other kids’ work—than talking about the prizes.

Resources

2013 August 30

WEST theater classes fill up fast

Filed under: home school — gasstationwithoutpumps @ 10:08
Tags: , , , ,

Today was the first day of registration for WEST Performing Arts classes, and by 9:00 a.m. one of the teen classes was already full:

WEST Ensemble Players: Inspecting Carol & Much Ado About Nothing
Day/Time: Thursdays, 6:30pm – 8:45pm
Dates: September 12 – May 15 (30 weeks; see website for details)
Location: West End Studio Theatre
THIS IS A FULL SEASON (Sept. – May) enrollment
8 Monthly payments of $120 (see website for payment schedule)

Sorry, this class is full

How, you may wonder, did that happen? Well, WEST classes usually fill up quickly, but this was a special case. Earlier in the week, there had been an e-mail sent out to families of teens who had been in the WEST Ensemble Players last year:

The fall schedule has posted online at WEST. Please note that the official start of registration is Friday, August 30th. Again this year, WEST Ensemble Players will be a small class with an expected maximum of 12 students for the fall and possibly 15 students for the spring. The students expressed a desire to stay together as a group last spring. I know lives and interests and plans change, but I would like to extend a priority registration to the students from last year’s WEST Ensemble Players classes before this class opens to the public. Please note the classes were created keeping in mind a full season curriculum. This year, we are asking for a full September–May commitment. If you don’t feel you can commit to this, we can add you to the class for one semester only if there is space available.

If you are planning on joining the WEST Ensemble Players class, please email me directly so I can secure your place in the class.

We jumped on the opportunity, and it looks like everyone else from last year did also.  There is a slightly different feel for a group that works together often—the difference between a pick-up game and a team.  I’m expecting great things of the WEST Ensemble Players this year!

This is my son’s senior year of high school, so his last year with WEST.  Because he has finished all high school graduation requirements except a year of English, half a year of econ, and half a year of civics, he is taking this year to concentrate on his fun subjects:

  • 3 theater classes: WEST Ensemble Players (which filled up before registration opened to the public), Dinosaur Prom Improv (a closed troupe, with the same players as last year) and Page to Stage (a slightly new endeavor for WEST in adapting literature to the stage—with students doing the scriptwriting and directing, as well as the acting). WEST has opened up a couple more intermediate improv classes, probably in the hopes of replacing graduating members of Dinosaur Prom next year and possibly of forming a competing troupe, but since he is already in Dinosaur Prom, he doesn’t need another weekly improv outlet.
    Update—2013 Sept 31: Page to Stage filled up on the first day without any pre-registration, so the teen classes at WEST are indeed in high demand.
  • Two computer engineering projects: extending the Arduino Data Logger he wrote last year (many new features) and the Bluetooth light gloves project.
  • Group Theory as an online class from Art of Problem Solving

And some not so fun ones:

  • AP Chemistry through ChemAdvantage (I won’t be teaching him myself).  This one will not be painful, but is not a big interest.
  • Econ at home (Fall semester)  He may be able to work some of the financial planning for the light-gloves project into this course, as he will be doing a fairly detailed business plan and cost estimation for manufacturing the gloves.  Again, not too painful, but he probably wouldn’t bother if it weren’t a high school graduation requirement in California.
  • Civics at home (Spring semester) Possibly painful, certainly boring, but a high school graduation requirement.
  • English: writing in the fall (a combination of the Page to Stage class, college application essays, and tech writing), dramatic literature in the Spring (with the trip to Oregon Shakespeare Festival).  The writing parts will probably be painful, but we’ll try not to have any make-work writing, but only writing that clearly needs to be done and has a genuine audience.

He’s also looking at some possible community service: being a TA for the Python class gain this year, possibly starting an Arduino/microcontroller club (his consultant teacher wants to see more socialization among the homeschooled computer geeks), and doing a workshop in a few weeks with me to encourage home-schooled middle schoolers and high schoolers to enter the county science fair.  It isn’t obvious whether he’ll enter science fair this year himself—he’d like to have a 7th year at state, just to have done it every year possible, but he doesn’t have any big projects right now other than the data logger (which he took to state last year) and the light gloves (which are an ambitious engineering project, but not the sort of “save-the-world” project that the state judges like—and they generally prefer science to engineering).

We met with our consultant teacher yesterday, and she approved this plan.

2013 July 2

Pressure sensor with air pump

I’ve been thinking of expanding the pressure sensor lab for the Applied Circuits Course to do something more than just measure breath pressure.  Perhaps something that conveys another physics or engineering concept.

One thing I thought of doing was measuring the back pressure and air flow on an aquarium air pump bubbling air into an aquarium. Looking at the tradeoff of flow-rate and back pressure would be a good characterization of an air pump (something I wish was clearly shown in advertisements for aquarium air pumps and air stones).  Measuring flow rate is a bit of a pain—about the best I could think of was to bubble air into an inverted soda bottle (or other known volume) and time it.

This would be a good physics experiment and might even make a decent middle-school product-science science fair project (using a cheap mechanical low-pressure gauge, rather than an electronic pressure sensor), but setting up tanks of water in an electronics lab is a logistic nightmare, and I don’t think I want to go there.

I can generate back pressure with just a simple clamp on the hose, though, and without a flow rate measurement we could do everything completely dry.

Setup for measuring the back pressure for an aquarium air pump (needs USB connection for data logger and power).

Setup for measuring the back pressure for an aquarium air pump (needs USB connection for data logger and power).

Using the Arduino data loggger my son wrote, I recorded the air pressure while adjusting the clamp (to get the y-axis scale correct, I had to use the estimated gain of the amplifier based on resistor sizes used in the amplifier).

The peak pressure, with the clamp sealing the hose shut, seems to be about 14.5 kPa (2.1psi).

The peak pressure, with the clamp sealing the hose shut, seems to be about 14.5 kPa (2.1psi).

I was interested in the fluctuation in the pressure, so I set the clamp to get about half the maximum back pressure, then recorded with the Arduino data logger set to its highest sampling frequency (1ms/sample).

The fluctuation in back pressure seems to have both a 60Hz and a 420Hz component.

The fluctuation in back pressure seems to have both a 60Hz and a 420Hz component with back pressure at about half maximum.

Because the Arduino data logger has trouble dealing with audio frequency signals, I decided to take another look at the signals using the Bitscope pocket analyzer.

The waveform for the pressure fluctuations from the AQT3001 air pump, with the backpressure about 7kPa (half the maximum).

The waveform for the pressure fluctuations from the AQT3001 air pump, with the back pressure about 7.5kPa (half the maximum).

One advantage of using the Bitscope is that it has FFT analysis:

Spectrum for the back pressure fluctuation.  One can see many of the multiples of 60Hz, with the particularly strong peak at 420Hz.

Spectrum for the back pressure fluctuation. One can see many of the multiples of 60Hz, with the particularly strong peak at 420Hz.

I was also interested in testing a Whisper40 air pump (a more powerful, but quieter, pump). When I clamped the hose shut for that air pump, the hi-gain output of the amplifier for the pressure sensor saturated, so I had to use the low gain output to determine the maximum pressure (24.8kPA, or about 3.6psi). The cheap Grafco clamp that I used is a bit hard to get complete shutoff with (I needed to adjust the position of the tubing and use pliers to turn the knob).  It is easy to get complete shutoff if the tube is folded over, but then modulation of less than complete shutoff is difficult.

The fluctuation in pressure shows a different waveform from the AQT3001:

The Whisper40 air pump, with the clamp set to get about half the maximum back pressure, produces a 60Hz sawtooth pressure waveform, without the strong 420Hz component seen from the AQT3001.

The Whisper40 air pump, with the clamp set to get a bit less than half the maximum back pressure, produces a 60Hz sawtooth pressure waveform, without the strong 420Hz component seen from the AQT3001. The peak-to-peak fluctuation in pressure seems to be largest around this back pressure. The 3kPa fluctuation is larger than for the AQT3001, but the pump seems quieter.

The main noise from the pump is not from the fluctuation in the pressure in the air hose, but radiation from the case of the pump. That noise seems to be least when the back pressure is about 1.1kPa (not at zero, surprisingly). The fluctuation is then all positive pressure, ranging from 0 to 2.2kPa and is nearly sinusoidal, with some 2nd and 3rd harmonic.

As the back pressure increases for the Whisper40, the 2nd, 3rd, and 4th harmonics get larger, but the 60Hz fundamental gets smaller. The 4th harmonic is maximized (with the 1st through 4th harmonics almost equal) at about 22.8kPa, above which all harmonics get smaller, until the air hose is completely pinched off and there is no pressure variation.

When driving the large airstone in our aquarium, the Whisper40 has a back pressure of about 7.50kPa (1.1psi) with a peak-to-peak fluctuation of about 2.6kPa.

I’m not sure whether this air-pump back-pressure experiment is worth adding to the pressure sensor lab.  If I decide to do it, we would need to get a dozen cheap air pumps.  The Tetra 77853 Whisper 40 air pump is $11.83 each from Amazon, but the smaller one for 10-gallon aquariums is only $6.88.  With 12 Ts and 12 clamps, this would cost about $108, which is not a significant cost for the lab.

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