Friday, September 19, 2014

Marble momentum

This term I was battling a nice tropical head and chest cold. Devoid of energy and lacking much in the way of voice, I put directions on the board. I opted not to lead off with a demonstration - making this term different from prior terms. I did not run my usual "how does the penultimate marble know what to do" patter. I did have to adjust from groups of two to four to allow each group to have two stopwatches, a recorder, and a marble pitcher.

Judy Andon and Mailynda Maycry

Jasmine Santos and Mark Jones time marble runs

Jessica Reyes and Lodonna Osawa discuss measurement approaches, Marti works with Laslyn in the background



Set-up, donuts are optional

Notes from the board plus data

Group presentations focused on these two questions

Mark Jones presenting

Vanity Paul and Alex Etse jointly presenting

Mailynda presents

Jessica Reyes explains her group's findings 

Marti Henry presenting

Pernes Bernis and Malcom Tom present their findings

Pernes continuing the explanation

Lerina Nena speaks on behalf of her group

Christopherson tells the other teams what they found

Brenda Paul presenting

The directions were minimalist at best, and this term that seemed to work just fine.

Wednesday, September 17, 2014

RipStik energy conservation and banana leaf marble ramp notes

On Monday I tried to show that energy is conserved by trading GPE at the top of a slope for KE at the bottom. I used the covered walkway between the A and F buildings. My final velocity was difficult to obtain, I could only time the final 303 post-to-post centimeters to estimate my velocity. The real complication proved to be the height h. Without a level I could not accurately level the line I used to determine the height h. Memo to self: obtain a level before trying this again.

Although I started in centimeters, the numbers generated by working in cgs (70000 g, 14140000 g cm/s of momentum) appeared to be clouding the physics for the students and worked against rounding to mentally comprehensible numbers. So I switched to MKS. 

A mass of 70 kg (myself plus my RipStik measured using a metric spring scale), a g of 9.70 m/s², and a height of 0.09 meters yielded 62 Joules of GPE. A final speed of 3.03 meters/1.4 seconds (2.02 m/s) yielded a kinetic energy of 141 Joules. Thus my line was low. I had tried to level the line against the roof line of the north faculty building, I obviously failed. I was not wearing pants conducive to laying on the ground. More notes to self - wear grunge next time, bring that level. The "right" height is somewhere near 20 cm.

Wednesday I modified the marble ramp. By bringing extra meter sticks I was able to set up a T at the end of the 100 cm run. The leaf was hung low, only a 50 cm max height possible. I did heights at 5, 10, 15, 20 ,25 and 50, timing from 0 cm to when the marble slapped the end stick. This eliminated the sharp speed losses seen when I would shift from 100 cm to 200 cm lengths. I did all at 100 cm. The fastest marble, the 50 cm drop, timed in at 0.31 seconds. I was able to consistently and repeatedly repeat times in the low 0.30s for this marble.

height actual linear energy
(cm) velocit predict prediction
 (cm/s) (cm/s) (cm/s)
0 0 0 0
5 71 71 98
10 109 143 139
15 139 214 170
20 169  197
25 189  220
50 323  311

The use of the end stick has generated numbers closest to theoretic yet generated - somewhat coincidental/accidental given that the loss of energy due to spin up was not factored in. The corrected coefficient is down around 34 times the square root of the height.

Thursday, September 4, 2014

Measuring the acceleration of gravity

Measuring the acceleration of gravity by timing the fall time for a super ball from 0, 100, 200, 300, 400, and 500 centimeters. This laboratory features a transformation of the x-axis. Squaring the time and then dividing by two and plotting against the fall distance yields a straight line with a slope equal to the acceleration of gravity. This brings a linear relationship into the heart of an acceleration measurement. This also reduces the complexity of the math down to where students with weak algebraic foundations can begin to understand the system mathematically. The lab in the text details the procedure.

Marti Henry drops and times, Jessica Reyes holds meter sticks.

V-ann retrieves the super ball

Paulino Perman times and drops, Alex holds meter sticks, Mailynda Maycry records the data.

Dropping from 400 centimeters is obtained outside.

Lodonna Osawa and Jessica Reyes

Marla Silbanuz records data gathered down the table

Edward Reyes drops the super ball from 400 cm

Monday, September 1, 2014

RipStick deceleration acceleration

The RipStik deceleration and acceleration built off of a lecture introduction first to negative slope, negative velocity, and a return to zero distance. I then suggested a gradually slowing, stopping and returning with acceleration would yield some form of curve. This built off of the last five questions on the velocity quiz last week. I finished the lecture demonstration with the arc of a ball on the board, parabolas, and the suggestion of a quadratic equation. Then I went outside to make one.

I used the same zero post as the week before and a 305 cm on center measurement. After a couple practice runs I did a run that I thought went to 1220 cm out and back. I could not make the times work, became confused, and decided to redo the RipStik run. This time I realized I was turning just past the 915 cm post, so my original data was not faulty. The graphs below retain both sets of data.

A roughly parabolic shape emerged from both runs, both runs have very similar time versus distance profiles.

My velocity changes in a negative linear fashion, decreasing at a roughly constant rate until the very end of the run.

My deceleration remains in the -30 to -60 centimeter per second range until the end of the run.

Just past the turn around at an estimated 1050 centimeters.

Data table:

time (s) distance run one (cm) distance run two (cm)
0 0
1.09 305
2.54 610
4.69 915
6.66 1050
9.06 915
10.76 610
12.21 305
13.59 0

Sunday, August 31, 2014

Monilophyte and Lycophyte hike

This term two students asked to meet the class at the trail head down by agriculture, and other were waiting down by the gym for the class. So at 3:20 PM I picked up moss with sporophytic spore capsules from the Premna obtusifolia on the eastern edge of the campus. I also grabbed a fertile Microsorum scolopendria frond and a Davallia solida frond. I knew a fertile kidou frond and ulungen kiehl would be harder to find on the trail. At 3:30 I was back at the classroom and headed west with the dozen students I found there. I found the cyanobacteria Nostoc at the east edge of the main parking lot along the drainage gutter. I put everything into a plastic bag. The one note for future terms is to bring more bags, smaller bags, clear bags. Everything was a jumbled mess by the time I reached the nan mahl.

Heading west I took the most direct route, the students trailed in a broad arc. Up at the Lycopodiella cernua patch, which is increasingly well developed, I pulled out the Nostoc and began the lecture. This was the first time I had tried this approach. Nostoc was previously covered on day one, but the use of the second half of the period to introduce Schoology on day one has knocked cyanobacteria out of the day one lecture. This term the ethnogarden cleaning featured no cleaning whatsoever and turned into an introduction to the plants of the campus.

Melody Tulenkun on point coming down from the Lycopodiella cernua, Dicranopteris linearis patch. Jake Manuel behind her.

The long stop at the Lycopodiella cernua patch proved beneficial. Three different groups of late arriving students could hear my less than mellifluous voice from up at the agriculture parking lot and were thus able to find their way down to where the class was along the trail. When the stragglers complained about having been left behind, I noted that I left the A101 classroom at 3:30, at the class starting time.

The trail does not look like such to someone not from here, but this trail is actually commuted on daily by many people.

The coverage of Nostoc, bryophyta, Lycopodiella cerna, and Dicranopteris linearis plus the associated terminology of spores, sori, cones, haploid, diploid, meant that the class did not leave the Lycopodiella patch until 4:14.

Virginia Sartilug makes her way down slope

Melody studies the latest edition of the primitive plants list, a LibreOffice/OpenOffice document with the Latin and local names of the plants. A text copy of this list is included at the end of this blog.

Virginia Sartilug and Andrea Ewarmai amidst C. maemonensis and Nephrolepis ferns
At the top of the slope the monilophyte and lycophyte collection includes Nephrolepis, Cyclosorus maemonensis, Microsorum scolopendria, Huperzia phlegmaria, Haploteris elongata, and Asplenium nidus. A young Sphaeropteris nigricans has grown over the past decade such that I can now cover that fern at the steep slope top. This is particularly useful as this leaves only a few ferns to be covered in the valley, allowing me to excuse students with medical or physical conditions from descending into the valley of the ferns.

A couple meters down the steep slope on the right is a new Asplenium laserpitiifolium plant. A few meters further down slope is Asplenium polyodon. I did not see Davallia pectinata on this trip, the time was pushing towards 4:30 and I felt I did not have time to conduct a solid search for the small epiphytic fern.

Melody headed back up slope
Because I covered the A. laserpitiifolium up on the slope, I moved rapidly across the valley floor and headed directly for the Antrophyum callifolium Blume (indigenous) (Syn reticulatum G.Forst). known in Pohnpeian as tehlikinwel. The class continued on to the Angiopteris evecta known in Pohnpeian as peiwed (poaiwed) and in Yapese as m'ong.

Ruthy Phillip heads back up slope
Although the trail is used daily by local children and the elderly, the climb is steep and slippery. The slope will wind a person who is not in good shape and is unaccustomed to the high humidity of a rain forest. There is zero ability to cool via sweating, and the slope is steeper than it appears in photographs. The college does have students with medical conditions, some undiagnosed and not known to the student themselves. Hence this portion of the hike is not without risk factors. That said, the difficulty of the task helps begin to bond the class as a unit.

Heading out towards the Lycopodiella patch.

1. Latin: Nostoc spp.
English: cyanobacteria
Kosraen: fokon faht
Pingelapese: limw (lihmw is Pohnpeian for green algaes in general)
Mwoakillese: pwijen joau (soau is honorific for sun in high Pohnpeian)
Pohnpeian: pwisehn ketipin
Kitti: pwisehn koatipin
Kapinga: gili ' moana
Mortlockese: paniol
Northern Noumenean: num
Faichuukese: num
Woleaian: luumule
Yapese: la'law
2. Moss: Musci
Use: fragrance for coconut oil (K)
English: moss
Kosraen: lum
Pingelapese: limw
Pohnpeian: lihmw
Kitti: lihmw
Mortlockese: lum?
N. Noumenean: num
S. Noumenean: nuum
Faichuukese: nūūm
Satawalese: nwumw
Pollapese: luumw
Woleaian: luumwe
Ulithian: lluum
Yapese: ganir
3. Psilotum: Psilotum nudum
English: whisk fern
Marshallese: martok
4. Lycopodium:
Lycopodiella cernua
Use: Cockroach repellent (P) decoration (C, K, P), arthritus bath (Hawaii, Sumner, 2008)
English: christmas tree club moss
Kosraen: mah in twefuroh
Pingelapese: suhke krismas
Pohnpeian: kidienmal, kidim en mal
Unk C: wúnen kattu
N. Noumenean: unen katu
Faichuukese: ūn-en katu , unen kattu
Puluwatese: kaatu
Woleai: gashishil gaatu
Ulithian: pechalgaatuw (cat's tail)
Yapese: gama'
Fijian: lawanini
5. Fern: Dicranopteris linearis
Use: None
English: false staghorn fern
Pohnpeian: mwedil en mal
Kitti: mwoadil en mal
N. Noumenean: anecha
S. Noumenean: an-nucha
Faichuukese: anecha
Woleaian: gemarag
Ulithian: hamarag
Yapese: gana'
Fijian: qato
6. Fern: Nephrolepis spp.
Use: keep water in bucket (K); cockroach repellent; 4 fiddleheads anti-diuretic or to calm nerves (P); decoration (C)
English: sword fern
Marshallese: anmokadede
Kosraen: ka
(Kenye Nipinyuck Waguk Mongkeya, 2007)
Pingelapese: pweh
Mwoakillese: pwoa
Pohnpeian: rehdil
Kitti: roahdil
Nukuoran: luu'he
Kapinga: lo'godaha
N. Noumenean: amare
Faichuukese: ammaru
Pollapese : amaare
Puluwatese: amare
Satawalese: aemaerei
Woleaian: gemarag
Yapese: alaw' (cockroach)
Fijian: diqi waruwaru
7. Fern: Cyclosorus maemonensis
Use: Washing dishes, tinea versicolor antifungal, local toilet tissue (P), grass skirt (Y)
Kosraen: fa
Mwoakillese: pwoa
Pohnpeian: mahrek
Kitti: marek
Nukuoran: manu'a tababa
Faichuukese: moromoren uuch
Puluwatese: hifin keerh
Woleian: mwatig
Yapese: walem (skirt)
8. Fern: Microsorum scolopendria
Use: Anti-diarheal (K, P) , mwarmwar for dancers (P, W), child's skirt (W), bone medicine
English: fragrant fern or maile-scented fern
Marshallese: kino
Kitti: kidou
Kosraen: sra kwemkwem
Pingelapese: pweh, kideu
Mwoakillese: kamkam
Pohnpeian: kideu
Kitti: kideu
Kapinga: gideu
Mortlockese: amāāra, amááre
Noumenean: chiichi
Unk C: Wénnúmey, sichon
Puluwatese: rhiirhi, riiri
Pollapese: rhirhi
Satawalese: rhirhi
Ulithian: chichi
Woleaian: shishi
Yapese: gob u ley (swamp)
Yapese: gob (drier place)
Fijian: kadakada
9. Fern: Asplenium polyodon or possibly A. pellucidum (tentative)
Pohnpeian: mahrekenleng, rehdil rasaras, rehdil en naniak
Kitti: mahrekenloang
10. Fern: Davallia solida
Pohnpeian: Ulung en kieil
11. Fern: Davallia pectinata (Humata banksii (Alston)
Pohnpeian: limwediliniak, kelmahu
Puluwatese: imwediliniak
12. Psilotum: Psilotum complanatum
Woleai: tiig
Yap: tilbug, dilbug
13. Lycopodium: Huperzia phlegmaria
Use: Mwarmwar for dance (P)
English: lycopodium
Pohnpeian: limpahr, limpar
Kitti: limpar
Yapese: awol (centipede)
Fijian: sevaseva
14. Fern: Haploteris elongata (Sw.). Syn. Vittaria elongata.
Use: Used with local oil to strengthen hair (K), or with water (P, Y)
Pohnpeian: alis en kewelik, alis en Nahnsou sed (honorific for heron), mwosou
Kitti: alis en koawoalik, alis en nahnsoau sed
Mortlockese: ishish
Pollapese: olen maluk
Puluwatese: olan maluk
Yapese: rob (beard)
15. Fern: Asplenium nidus
Use: On yams (P) , leaf tips for soup (Y)
English: bird's nest fern
Marshallese: kartōp
Kosraen: muhlihklihk
Pingelapese: sehlik
Mwoakillese: kardoap
Pohnpeian: tehnlihk
Kitti: toahnlik
Nukuoran: lau gadaha
Kapinga: lo'goho
Mortlockese: chōōlik
Unk C: nnuk
N. Nomenean: nuuk
Faichuukese: nukk , nnūk
Puluwatese: rhM lkk
Pollapese: rhēlūk
Woleaian: iuliuniug
Ulithian: maching (easy to break)
Yapese: chath
Fijian: beluve
16. Fern: Sphaeropteris nigricans (Cyathea nigricans)
Use: Posts for nahs, leaves as mats (P)
English: tree fern
Kosraen: po, tukun inut
Pingelapese: kesar
Mwoakillese: kasar
Pohnpeian: katar
Kitti: katar
Nukuoran: maele
Yapese: yibung
Fijian: balaba
17.  Fern: Asplenium laserpitiifolium Lam.
Japanese: Okinawa-sida
18.  Fern: Cephalomanes atrovirens
Pohnpeian: didimwerek
19. Fern: Antrophyum callifolium Blume (indigenous) (Syn reticulatum G.Forst).
Use: Undetermined to date
20.  Angiopteris evecta
Pohnpeian: Peiwed (Poaiwed), paiued
Yapese: m'ong

Velocity of a rolling ball

Since spring term 2014 laboratory two has been moved to occur between the LRC and the south faculty building. This laboratory builds on the Monday linear RipStik velocity homework which was then covered on Wednesday. The Wednesday lecture included the segment speed post-to-post for the RipStik to demonstrate that the speed is changing slightly and the slope, if inspected carefully, also reflects those subtle speed changes. Wednesday also saw coverage of stationary and infinite velocity objects on time versus distance graphs. This provides a solid introduction to laboratory two. The shift away from the gym was made to permit moving into the computer laboratory at the end of this laboratory to assist the students with making a graph with five trend lines and to continue to assist the students with using Schoology. This session is particularly necessary for getting laboratory one correctly submitted. Laboratory three will be the last laboratory in the term start set to use the computer laboratory.

Alex Etse bowls, Mark Jones times. V-Ann Nakamura, Jessica Reyes, and Marti Henry track position of the ball at one, two and three seconds.
This laboratory might be done elsewhere with tracking the time the ball passes a pre-measured location. That is the way the Monday RipStik run is done. This procedure, however, makes the distance the independent variable and the time the dependent variable. There is a convenience sample of 56 respondents to a poll posted in Schoology Science where 53 respondents note the use of the terminology independent variable/dependent variable. Three respondents chose the alternate terminology manipulated variable/responding variable. The latter terminology is clearer but less favored. One commentator noted his use of explanatory/response variable.

Mailynda Maycry watches for the four second location, Judy Andon is monitoring the fifth second.

The college algebra text in use in the college uses the more opaque independent and dependent variable language, hence I use that language. I note that we chose the times. We were free to choose any time we wanted to choose. Our choice was an independent and free choice. The distance we measured then depended on the time we chose. We had no choice. The procedure has Mark calling out the times. V-Ann watched for where the ball WAS at one second. That word choice of  "was" seems to be important to getting a good fix on the ball location.

Keeping the ball straight down the middle is challenging.

Density of soap

Monday, the first day of class for the fall term, I briefly covered the syllabus and introduced the course. By 12:30 I passed out the pre-assessment which was slightly revised and expanded from previous editions.The pre-assessment problems focus on density. On Wednesday when I pass back the marked pre-assessment and go over the answers, the students are also being introduced to the mathematics of density and one of the twin core themes in the course. The course focuses on mathematical models and writing.

Laboratory one remains essentially the same as it has been for the past seven years. The laboratory acts to introduce metric measurements in centimeters. Centimeters will then be used in laboratories two, three, and four. RipStik demonstrations are also now all done in centimeters and seconds
Jessica Reyes and V-Ann Nakamura
To keep the laboratory within a 90 minute time frame, I switched a few terms ago to electronic scales to determine the mass. The quadruple beam Cent-o-gram balances are more concrete and visual, but do not necessarily aid understanding in what mass really is. A deep understanding of mass is difficult for anyone to arrive at and I would venture to guess that for all of my students mass and weight are completely entangled concepts.

Marti Henry measures while Laslyn Siden inspects her soap. Lodonna Osawa looks on.

The second half of the three hour laboratory is spent in the A204 computer laboratory. The laboratory format is introduced and the use of Schoology LMS is covered.

Gordon Loyola carves his soap.

Marla Silbanuz records the measurements being made by Cherish Laiuetsou

Edward Reyes carefully but comfortably works on his soap chunks.

Data gathered from Dial Basic soap. Ivory is always used along with other sinking soaps. Each group works with only one kind of soap, but up in the computer laboratory I ensure that the class is aware of the slope based prediction that the Ivory soap will float. And the Ivory knows what to do - the Ivory floats when placed in a beaker of water that I bring up to the computer laboratory, thus echoing the quote I read at the start of the laboratory:

For a physicist mathematics is not just a tool by means of which phenomena can be calculated, it is the main source of concepts and principles by means of which new theories can be created... ...equations are quite miraculous in a certain way. I mean, the fact that nature talks mathematics, I find it miraculous. I mean, I spent my early days calculating very, very precisely how electrons ought to behave. Well, then somebody went into the laboratory and the electron knew the answer. The electron somehow knew it had to resonate at that frequency which I calculated. So that, to me, is something at the basic level we don't understand. Why is nature mathematical? But there's no doubt it's true. And, of course, that was the basis of Einstein's faith. I mean, Einstein talked that mathematical language and found out that nature obeyed his equations, too. – Physicist Freeman Dyson