Barvni kolaž brez barvil

Kosmač, Mihaela (author), Čepič, Mojca (mentor)

Ko med polarizatorja vstavimo predmet iz brezbarvne anizotropne snovi (npr. selotejp) in ga sučemo, opazimo barve. Te lastnosti pojava umetniki izkoriščajo v likovni umetnosti. Metoda je znana pod imenom »Polage art« oziroma barvni kolaž brez barvil. Z ustvarjanjem barvnih kolažev, je v umetnosti zaslovela Austin W. Comarow, ki svoje umetnine razstavlja v bostonskem naravoslovnem muzeju (Wood Comarow, 2020). Pri ustvarjanju barvnega kolaža na brezbarvno optično izotropno podlago (npr. trda cvetličarska folija) lepimo polarizator, brezbarvno anizotropno folijo (npr. selotejp), polarizator in zopet brezbarvno anizotropno folijo. Pri lepljenju je pomembna medsebojna orientacija polarizatorjev in prozornih anizotropnih folij, da vidimo eno sliko brez tretjega polarizatorja (slika 1a), drugo pa z njim (slika 1c). V magistrskem delu sem oblikovala zbirko aktivnosti, ki učitelju omogoča, da učencem predstavi nabor eksperimentov, kjer učenci spoznavajo pod katerimi pogoji nastanejo barve pri prehodu svetlobe skozi materiale, ki ne vsebujejo barvil. Z barvnimi kolaži lahko pri učencih spodbudimo željo po razumevanju, kaj se zgodi s svetlobo, ki se širi skozi dvolomno snov. Uporabo dvolomnih snovi srečamo vsakodnevno: v prikazovalnikih LCD, 3D očalih in v merilnih napravah. Učencem bi s poučevanjem te vsebine približali delovanje nečesa, s čimer se vsakodnevno srečujejo. Hkrati pa bi jim približali aktualnost in sodobnost fizike. Za učiteljevo razumevanje fizikalnega ozadja eksperimenta sem v teoretičnem delu preučila: polarizacijo svetlobe, anizotropne snovi in njihove lastnosti, dvolomnost, širjenje svetlobe v dvolomni snovi ter nastanek barv pri prehodu svetlobe skozi optično anizotropno snov. Teoretična razlaga fizikalnih pojavov je prepuščena kasnejši obravnavi v srednji šoli, saj je glede na predznanje učencev v osnovni šoli razlaga prezahtevna. V praktičnem delu sem sestavila zaporedje aktivnosti, ki vodijo do ideje, da so potrebni trije polarizatorji in prozorne anizotropne folije, da lahko oblikujemo dve sliki v eni sami. Pomembna je medsebojna orientacija polarizatorjev in folij, kar omogoči, da vidimo eno sliko brez tretjega polarizatorja, drugo pa z njim. Učenci bodo z vodeno aktivnostjo načrtno raziskali različne odvisnosti, pri čemer bo njihova naloga načrtovanje, postavljanje in preverjanje napovedi ter oblikovanje končnih sklepov. Na podlagi teh aktivnosti bodo spoznali pod katerimi pogoji nastanejo barve pri prehodu skozi materiale, ki ne vsebujejo barvil. Učenci se bodo na izkustvenem nivoju seznanili s polarizacijo, anizotropijo in barvami. Za konec pa bodo sami izdelali tudi barvni kolaž. Učna enota je namenjena učencem osmega ali devetega razreda. Za izvedbo aktivnosti učitelj potrebuje približno pet šolskih ur. Ker se v razredu učitelj že tako pogosto sreča s časovno stisko, predlagam izvedbo aktivnosti v okviru projektnega dela, naravoslovnega dneva ali kot delavnico v okviru šole v naravi. Z nalogo sem želela ugotoviti, ali je aktivnost primerna in obvladljiva na osnovnošolski ravni ter katera znanja in veščine učenci usvojijo. Zanimala me je tudi časovna, materialna in organizacijska zahtevnost predlagane dejavnosti. Zaradi razmer, v letošnjem šolskem letu zaradi COVID19 izvedba aktivnosti in analiza nista bili izvedljivi.

• Language: Slovenian
• Keywords: polarizacija svetlobe
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: PEF - Faculty of Education
• Year: 2020
• PID: 20.500.12556/RUL-125014
• COBISS.SI-ID: 53212931
• Publication date in RUL: 02.03.2021

Secondary language

• Language: English
• Title: Polage art without dies

Abstract

Colours can be observed if anisotropic material (eg. adhesive tape) is inserted between two polarizers and rotated. Artist are using this optical phenomenon in their art. This type of art is known as “Polage art”. Austin W. Comarow became famous for her polage art and she also exhibits her work in Boston Museum of Natural History. For creating a polage one needs a colourless anisotropic foil (eg. cellophane), on top of the basis one sticks a polarizer, a colourless anisotropic foil (eg. adhesive tape), another polarizer and again a colourless anisotropic foil. The orientation between the polarizer and the colourless anisotropic foil is the reason one can see one image without the third polarizer and one through it. This work includes a collection of tasks and experiments which can help teachers to discuss the formation of colours in colourless materials with students. Students can be motivated by polage art in understanding the phenomenon of light transition through a birefringent material. Birefringent materials can be found in LCD screens, 3D glasses and in measuring devices. Content of this work can be used in showing the physics in everyday use and to demonstrate how physics is important in our lives. The theoretical part includes a theory on polarization of light, anisotropic materials and their properties, birefringence, propagation of light through birefringent materials and a creation of colours when light passes through an anisotropic material. Theory serves as a help to a teacher for understanding the background of experiments. Some elements of the theory could be presented to students in high school, as the knowledge in primary school is not sufficient to understand the physics in background. Practical part presented in this work is a series of activities for students in the lower secondary school. Those activities lead to understanding of creating two pictures in one by combining three polarizers and transparent anisotropic materials. Students experientially learn about the polarization, anisotropic and colours. Students learn that colours are observed when light propagates through colourless material. Students learn about the importance of orientation of anisotropic material between polarizers as orientation is the key why one picture can be seen without a polarizer and one with an added polarizer. Through a guided activity, students systematically explore various dependencies leading to the final task, that is to plan, set and check predictions, and form final conclusions in preparation for the polage of their creation. At the end of activities, they create their own polage art. This learning activity is suitable for students in 8th or 9th grade of lower secondary school. There are about five school hours required for a teacher to demonstrate activities described in my master's thesis. I suggest implementing these activities in a type of project work, science day or as an activity in a field work school. One of the goals of the master's thesis was also to determine whether the activity is appropriate and manageable at the lower secondary school level and what knowledge and skills students acquire. I was also wondering how difficult it is to organise activities, how much time will I need and what resources are required. Implementation and analysis of activities were not possible in this school year due to the COVID 19 pandemic and a quarantine.

• Keywords: light polarization