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Earth – a somewhat bigger laboratory for school Physics
Grzegorz Karwasz Andrzej Karbowski Krzysztof Służewski Zakład Dydaktyki Fizyki, Uniwersytet Mikołaja Kopernika w Toruniu
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Rationale (I): Polish National Curriculum Base (2007)
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Rationale (II): XXI Century Science
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XXI Century Science
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XIV: Structure and evolution of Earth
Litosphere Hydroshere Atmosphere (Crysphere) Biosphere XV: Structure and evolution of Solar System
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Didactical/ heurestic goal
Bring together Physics & Geography Illustrate, possibly experimentally, phenomena Choose the minimum knowledge requirements Make the whole package attractive Didactical theory context: neo-realism (show as much as you can, and even more), hyper- constructivism (make student construct his/ her knowledge from apparently nothing, i.e. pre-existing knowledge in his/her mind) G. Karwasz, Problemy Wczesnego Nauczania, 2013 G. Karwasz, GIREP Conference 2012
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Case examples: radioactivity → the age of Earth
two-body mechanics → Earth and Moon gravity and rotation → shape of Earth convection and radioactivity → shield tectonics electromagnetic induction → magnetic field Coriolis force → general dynamics of atmosphere Coriolis force → dynamics of oceanic currents latent heat & convection → tropical storms
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Three heurestic functions of an interactive/multimedia object
Child: that’s so funny! Pupil: that’s so easy! Scientist: that’s so complex! G. Karwasz, J. Kruk, Idee i realizacje dydaktyki interaktywnej, Wyd. Nauk. UMK, 2012
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Radioactive series In other words: a starting point 238U
some „bottle necks” an ending point 206Pb rad lat, gaz radon - 3,8 dnia, polon - 3 minuty, ołów - 27 minut (ten rozpada się przez proces β); bizmut - 20 minut; w kolejnym rozpadzie β powstaje ponownie polon, ale inny izotop, żyjący zaledwie 0,16 milisekundy, itd.
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What is the age of Earth/Solar system?
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What is the age of Earth? Science 321, 1828 (2008); Jonathan O'Neil, et al. Neodymium-142 Evidence for Hadean Mafic Crust Science 309, 576 (2005); M. Boyet, et al. Silicate Earth 142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth
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What is the age of Universe?
Planck mission (March 2013): bilion yrs
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Moon – a companion from (almost) ever
4.567 bln yrs + ~100 mln yrs ago
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„Satelite” = body guard
G. Karwasz, M. Więcek, Toruński po-ręcznik. Fizyka współczesna, ZDF UMK 2012
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„Satelite” = orbit stabilizer
Physics and Toys → destabilisation of Earth’s axis in 100 mln yrs
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„Jakiego kształtu jest kula ziemska
„Jakiego kształtu jest kula ziemska?” What is the shape of Earth’s ball? Answer: „Geoide” = Earth-like shape Foto: ESA = tautology
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Copernicus: Why water does not flow down from Earth’s ball?
Także i wody morskie układają się do postaci kulistej [...] jako ląd i woda wspierają się na jednym środku ciężkości Ziemi, który jest zarazem środkiem jej objętości. Newton: Because of gravity remained: „what is the shape of Earth?”
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Newton: Elipsoid because of the centrifugal force
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Centrifugal force from textbooks
waves of kilometric heights would flush down the globe!
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Elipsoid is perpendicular to the effective gravity force
„flatness” 1/297
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Parabole is perpendicular to the effective gravity force
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Springs in mountains flow perpendicularly to iso-height lines
In physics we call these lines - equi-potential lines: the gravity force is perpendicular to potential lines
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Ellipsoid vs. geoid i.e. geometry vs. physics
Geoid – constant (gravitational + centrifugal) potential surface
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GOCE: equipotential lines
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Earth’s shape: equipotential surface
± 100 m
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Earth’s shape: equipotential surface
Geoid is lower than elipsoid in the Himalaya mountains! Potential formula: V=GM/r2 Lower mass → lower r Himalaya are ligth (calcite) rocks
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What is the shape of Earth?
The one, shown by the lever (libella) and this is perpendicular to the vertical Poziomica, pion
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Earth’s shape: horizontal water
because water level is always horizontal, like Copernicus said
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What is the Earth’s internal structure?
S-wave in iron: 3,24 km/s P-wave in iron: 5,95 km/s Sprężyny, stukot
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What is the Earth’s structure?
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What is the Earth’s structure?
crust ↔ litosphere mantello ↔ astenosphere G. Karwasz, J. Chojnacka, Geografia w Szkole, 2012
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How old is Europe? M. Grad, T. Tirra, and ESC Working Group,
The Moho depth map of the European Plate, Geophys. J. Int. 176 (2009), str. 279.
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What is the Earth’s crust?
Lampa Lava
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Why this vertical movement?
Heat flux: 238U: 8 TW (1015 W) 232Th: 8 TW 40K: 4 TW cooling: 20 TW (electricity production: 10 TW) Physics World, March 2013
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Melting and solidifying
Lampa Lava
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Quarz, olivine etc. Mg2SiO4
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so, the vertical structure is getting complex
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so, the vertical structure is getting quite complex...
Nature09401-f1.2.jpg
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Geo-fizyka dla nie-fizyków
„Pangea” Geo-fizyka dla nie-fizyków 300 mln yrs ago Justyna Chojnacka Zakład Dydaktyki Fizyki Wydział Fizyki, Astronomii i Informatyki Stosowanej
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and the surface structure?
some 500 mln yrs ago
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Moving continents + 50 mln yrs (?) wosk
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Colliding continents (I)
John Nábelek, et al. Science 325, 1371 (2009); Foto: J. Karwowski, M. Karwasz, M. Visintainer
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Colliding continents (IIa)
Westward: Japan Subduction angle: 45º Dwie kartki papieru
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Colliding continents (IIb)
Eastward: Andes Subduction angle: 15-25º
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Colliding continents (III)
Subduction of oceanic plates Physics World, no 3. (2012) Ryc. K. Konieczna
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IV Continents drifting away
Foto M. Karwasz
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IVa Continents drifting away
Foto M. Karwasz
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Earth’s magnetic field
Dynamo model
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Magnetic nigthingales
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Auto-generated electric super-currents → auto-generated magnetic fields
Illustration of the dynamo mechanism that creates the Earth's magnetic field 389371aa.eps.2.gif
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so, it is getting quite complex
Glatzmaier and Roberts 1995
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Atmosphere: Coriolis force
Ω v -2Ω×v
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Atmosphere: Coriolis force
Ω v -2Ω×v
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Atmosphere: Coriolis force
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Atmosphere: Coriolis force + rotation
High troposphere: Earth’s rotation Troposphere: Coriolis around the two Tropics
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Atmosphere: Tropics and trade winds
Why Tropics are high pressure regions? subtropical and polar jet streams It is dry (descending) air!
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Atmosphere: Columbus plan
Seasonal changes in Earth’s axis angle between September and March (1492/3)
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Coming back to oceanic circulation
Chile (Humboldt)
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Atmosphere: simple mechanisms, complex pattern
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Atmosphere: vertical motion
Heat of condensation 540 cal/g → Heating high troposphere → augmented air convection Warm ocean & Wind-induced evaporation media/objects/3312/ /blb1801.html
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Wind-driven oceanic circulation
Northern hemisphere: clockwise, like Gulf stream, California Southern hemisphere anti-clockwise: Chile (Humboldt), Kalahari) antyzegar
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In-depth oceanic circulation
Gulf Stream will stop if waters around Iceland warm up akwarium
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Time-dependent patterns: Fourier components
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Atmosphere (II): Fourier components
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Interdisciplinary search
You will find the other rocks lie lower, but they are so close together that there is not more than a bowshot between them. [A large fig tree in full leaf grows upon it], and under it lies the sucking whirlpool of Charybdis. Three times in the day does she vomit forth her waters, and three times she sucks them down again; see that you be not there when she is sucking, for if you are, Neptune himself could not save you; you must hug the Scylla side and drive ship by as fast as you can, for you had better lose six men than your whole crew Homer, Ulysses
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Homer: Scilla & Charybdis
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In-between Scilla and Charybdis
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Messina Strait 3 times a day!
Fontanna Herona, Fala w misce w przewężeniu
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A bigger wave: tsunami
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Geophysics cardinal points
Earth’s age: 4,567 mln yrs Moon: 1/4 of Earth’s diameter Shape: almost spherical 1/297 ± 100m Tectonics: colliding every some 300 mln yrs Cryosphere: bistable system, ~40k yrs Atmosphere: Coriolis force + 7 days synoptic Fourier component Oceans: wind-driven (clock or anti-clock) Significant human impact
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Conclusions: Need for interdisciplinary Science teaching
Physics with Geography Physics with Chemistry Geography with Literature ... Biology with Philosphy Thank you very much!
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