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Earth – a somewhat bigger laboratory for school Physics

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1 Earth – a somewhat bigger laboratory for school Physics
Grzegorz Karwasz Andrzej Karbowski Krzysztof Służewski Zakład Dydaktyki Fizyki, Uniwersytet Mikołaja Kopernika w Toruniu

2 Rationale (I): Polish National Curriculum Base (2007)

3 Rationale (II): XXI Century Science

4 XXI Century Science

5 XIV: Structure and evolution of Earth
Litosphere Hydroshere Atmosphere (Crysphere) Biosphere XV: Structure and evolution of Solar System

6 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

7 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

8 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

9 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.

10 What is the age of Earth/Solar system?

11 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

12 What is the age of Universe?
Planck mission (March 2013): bilion yrs

13 Moon – a companion from (almost) ever
4.567 bln yrs + ~100 mln yrs ago

14 „Satelite” = body guard
G. Karwasz, M. Więcek, Toruński po-ręcznik. Fizyka współczesna, ZDF UMK 2012

15 „Satelite” = orbit stabilizer
Physics and Toys → destabilisation of Earth’s axis in 100 mln yrs

16 „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

17 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?”

18 Newton: Elipsoid because of the centrifugal force

19 Centrifugal force from textbooks
waves of kilometric heights would flush down the globe!

20 Elipsoid is perpendicular to the effective gravity force
„flatness” 1/297

21 Parabole is perpendicular to the effective gravity force

22 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

23 Ellipsoid vs. geoid i.e. geometry vs. physics
Geoid – constant (gravitational + centrifugal) potential surface

24 GOCE: equipotential lines

25 Earth’s shape: equipotential surface
± 100 m

26 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

27 What is the shape of Earth?
The one, shown by the lever (libella) and this is perpendicular to the vertical Poziomica, pion

28 Earth’s shape: horizontal water
because water level is always horizontal, like Copernicus said

29 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

30 What is the Earth’s structure?

31 What is the Earth’s structure?
crust ↔ litosphere mantello ↔ astenosphere G. Karwasz, J. Chojnacka, Geografia w Szkole, 2012

32 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.

33 What is the Earth’s crust?
Lampa Lava

34 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

35 Melting and solidifying
Lampa Lava

36 Quarz, olivine etc. Mg2SiO4

37 so, the vertical structure is getting complex

38 so, the vertical structure is getting quite complex...
Nature09401-f1.2.jpg

39 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

40 and the surface structure?
some 500 mln yrs ago

41 Moving continents + 50 mln yrs (?) wosk

42 Colliding continents (I)
John Nábelek, et al. Science 325, 1371 (2009); Foto: J. Karwowski, M. Karwasz, M. Visintainer

43 Colliding continents (IIa)
Westward: Japan Subduction angle: 45º Dwie kartki papieru

44 Colliding continents (IIb)
Eastward: Andes Subduction angle: 15-25º

45 Colliding continents (III)
Subduction of oceanic plates Physics World, no 3. (2012) Ryc. K. Konieczna

46 IV Continents drifting away
Foto M. Karwasz

47 IVa Continents drifting away
Foto M. Karwasz

48 Earth’s magnetic field
Dynamo model

49 Magnetic nigthingales

50 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

51 so, it is getting quite complex
Glatzmaier and Roberts 1995

52 Atmosphere: Coriolis force
Ω v -2Ω×v

53 Atmosphere: Coriolis force
Ω v -2Ω×v

54 Atmosphere: Coriolis force

55 Atmosphere: Coriolis force + rotation
High troposphere: Earth’s rotation Troposphere: Coriolis around the two Tropics

56 Atmosphere: Tropics and trade winds
Why Tropics are high pressure regions? subtropical and polar jet streams It is dry (descending) air!

57 Atmosphere: Columbus plan
Seasonal changes in Earth’s axis angle between September and March (1492/3)

58 Coming back to oceanic circulation
Chile (Humboldt)

59 Atmosphere: simple mechanisms, complex pattern

60 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

61 Wind-driven oceanic circulation
Northern hemisphere: clockwise, like Gulf stream, California Southern hemisphere anti-clockwise: Chile (Humboldt), Kalahari) antyzegar

62 In-depth oceanic circulation
Gulf Stream will stop if waters around Iceland warm up akwarium

63 Time-dependent patterns: Fourier components

64 Atmosphere (II): Fourier components

65 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

66 Homer: Scilla & Charybdis

67 In-between Scilla and Charybdis

68 Messina Strait 3 times a day!
Fontanna Herona, Fala w misce w przewężeniu

69 A bigger wave: tsunami

70 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

71 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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