fixing by thinking: the power of dimensional analysis

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FORTH, E.N. Economou FIXING by THINKING: FIXING by THINKING: The power of dimensional The power of dimensional analysis analysis E.N. Economou E.N. Economou Dept. of Physics, U of C Dept. of Physics, U of C FORTH FORTH March, March, 200 2006 In the atomic idea “there is an enormous amount of information about the world, if just a little imagination and thinking are applied”. R.P.Feynman

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FIXING by THINKING: The power of dimensional analysis. E.N. Economou Dept. of Physics, U of C FORTH March, 200 6. In the atomic idea “there is an enormous amount of information about the world, if just a little imagination and thinking are applied”. R.P.Feynman. - PowerPoint PPT Presentation

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Page 1: FIXING by THINKING: The power of dimensional analysis

FORTH, E.N. Economou

FIXING by THINKING:FIXING by THINKING:The power of dimensional The power of dimensional

analysisanalysis

E.N. EconomouE.N. Economou

Dept. of Physics, U of CDept. of Physics, U of C

FORTHFORTH

March, March, 20020066

In the atomic idea “there is an enormous amount of information about the world, if just a little imagination and thinking are applied”.

R.P.Feynman

Page 2: FIXING by THINKING: The power of dimensional analysis

1.1. ATOMIC NATURE OF MATTER (& FORCES)ATOMIC NATURE OF MATTER (& FORCES)

2.2. WAVE/ PARTICLE DUALITYWAVE/ PARTICLE DUALITYQUANTUM QUANTUM MECHANICSMECHANICS

(a) Heisenberg Principle:(a) Heisenberg Principle:

(b) Pauli Principle:(b) Pauli Principle:

(c) “Schrödinger” Principle:(c) “Schrödinger” Principle:

3.3. EQUILIBRIUM STRUCTURES EQUILIBRIUM STRUCTURES MINIMIZATION MINIMIZATION OF (FREE) ENERGY (M.EOF (FREE) ENERGY (M.E))

2

x kin 2/3x p E 4.87

2 mV

2 2/3

kin,t 2 /3

V NV E 2.87N

N / 2 mV

2

1 GROUND 2/3mV

kin 1/ 3

cE 3

V

t

1/ 3

kin,t 1/ 3

cNE 2.32N

V

oror

oror

Page 3: FIXING by THINKING: The power of dimensional analysis

NEEDED ALSO:Strong force: range 1 – 4 fm, strength 1 –

100 MeV

Weak force: ,

Em force:

Gravity:

AND THE NUMERICAL VALUES OF , , , , ,

en p e ep n e

2 /e r

2 /Gm r

em e c G 0.8pr fm

Page 4: FIXING by THINKING: The power of dimensional analysis

Mass of proton & neutron is Mass of proton & neutron is the the

kinetic energy of the quarkskinetic energy of the quarks2 2 2

1/3

32 2p u d

cm c m c m c

V

2 2 21/3

32 2n u d

cm c m c m c

V

34

3 pV r

0.8pr fm;

2 917 13 3pm c Exp. 938.27

2 917 14 5nm c Exp. 939.57

Page 5: FIXING by THINKING: The power of dimensional analysis

Nuclei: A=N+ZNuclei: A=N+Z Strong Interactions: Strong Interactions:

Coulomb Interactions:Coulomb Interactions:

Kinetic Energy:Kinetic Energy:

v nn s s nn s v s nn nn nn1 1 2

A A V A A΄ V ; A A A , A΄ , A 82 2 3

2 2 2/3s 0 sA 4 R / α , V 11 MeV

21 e 3

Z Z 12 R 5

2/3 2/3 2

22/3

Z NZ N 2.87 ΄́

2 2 mV

22 2 2/3nucleus p n 1/3

e / e1

: Zm c Nm c 0 e / 0

0 / 0

3/ 4

3415.5, 16.8, 0.72, 23,

Page 6: FIXING by THINKING: The power of dimensional analysis

FROM ATOMS TO ASTEROIDS THE FROM ATOMS TO ASTEROIDS THE POTENTIAL ENERGY IS CHARACTERISED BYPOTENTIAL ENERGY IS CHARACTERISED BY

THE KINETIC ENERGY IS CHARACTERISED THE KINETIC ENERGY IS CHARACTERISED BYBY

ANDAND

INSTEAD OF USEINSTEAD OF USE

OTHERS:OTHERS:

e

em

αα

e 0 0 0

m c P Tm ,c,P,T,... , , , ,...

m P T

ee, ,m

2 2

0 0 05 2e Be e

1, P ,

m α km α m α

2

e B 2e

,m ,αm e

αα r f α

Page 7: FIXING by THINKING: The power of dimensional analysis

AtomsAtoms

αr f α α0.6 f 5d d,

2 2α

αα B

e e

r f α

, α0.5 η 1d d

ffαα increases as we move down the columns increases as we move down the columns of the P.T.E.of the P.T.E.ffαα local minimum for completed p and s/d local minimum for completed p and s/d orbitalsorbitalsffαα local maximum for , local maximum for ,

1ns 1np

Page 8: FIXING by THINKING: The power of dimensional analysis

Local Maxima for completed p, s/d orbitals Local Maxima for completed p, s/d orbitals

Local Minima for completed p, s/d orbitals plus 1Local Minima for completed p, s/d orbitals plus 1

Page 9: FIXING by THINKING: The power of dimensional analysis

MoleculesMolecules

α1 α2 α1 α2 Bd r r f f α exception: noble exception: noble gasesgases2

B me

Ed

e e0

α α

m m΄ E

m m 0,8 1,8d d,,

2e e

r r 02α αα1 α2

2 m mE

I m mf f

r0,5 1d d,,

2

0 2e

E 27.2 eVm α

Page 10: FIXING by THINKING: The power of dimensional analysis

SolidsSolids 3

s4 V

f3 N

3B3

3 ss

m A2.68 g / cm

4 fr3

2

s s s2 2 2e s s s

27.2 eV 625 calE

atom molm r f f

s 1 ,,

211 2 11

s s5 5 5 2e s s s

294 180 NB c c 10 N / m 10

m r f f m

,, sc 0.6

e0 s

e s α s

m 82 Kmα

m r m sf

sα 1.6,,

Page 11: FIXING by THINKING: The power of dimensional analysis

SolidsSolids

3 2

s 5 5s e

2 10

100 f m α

oD 2

s B

9000K

f A

sB s0.1 β 1d d,,

Page 12: FIXING by THINKING: The power of dimensional analysis

Comparison with experimental dataComparison with experimental data

4,874,876,486,483,853,853,933,935,285,285,685,684,114,114,634,63 (Κ(Κm/s)m/s)

0,540,540,9980,9981,291,291,371,370,730,730,7220,7221,291,291,681,68B (B ( ))

2,692,694,634,633,823,823,493,493,043,043,393,393,823,824,284,28 (eV/atom(eV/atom))

2,362,362,332,339,019,018,968,962,732,732,792,797,927,927,867,86((gr/cmgr/cm33))

3,183,182,672,672,992,992,672,67

TheoryTheoryExpExp..TheoryTheoryExpExp..TheoTheoryry

Exp.Exp.TheoryTheoryExp.Exp.

SiSiCuCuAlAlFeFe

f

11 210 / mN

Μρ

δΕ

Page 13: FIXING by THINKING: The power of dimensional analysis

FLUIDSFLUIDS

Sea wavesSea waves2

g,k ,d, ,

3

2 kgkf kd

,, f kd 1 kd 1

kd kd 1, tsunami

f kd tanh kd2

w 0.074 Jm

Page 14: FIXING by THINKING: The power of dimensional analysis

nn nn

2

1A΄

22 r

wr f α

nn1

0.45 eV / molecule2

nn 8

nn΄ 5

wf = 3.64

2

J0.1

m exp: 0.073 J/m2

Page 15: FIXING by THINKING: The power of dimensional analysis

WINDWIND INDUCEDINDUCED

TSUNAMTSUNAMII

λ(λ(mm))

1010-3-3

101000

101011

101022

101033

101044

101055

1010-2-2

1010-1-1

1010-1-1

101000

101022

101011

ph

ωυ = m/s

k

0.2320.232

0.84 0.84 km/hkm/h

1.7 cm1.7 cm

σk

ρg

k gd

Page 16: FIXING by THINKING: The power of dimensional analysis

FLUIDSFLUIDS

Drag forceDrag force , , , 2

α 1F c S ,,2S , LARGE BODIES, HIGH , LARGE BODIES, HIGH

SPEEDSPEEDη 2F c ,, 2c 6 R , SMALL BODIES, LOW , SMALL BODIES, LOW

SPEEDSPEEDαF

ReF /

Reynolds Reynolds numbernumber

watwaterer

0.010.01 0.010.01

airair 0.000180.00018 0.150.15

1 1gcm s 2 1/ cm s

Page 17: FIXING by THINKING: The power of dimensional analysis

Pr essure time

12

c

16e

2 22 2 2αe Β s w

m 4.13 10 1c c

m 18 1823m α f f

132c 1.72 10 rad / s

931 1

132 2

c 2.44 10 kg c kg2 0.89 10

c ms c ms1.72 10

exp:3 kg

10ms

Page 18: FIXING by THINKING: The power of dimensional analysis

Black Body RadiationBlack Body Radiation BS, c, , k T

422 2 SB S

SUN s s2 2 3

B B

k Tk TI 4 R 4 R

60 cck T k T

422 E

E s 2 3

k TI 4 R

60 c

Page 19: FIXING by THINKING: The power of dimensional analysis

Typical Planet: ETypical Planet: EGRAVITATIONALGRAVITATIONAL Ε ΕELECTRICELECTRIC

α u uM = N Am mv

11 333 3

α α

4 4R N r R = N r = N / A r

3 3

v

51 6ΓN 3,59 10 R 6,378 10 m v

2 2

a

2

4

GM eN

R f re

Β

3η , γ 2, f 2, r = fα

5

3322

51v 2 A 55

G

2 1N 2,8 10

f A

12

6

A 55G

3,65R 3,9 10 m

A

Page 20: FIXING by THINKING: The power of dimensional analysis

Why Earth is round?Why Earth is round? Why are there mountains?Why are there mountains? What is the largest possible height of a mountain in a planet?What is the largest possible height of a mountain in a planet?

When the shear stress exceeds the critical valueWhen the shear stress exceeds the critical value

c

S

B V g 1

V SH3

3 3

3 m

4 f

2g GM / R34

M R3

23

c 5 5e

2 10m f

322 2

B G

RH 0,025f0,3 10

α A

11 2RH 10 m

,

Page 21: FIXING by THINKING: The power of dimensional analysis

PlanetsPlanets

348

, min 3 3Β

R AN 10 N

f α

v

6minR 10 m (R 10H) t

55 56, max ,min,αστροN 2 10 N 2,3 10v v d

13

8 vmax Β

NR 10 m R fα

A

Jupital:

Pluto:

54 7N 1,14 10 , R 7,15 10 m v

48 6N 8,9 10 , R 1,15 10 m v

55 551.3 10 8.5 10BD ƒ ƒ

Page 22: FIXING by THINKING: The power of dimensional analysis

STARSSTARS MINIMUM NUMBER OF NUCLEONS:MINIMUM NUMBER OF NUCLEONS:

MAXIMUM NUMBER OF NUCLEONS:MAXIMUM NUMBER OF NUCLEONS:

NUMBER OF NUCLEONS IN OUR SUN:NUMBER OF NUCLEONS IN OUR SUN:

MAXIMUM NUMBER OF NUCLEONS IN A WHITE MAXIMUM NUMBER OF NUCLEONS IN A WHITE DWARF:DWARF:

3/ 4 3/ 257u

,mine G

mN 0.6 0.23 10

m

ν

3/ 259s

,maxG

N 1.3 10

ν ,, s 15

571,2 10

3/ 257

G

11.775 1.71 10

Page 23: FIXING by THINKING: The power of dimensional analysis

T

11

Z

02R

KIN B1

E2

E

0

2

B3 GM

5 RE

Tign

2 2

KIN e F B3 3

E N E k T5 2

2/322 e

Fe

N3

2m VE

0R R

Tmax

42 44/3e u

max e2eB

0,06 G m m NT N

Nk

4

uign 2

B

e mT 0,1

k

max ignT 2T

STARSSTARS

ΜΜminmin

Page 24: FIXING by THINKING: The power of dimensional analysis

G kin phP P P

phG kinE1 2 E 1

3 V 3 V 3 V

E

total G ph kinE E E E 0

STARSSTARS

ΜΜmaxmax

For large mass, T becomes large, EFor large mass, T becomes large, Ephph dominates over Edominates over Ekin kin thenthen

Page 25: FIXING by THINKING: The power of dimensional analysis

s 2

2GMr

c 2

s

1 GMmmc

2 r

1.1.

2.2.

3.3.

4.4.

3

Bs

1 c ck T

4 r 8 GM

2 42 2 4 3 3 B

s 0 3 2

k cdU c dM 4 r T dt M M t

G10 8

3130 0t 2,63 10 M kg years

2 35s P2 3

B P

S A GdU TdS , A 4 r , 1,62 10 m

k 4 c

Black Holes

Page 26: FIXING by THINKING: The power of dimensional analysis

UniverseUniverse Homogeneous & IsotropicHomogeneous & Isotropic

Expanding according to Hubble’s law:Expanding according to Hubble’s law:

Eucledian geometry Eucledian geometry ((as a result of inflationas a result of inflation))

11stst LAW (for dS LAW (for dS0): dU=d(0): dU=d(εεV)=-pdVV)=-pdV

Three unknown functions:Three unknown functions: R(t), R(t), εε(t), p(t)(t), p(t)

dR= R = H t R

dt

22

κιν G kin G

3 3 GME = MR , E , E E

10 5 R

2

22

R 8πGH = ε

R 3c

(1)(1)

2

R 4πG= - ε + 3p

R 3c

(2)(2)

Page 27: FIXING by THINKING: The power of dimensional analysis

OBSERVATIONSOBSERVATIONS

WMAP WMAP Wilkinson Microwave Anisotropy ProbeWilkinson Microwave Anisotropy Probe

Page 28: FIXING by THINKING: The power of dimensional analysis
Page 29: FIXING by THINKING: The power of dimensional analysis
Page 30: FIXING by THINKING: The power of dimensional analysis

the equivalent of 6 protons perthe equivalent of 6 protons per m3

This density equals to the critical one with an uncertainty This density equals to the critical one with an uncertainty of 2%of 2%

protons per protons per mm33, i.e. about , i.e. about 4.2%4.2% of of εε

The Rest DARK MATTER

DARK ENERGY

272 3

Kg9.47 10

c m

nucleons2

1

4c

ph2

0c

21.5%

c

v d

21 4%

73 4%

Page 31: FIXING by THINKING: The power of dimensional analysis

accelerated expansionaccelerated expansion todaytoday

forfor

forfor

nucleons ph dm dee ν

nucleons ph dm de dep p p p p p w ν ,, 1 w 0.73 d

d2 2 2

R 4 G 4 G 4 G3p 3 w 3 0.73 w 1 0

R 3c 3c 3c

R t t , 2.5

270 y t 7Gy

3 d d

inf1

t t 70 y2

d d

phRT const

nucleon ph de3 4

1 1, , const

R R

Page 32: FIXING by THINKING: The power of dimensional analysis

BB

t

q→B P,n→nuclei

εph→εnucl decoupling

Protostars

Galaxies

R 0 Today10-

4s1s

70 ky

380 ky

180 My

8 Gy

13.7 Gy

500 My