Team of RussiaTeam of RussiaPresented by Nikita Shanin

Problem №17 «Vikings»:According to a legend, Vikings were able to navigate in an ocean even during overcast (dull) weather using tourmaline crystals. Study how it is possible to navigate using a polarizing material. What is the accuracy of the method?

Plan of solution

Problem analysis

Theory research

Checking of the model in practice

Method’s accuracy estimation

Physical model of the phenomenon

Conclusion

Nikita Shanin IYPT 2011 2

Polarized materials

Nikita Shanin IYPT 2011 4

Polarization of light wave

– unpolarized wave

– plane-polarized (linearly polarized) wave

Nikita Shanin IYPT 2011 5

Polarization methods

Initial wave

Final wave

Filter

transmission plane of linear polarizer

Oscillation’s direction

Nikita Shanin IYPT 2011 6

1

2

Polarization methods

Initial wave

Scattering medium

Plane-polarized wave

Nikita Shanin IYPT 2011 8

Dipole radiation

1

Polarization methods

Initial wave

Scattering medium

Nikita Shanin IYPT 2011 8

Dipole radiation

Physical model

To identity the circle, which passes though a point of sun and arbitrary point:1. To analyze the arbitrary point using filter and to find the darkest filter position2. Perpendicular to oscillation plane shows the required circle

Nikita Shanin IYPT 2011 9

HSB model

Hue – vary from 0° up to 360°

Saturation –, vary from 0 up to 100

Brightness – vary from 0 up to 100

Nikita Shanin IYPT 2011 10

Checking of the model in practice

Nikita Shanin IYPT 2011 11

Checking of the modelin practice

Nikita Shanin IYPT 2011 12

Sun positiondefinition

Nikita Shanin IYPT 2011 13

Observation duringovercast weather

Nikita Shanin IYPT 2011 14

Observation during overcast weather

Nikita Shanin IYPT 2011 15

Method’s accuracy

Nikita Shanin IYPT 2011 16

Brightness 49

Brightness 52

Conclusion

It’s impossible to navigate according this method during overcast weather

Error of sun position detection amounts to about 27 degrees

Nikita Shanin IYPT 2011 17

Reference

Мякишев. Физика: Оптика 10-11 кл. 4-еизд. М:Дрофа, 2002; 480с.

Viking navigation hypothesis under foggy and cloudy skies requires more light (physorg.com, February 27,2007), www.physorg.com/pdf91798327.pdf

Leif K. Karlsen: Secrets of the Viking navigators (nordskip.com), http://www.nordskip.com/vkarlsen.html