1. Why is the sky blue?

2. Apollo astronaut, Neil Armstrong told Patrick Moore in a 1970 BBC interview, "THE SKY IS A DEEP BLACK WHEN VIEWED FROM THE MOON. THE EARTH IS THE ONLY OBJECT OTHER THAN THE SUN THAT CAN BE SEEN, ALTHOUGH THERE HAVE BEEN REPORTS OF SEEING PLANETS. I MYSELF DID NOT SEE PLANETS FROM THE SURFACE OF THE MOON, BUT I SUSPECT THEY MIGHT BE VISIBLE". Apollo 11, July 1969

4. 1842 1842-1919 Rayleigh Scattering

7. We have three types of colour receptors, or cones, in our retina. They are called red, blue and green because they respond most strongly to light at those wavelengths. As they are stimulated in different proportions, our visual system constructs the colours we see. Response curves for the three types of cone in the human eye

15. + + + + + + Electric field + + +- Electron oscillator

16. + + + + + + Electric field + + +- Electron oscillator

19. 2 i  Dipole moment  (t) E y (t) = E 0 cos (  t) (t) (q 2 /m) i EyEy (t) Induced dipole moment,  =  E  = polarizability

20. 2 i  Dipole moment  (t) E y (t) = E 0 cos (  t) (t) (q 2 /m) i EyEy (t) Induced dipole moment,  =  E  = polarizability

21. Absorption ii rr Dipole moment in the excited state is larger compared to ground state (q 2 /m) i EyEy (t)  (t)

23.  Rotation of plane-polarized light

24. * *

25. Chirality

27. Circular polarization

28. Rotation of plane-polarized light

30. Absorption ii rr Dipole moment in the excited state is larger compared to ground state (q 2 /m) i EyEy (t)  (t)

31. Circular BirefringenceCircular Dichroism

32. Rotation of plane of polarization

33.  Rotation of plane-polarized light

34. Molecular Vibrations 1595 cm -1 3756 cm -1 3657 cm -1

35. Layout of Light Absorption Measurement I0I0 I Absorbance: A = log (I 0 /I) =  ∙c∙ L

37.  t  10 ns/ 100 MHz Mode-locked laser

38. Cavity Ring Down Spectroscopy Reflectivity = 99.99% τ 0 = 200 µs Path = 100 km

39. James Clerk Maxwell Born: 13 June 1831 Edinburgh, Scotland Died: 5 November 1879 (aged 48) Cambridge, England