Physicist, mathematician and astronomer — Christiaan Huygens (The Hague, 1629 – The Hague, 1695) was a Dutch physicist, mathematician and astronomer, among the most important figures of the seventeenth-century scientific revolution. Raised in a wealthy patrician family and long active in Paris at the Académie des Sciences, he made fundamental contributions to mechanics, optics and astronomy. He is celebrated for formulating the wave theory of light, according to which every point of a wavefront acts as a source of secondary waves (Huygens’s principle), as an alternative to Newton’s corpuscular theory. He studied the motion of the pendulum and in 1656 invented the pendulum clock, greatly improving the measurement of time, and derived the formulae for centrifugal force and for the pendulum. In astronomy, using telescopes he had himself improved, he discovered Titan, Saturn’s largest moon, and understood the true nature of the planet’s rings.

Theories and contributions

  • Huygens’s principle — Every point of a wavefront is a source of secondary spherical waves; the new wavefront is the envelope of these waves, explaining reflection and refraction.
  • Centrifugal force — In uniform circular motion the acceleration is directed towards the centre: ac=v2ra_c=\dfrac{v^2}{r}.
  • Simple pendulum — Period independent of amplitude for small oscillations: T=2πLgT=2\pi\sqrt{\dfrac{L}{g}}, the basis of the pendulum clock.

Linked atoms

7 linked atoms.

04b Oscillazioni e moto armonico

05 Quantità di moto e urti

07 Dinamica rotazionale

16 Onde