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Atomic Clocks

1. Traditional and Modern Methods of Navigation

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In this mini-lecture, we discuss methods of navigation, focusing in particular on: (i) how to determine your latitude (North-South position) using traditional methods, such as determine the angle between the the Earth’s surface and a fixed star; (ii) how to determine your longitude (East-West position) using traditional methods, which is similar to that used for determining latitude except that the time of day is needed to account for Earth’s rotation; (iii) how to calculate the error in your position due to your error in time; (iv) some historical context on the Longitude Act of 1714; (v) modern navigation using satellites, which requires the clock on the satellite and clocks on Earth to be synchronised; (vi) an error calculation exemplifying the error in the distance between the Earth and the satellite; (vii) the clock’s ‘tick rate,’ or frequency, precision that is needed for accurate use of satellite navigation; and (viii) the global positioning system (GPS).


In this course, Professor David Wineland (University of Oregon) discusses atomic clocks. In the first mini-lecutre, we compare traditional and modern methods of navigation, where we see that precision in a clock’s ‘tick rate’ is essential for modern satellites and GPS. In the second mini-lecture, we discuss how a basic, mechanical clock (such as a pendulum clock) works, compare these clocks with atomic clocks, explain how to make an atomic clock with lasers/masers, and discuss why atomic clocks are so accurate and reliable. In the third mini-lecture, we introduce the concept of holding, or trapping, a single atom (or ion) and how this can be used to detect atomic transitions between the energy levels of the atom. The fourth mini-lecture discuses further effects on atomic clocks, notably gravitational-potential redshifts, and notes future uses of atomic clocks.


Professor David Wineland is the Philip H. Knight Distinguished Research Chair and Research Professor in the Department of Physics at the University of Oregon and was jointly awarded the 2012 Nobel Prize in Physics for devising methods to study the quantum mechanical behaviour of individual ions. In 1975, he joined the National Institute of Standards and Technology (NIST) in Boulder, Colorado, where he started the ion storage group and was a professor adjoint at the University of Colorado at Boulder. Professor Wineland and his group at NIST were able to place an individual electrically trapped laser-cooled ion in a superposition of two different locations. This permitted them to experimentally study fundamental physics, such as quantum mechanical behavior. This work led Professor Wineland and his group to make advances in quantum computing and atomic clocks.

Cite this Lecture

APA style

Wineland, D. (2022, January 12). Atomic Clocks - Traditional and Modern Methods of Navigation [Video]. MASSOLIT.

MLA style

Wineland, D. "Atomic Clocks – Traditional and Modern Methods of Navigation." MASSOLIT, uploaded by MASSOLIT, 13 Jan 2022,

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