About the lecture

In this mini-lecture, we discuss the properties of waves. In particular we: (i) use a model of an infinite number of masses connected by springs to understand longitudinal and transverse waves, as well as waves on a string; (ii) discuss the periodic motion of each bit of the string locally as well as the overall periodic motion of the string in space; (iii) introduce the wave number k and wavelength λ; (iv) explore the equation that describes the displacement of a wave as a function of space and time; and (v) define the wave velocity.

About the lecturer

Steven Balbus is the Savilian Professor of Astronomy at the University of Oxford and a Professorial Fellow at New College, Oxford. Before coming to Oxford, he was a Professeur des Universités in the Physics Department of the Ecole Normale Supérieure de Paris for nine years. He has also held academic positions at Princeton University, MIT, and the University of Virginia. Professor Balbus’ research interests lie in astrophysical fluid dynamics, particularly the behavior of magnetic gases. He has made distinguished contributions to our understanding of accretion disks, the dynamics of heating and cooling processes in hot plasmas, the behavior of gas in spiral galaxies, and the Sun’s internal rotation. In 2013, he was jointly awarded one of the highest honours in astronomy, the Shaw Prize, for his work on accretion disk turbulence, referred to as the magnetorotational instability. He received the Eddington Medal from the Royal Astronomical Society in 2020 and the Dirac Medal and Prize from the Institute of Physics (IoP) in 2021. Professor Balbus is a Fellow of the Royal Society and a member of the US National Academy of Sciences.