SIGNIFICANT EVENTS - SCIENCE EVENTS
10/25/02
Fundamental Physics Experiment Resolves Controversy Regarding Helium Surface Tension
A controversy has existed in the physics literature about the correct value for the surface
tension of liquid helium, with different groups having obtained results for this important
quantity that differ by as much as 6%. To resolve this issue, the group at Brown University
headed by Humphrey Maris has developed a novel method to measure the surface tension utilizing
drop levitation techniques employed in their ground-based task. A drop of liquid helium is
levitated using the magnetic field from a superconducting solenoid. Oscillatory motion of the
isolated drop is then excited by means of an electrostatic drive and the frequencies of
different normal modes of oscillation are measured. From these frequencies, the surface
tension of the liquid helium in the drop can be determined with high accuracy. This measurement
settles the uncertainty about the correct value of the surface tension of liquid helium, with
the value they derive for the surface tension agreeing precisely with one of the published
results. Their paper "Surface Tension of Liquid 4He as Measured Using the Vibration Modes of
a Levitated Drop", with authors C. Vicente, W.-J. Yao, H.J. Maris and G.M. Seidel, has been
accepted for publication in Physical Review B and will appear this fall.
