We describe an experiment in which cold rubidium atoms, confined in an elongated magnetic trap, are excited
by transverse oscillation of the trap center. The temperature after excitation exhibits resonance as a function of
the driving frequency. We measure these resonances at several different trap frequencies. In order to interpret the
experiments, we develop a simple model that incorporates both collisions between atoms and the anharmonicity
of the real three-dimensional trapping potential. As well as providing a precise connection between the transverse
harmonic oscillation frequency and the temperature resonance frequency, this model gives insight into the heating
and loss mechanisms and into the dynamics of driven clouds of cold trapped atoms
