  The low-lying neutral excitation spectrum of the incompressible quantum Hall
fluid at $\nu=5/2$ is investigated by inelastic light scattering. Gapped modes
are observable only in a very narrow filling factor range centered at 5/2 at
energies that overlap estimates from transport activation gaps. The modes are
interpreted as critical points in the wave-vector dispersion of excitations
that preserve spin orientation. For very small changes $|\delta\nu|\lesssim
0.01$ the gapped modes disappear and a continuum of low-lying excitations takes
over indicating the transition from an incompressible fluid at 5/2 to a
compressible state. Observations of spin wave modes indicate spin polarization
of the 5/2 and 2+1/3 quantum Hall fluids.
