In this work the determination of electron number densities and electron temperatures for the case of a modified microwave plasma torch (MPT) operated at 100 W with argon by means of spatially resolved Thomson scattering measurements and photographic records of the MPT at different working conditions are reported. With an internal gas flow of 500 ml min - 1 and an outer gas flow of 200 ml min - 1 electron number densities and electron temperatures are in the range of 10 2 0 m - 3 to 10 2 1 m - 3 and of 16000-18000 K, respectively. When increasing the internal gas flow from 500 to 900 ml min - 1 the plasma becomes longer and the maximum electron number density increases by a factor of 2. An increase of the outer gas flow from 200 to 700 ml min - 1 leads to a lifting of the whole plasma from the burner edge with the maximum electron number density remaining unchanged. An increase of the power from 80 to 180 W was found to lead to higher electron number densities whereas the electron temperatures remain unchanged. The addition of 1.2 mg min - 1 of water vapor to the internal gas flow leads to a decrease of the electron number density from 4.7x10 2 0 m - 3 to 2x10 2 0 m - 3 and to an increase of the electron temperature from 16000 to 22000 K. In order to document the influence of the internal gas flow rate, water introduction and introduction of easily ionized elements on the visible plasma shape digitally recorded photos of the plasma are presented.