Measurements of the gravitational force on elementary particles have been done for electrons (F. C. Witteborn and W. M. Fairbank ) , bulk matter (R. V. Eotvos, D. Pekar, and E. Fekete) , (G. Roll, R. Krotkov and R. H. Dicke) , neutral particles of ordinary matter (J. W. T. Dabbs, J.A. Harvey, D. Paya and H. Horstmann) and photons (R. V. Pound and J. L. Snider). No direct measurements have been done for positively charged particles. An experiment (currently on hold because of lack of funds and equipment problems) is on the way in Cern (T. Goldman, M. V. Hynes and M. M. Nieto). This experiment will attempt to measure the free fall of antiprotons.
In this paper, we will show that there is a small residual electric field, due to electric dipoles, in all atomic matter. This electric field arises from the fact that two equal and opposite charges (such as a proton and it s electron cloud) generate electric effects that do not quite cancel, at distant points.
Since it is expected that mother earth generates a large amount of these electric fields, it is postulated that the outcome of free falling particle experiments in Cern, and the equipment used, are dependent - to some extent - on such fields. We will show that such fields may be difficult to shield, and as such, this information may be of interest to researchers and experimental physicists.