The Radiometer and Its Composite Force  

L. I. Thompson

I call the radiometer force a composite force as it includes the deceleration of the rarefied gas molecules in transferring molecular momentum to give the net acceleration of the radiometer vanes. 

In a well balance radiometer the net force exerted could be transferring the molecular momentum to reach 2000 to 3000 rpm macro vane and harness momentum.  After the transfer of molecular momentum the rarefied gas molecules become  a dead weight until re-energized. In the complexity of the radiometer rarefied gas reactions is  the simplicity of the vanes and harness rotating in response to the input of energy.

The testing is in a partial vacuum of 100 to 300 microns. I use a 60w halogen light focused on various weight aluminum strips with carbon black on one side. The strips were holed to freely move on a horizontal rod.

With the weightier strips, after a little back and forth movement, the strips would bind on the rod. Yet I observed a 0.002 gm, 1 cm strip, holed on one end to hang on the rod, that the strip moved first with agitation and then energetically around and along the rod.  Though a small mass,  I found the centrifugal motion could  have a directional movement. This tending to confirm William Crookes' original observations. (1)

With limited equipment I do not take the testing further. As a proposal  I would next use a test "apparatus" with the "surfaces"  fixed to a light weight rod. The rod suspended with fine wires. This test would determine if the net force could be directed to propel such a light weight "apparatus" forward. 

The forward movement would be limited by the wire mounting. Yet I feel the confirmation of a forward movement opens the possibility the application of a net force might cause the acceleration of a body by using the inertia of a body itself (rather than the earth) as the "accelerative base". 

A study of the composite net force could include the energizing of the gas molecules and the deceleration phase of the  gas molecules to give the resulting net vane acceleration. (It would avoid a misconception of the transfer of molecular momentum to macro momentum.) It would explore the implied high molecular velocities across the vane surfaces. It would explore why there is little apparent offsetting back force in the acceleration of the vanes.   It would quantify the efficiency of the transfer of molecular momentum to macro momentum.

I feel this further study could bring clarity to the nature of the radiometer composite net force.

(1)  http://en.wikipedia.org/wiki/Crookes_radiometer , 2nd paragraph.

 August 24, 2015   lance@pon.net .