Unfortunately I never really could talk much with him about physics: first I was too young to understand him, and later he was too old to understand me - because his hearing was so bad, not because he wouldn't have understood what I was doing. In my first year as physics student, I did a numerical computation for him which lead to a small publication, but I didn't really understand what I was doing at the time! Today, with more understanding, I don't believe the conclusions in that paper are correct at all. Anyway, perhaps I would have studied something different if it hadn't been for his example (the rest of my family consisting of medical doctors - shudder!). My grandfather was famous for something known as the Fierz transformation in quantum field theory. Since I'm only an experimental physicist myself, I have no idea what it is good for :-)
A picture of Markus Fierz in 1936. Hi-res tif version (6.5MB)
Markus and Menga Fierz at their wedding. The children on the picture are Menga's youngest (half-)siblings, Röxli and Thomi Biber. Hi-res tif version (10.0MB)
A picture of Markus Fierz in 1970. Hi-res tif version (7.3MB)
After my grandfather's death, I received a couple of audio tapes with lectures on the history of physics, held during the winter semester 1972/1973 (in German of course). I have digitized them; unfortunately, the result is not very good - the tapes are very old, and I have no experience in digitizing audio. Of the 14 lectures, one is missing, and two are incomplete. The remaining 11 lectures are complete.