3 ms·

Actually, if you read the article, they mention using two probes made of the same metal to eliminate any current generated by the differences in redox potential

• ars 17y ago
  There is still a difference. The probes are placed in different things, so the two probes have differing ability to oxidize. Oxidation of a metal is a much more likely source of electricity than a tree, so much so, that they need a much better experiment before I'll be convinced that the tree is making electricity. For example, let it run for a long time and check for any evidence of corrosion. Are there metals that don't corrode? Perhaps palladium? They could also try a variety of different metals for the probes (both at the same time) and see if they get different voltage readings.