Читать книгу Planning and Executing Credible Experiments - Robert J. Moffat - Страница 31

How amazing is the human sensory system and what it enables us to observe! Trying to extract as much information using scalar measuring instruments is quite a challenge. The human sensory system is very complex, and its receptors are very well tuned to our environment. If our eyes were just a few decibels more sensitive, we could see single photons; if our ears were just a few decibels more sensitive, we could hear the Brownian motion of individual air molecules as they bounced off our eardrums.

Consider our sense of touch. Our machinists claim to easily detect surface roughness of 50 mils (1 μm) with work‐calloused hands. Can our body measure force? Can it measure temperature? We sense not temperature directly but heat‐transfer rate; if you've ever dipped a cold toe into a warm bath, did the water feel boiling hot even if was just warm? (As in an Onsen hot spring in Japan.) We don’t feel force directly but pressure and shear force. In contrast, in the lab we have simple instruments for measuring force and temperature but need sophisticated techniques to measure heat‐transfer rate. Even touch is a marvel. Prepublication we learned: in the journal Nature, it has been “experimentally established that humans have the capacity to perceive single photons of light” (Tinsley et al. 2016). Furthermore “human tactile discrimination extends to the nanoscale … within billionths of a meter” (Skedung et al. 2013). In part this explains how polished steel tactilely differs from smooth rubber.