Credit goes to my colleague Julia for sharing this interesting story from the recent ECS meeting in Cancún. I didn’t know about it before, but it turns out that 2.7 million people have watched this video explaining how you can test the charge in an alkaline AA battery simply by gently bouncing it upright onto a hard surface:
As it turns out, some scientists in the US came up with the explanation and presented the results at the conference. The long story short is that as the battery discharges, the anode essentially becomes more dense, which effects a change in the elastic properties of the battery. So, not only is the test true, but it appears it can be quantitative, and fairly accurate too!