Here is something we don't necessarily recommend you do, but we fully expect you to try anyway.
Take a battery and touch the knife blade to the battery's negative side. Now put the positive side to the tip of your tongue. Taste a bitter taste that almost vibrates? That battery is charged. Also, your brain has revolted and is tasting phantom things.
You're probably going to be more excited about the latter discovery, unless you need that battery for your flux capacitor or something equally important. What you experienced with the battery taste test is called electro-gustation, or a kind of electric taste that a current can stimulate us to sense. When it comes to perceiving food, electric taste presents many practical possibilities beyond a sour lunch of triple As.
One of those possibilities just became a reality. Researchers in Japan have introduced an electric fork that — when switched on — causes the eater to taste salt. Hiromi Nakamura is the researcher and engineer who invented the electric fork, and she points out that while we know electricity stimulates taste buds, there's not really a definitive answer as to how it works.
We do know that according to 2009 research, weak cathode current can inhibit different taste receptors. When the current reaches a higher voltage, the taste of salt becomes stronger. So by using a tongue and food to complete a circuit with the electrodes in the fork, the fork's tiny electrical stimulations tell the brain that salt is present, even if you're eating your mom's dry, tasteless chicken breast recipe.
The battery taste test actually heralded the discovery of electric taste. Johann Georg Sulzer was an 18th-century academic who wrote about pressing two touching metal plates to his tongue, which sparked a sour taste. (Incidentally, the observations also sparked the eventual invention of the battery, by Alessandro Volta.)
The electric fork, however, is hoping to solve some seriously contemporary problems. While there's debate about how much salt is too much in our diets, there is ample evidence that Americans are eating at least 1,000 grams or more than we should every day, and lowering intake would lead to lower blood pressure and cardiovascular risk. By commercializing the electric fork, we could eat bland foods with relish (or we could just eat relish) without increasing risk for health problems.
And like the battery you tasted as an appetizer, the fork can cause a little fizzy, vibrating sensation as well. Don't be alarmed; it's only the small current that's passing through the fork, food and tongue. Consider it even more fun for the senses.