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Sodium Battery with a HUMAN Salt Bridge Description A 3 Volt Battery is made using sodium metal and copper metal, and... the audience! Explanation A simple laboratory battery that produces a volt or so can be made using two beakers with copper metal in copper sulfate solution and zinc metal in a zinc sulfate solution, IF we remember the "salt bridge" (A typical laboratory salt bridge is a bridge shaped tube that has a concentrated salt - like potassium chloride - that acts as an electrolyte. The salt bridge provides a conducting path between the two compartments of the electrochemical cell (battery)). But in this case, the bridge can be can be a piece of soggy filter paper or an inverted victory sign made with a human hand or anything else that contains mobile ions - like people!
Although it's cool to show a battery made from chemicals - in our natural greed for MORE VOLTAGE, we now shun the zinc and propose a more reactive metal: sodium! First we place a tiny speck of sodium (Na) in some water (with an acid-base indicator like phenolphthalein) and show how outrageously reactive it is! Since we can't put the metal in contact with liquid water (too reactive!), the sodium-copper battery must be made by putting the sodium metal in contact with the nervous fingertips of your friendly Chemistry Demonstration Guy’s right hand. Next, somebody grips his left hand, and everybody else who dares can join hands to make the human salt bridge. The volunteer at the far end of the salt bridge dips their pinky into the copper half-cell. If all goes well, we have a battery made from sodium, copper and PEOPLE good for about 3 volts.
Finally friendly Chemistry Demonstration Guy had better wash his fingers with vinegar right away to get rid of the sodium!still have questions? email us! explanation furnished by Colorado College's Dr. Ted Lindeman
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