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Invisible Ink Pen Experiment with McKeyla Doll
Now you can perform an experiment at home with Project Mc2™ leader, McKeyla McAlister™. Make your own invisible ink pen just using household ingredients like baking soda and water. Picking Up S.T.E.A.M. Your ink may seem invisible when you’re writing your secret message, but the pen is actually leaving a residue of sodium bicarbonate (aka baking soda). When you rub your paper with a berry or tea bag, the acid in those items creates a chemical reaction with the baking soda, a base. That reaction makes your message become visible.