The Let's Do Chemistry "Build a Battery" activity lets participants learn how batteries work and how materials behave, change, and interact by building their own simple battery out of metal and felt washers. Learners can use their battery to power an LED or a buzzer. This style of battery is similar to the original "voltaic pile" battery. Activity includes a facilitation guide with potential misconceptions, relevant science infosheets with real-world connections, table sign, and activity training video. All public-facing materials also available in Spanish.