FreshGadgetz Novelty nice Potato Clock Novel Green Science Project Experiment Kit kids Lab Home School Toy 1.The metal strips and potato make a simple battery that creates electricity to operate to operate the clock. Each potato works as a device called a electrochemical cell. Put some soft drink into the pots provided.Insert the copper and zice plates into the pots, as shown in the diagram. Taking care that the metal pates do not touch each other.The clock should now start to work. You may experiment with different liquids like salt water,fruit juices. Or fruit like lemon, orange,tomato etc.The fun is unlimited. Cup Size: 5.5cm x 5.5cm x 6.8cm - 2.17inch x 2.17inch x 2.68inch. Clock Size:6.7cm x 3.2cm x 1.2cm - 2.64inch x 1.26inch x 0.47inch.