Feature: 100% Brand new and high quality. Ideal for fun learning. Comes with everything needed to experiment with green energy. Includes digital clock, light bulb, zinc / copper plates, wires etc. You may experiment with different fruit like lemon, orange, tomato etc. Spec:Condition: Brand newColor: As picture Material: Plastic + Metal Length of wire: Approx.15cm / 5.9 inch (Approx.) Size of zinc / alloy plate: Approx.1*4cm / 0.4*1.6 inch (Approx.) How it works: 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. It converts the chemical energy stored in the metal strips intoelectrucal energy.Two potatoes are needed to make electricity strong enough to run the clock. 2.A cell works because of the chemical properties of the metals inside (in this case the copper and zinc). The different properties cause tiny particles charged with electricity . (called ions) to move between the the two strips of metal. This flow is an electric current. The potato contains the particles that allow the current to flow,but it stops the metals touching. Electric current also flows along the wires between the zinc and copper strips and the clock. This current makes the clock work. 3. The potato chip can be replaced by other fruits such as lemon, orange an