Remember that in a battery, electrons are leaving one metal strip and flowing to the other strip. Current is a measure of how many electrons are flowing in time. Electron current is a lot like a stream. A stream is the flow of water. Electron current is the flow of electrons.
Some metals make better batteries than others.
You will try to find the combination of metals that gives the most voltage and current. From now on, use this best combination of metals in making batteries. Potatoes in Series Make another potato battery. Wire up the two potatoes in series, as shown below. Think about voltage as the height of a hill.