Chemical Cells and Batteries
Your phone, laptop, and even that old TV remote all rely on chemical cells to work. These brilliant devices are surprisingly simple - just two different metals (called electrodes) sitting in a chemical solution (the electrolyte), connected by a wire.
Here's the clever bit: the metals react differently with the electrolyte, creating a charge difference between them. When you connect them with a wire, electrons flow from one electrode to the other, and boom - you've got electricity!
The voltage you get depends on how different your two metals are. Pick metals that are really different in reactivity (like zinc and copper), and you'll get more voltage than if you choose similar ones.
Quick Tip: Think of it like a chemical see-saw - the bigger the difference between your metals, the more "unbalanced" it gets, creating more electrical energy!