A cell from two metals
Different metals in a liquid make electricity.
A cell from a lemon
A copper wire and an iron nail pushed into a lemon make a simple cell.
Where do you think the electricity comes from?
What this lesson covers
The idea
A Voltaic (Galvanic) cell has two rods, called electrodes, of different metals partly dipped in an electrolyte, usually a weak acid or salt solution; a chemical reaction between the rods and the electrolyte produces electricity.
A cell from a lemon
A copper wire and an iron nail pushed into a lemon make a simple cell.
Where do you think the electricity comes from?
- A chemical reaction between the metals and the juice
- The lemon is full of tiny batteries
- The lamp makes its own electricity
Build the cell
Choose the left rod, the right rod and the electrolyte. Make the lamp glow.
Two metals and a liquid
Two rods of the same metal gave no electricity. Two different metals in the liquid did. A chemical reaction between the rods and the liquid produced it.
A Voltaic (Galvanic) cell has two rods, called electrodes, made of different metals, partly dipped in an electrolyte, usually a weak acid or salt solution. A chemical reaction between the rods and the electrolyte produces electricity.
- Part | What it is
- Electrodes | Two rods of different metals
- Electrolyte | Usually a weak acid or salt solution
Notes
A Voltaic cell has two electrodes of different metals dipped in an electrolyte. A chemical reaction produces electricity.
Check yourself
The rods in a Voltaic cell are called …
The liquid in a Voltaic cell is called the …
What produces electricity in a Voltaic cell?
Which set-up makes a working Voltaic cell?
- electrolytes. The electrolyte is the liquid. The rods are the electrodes.
- electrodes — correct. Yes!
- filaments. A filament is the thin wire inside a lamp.
- electrode. The electrodes are the rods.
- battery. A battery is made of cells. The liquid is the electrolyte.
- electrolyte — correct. Yes!
- A chemical reaction between the rods and the electrolyte — correct. Yes!
- Heating the rods. No heating is needed. A chemical reaction produces the electricity.
- Rubbing the rods together. The electricity comes from a chemical reaction between the rods and the electrolyte.
- Two copper rods in a salt solution. The two rods must be made of different metals.
- A copper rod and a zinc rod in a salt solution — correct. Yes!
- A single zinc rod in a salt solution. A cell needs two electrodes made of different metals.