Cells and Batteries Concept

Demonstrations in Cells and Batteries

Person holding metal electrodes connected via alligator clips to a yellow-cased BK Test Bench 388A multimeter displaying .402 V

Voltage of a Human

Holding dissimilar metal electrodes (copper and zinc) creates a galvanic cell using the body's electrolytes, producing ~0.4 V. Volunteers can be wired in series to add voltages or in parallel …
Potato with copper and zinc strip electrodes connected via alligator clips to a yellow Test Bench 388A digital multimeter reading 0.363 V DC, on white paper

Organic Batteries

Demonstrates electrochemical cells using everyday produce. Students see how zinc and copper electrodes in acidic fruit or vegetables generate a measurable EMF through redox reactions, connecting chemical potential energy to …
BK Test Bench 388A multimeter displaying .567 V, connected via alligator clips to zinc and copper electrodes draped over the rim of a beaker containing cloudy salt water

Salt Water Battery

A zinc-copper cell in plain water reads only 300-400 mV due to high internal resistance from poor ionic conductivity. Adding salt dramatically increases conductivity, and the measured voltage jumps to …
Glass jar containing blue copper sulfate solution with copper plates at the bottom and a zinc electrode at the top, connected to a yellow BK Test Bench 388A multimeter reading 0.980 volts
Safety

Gravity Cell (Crow's Foot Cell)

A gravity cell (Daniell-type cell) generates ~1.08 V from copper and zinc electrodes in density-stratified electrolyte solutions. Demonstrates how chemical reactions produce a stable EMF and how gravity keeps the …
Red Optima 12V battery with knife switch on terminals, connected via alligator clips to a round halogen headlight lamp glowing brightly
Safety

Car Battery and Headlight

A basic DC circuit: closing a switch on a 12 V storage battery lights a 3 halogen lamp. Demonstrates Ohm's Law, power dissipation, and energy conversion (chemical → electrical → …
6V dry cell connected in series with a variable resistor and two digital multimeters reading voltage and current; bottom panels show readings at three different resistance settings
Safety

Internal Resistance of a Battery

Shows that real batteries have internal resistance by measuring how terminal voltage drops as current draw increases. Students observe the quantitative relationship and see that batteries do not maintain constant …