• Plastic vials with two holes cut in the lid.
  • A wooden holder or putty works to keep vials stable on work area
  • A pair of copper and zinc rods about 5 to 10 cm (2 to 4") long and 1/8" in diameter.
  • 1/8 cup each vinegar, salt water, coke and water.
  • A digital multimeter (NL)
  • A Christmas light bulb
  • A small buzzer
  • A small motor

Understanding simple batteries.

The juices in the fruit and vegetables are electrolytes (NL) . They allow chemical reactions to occur as acid does in a commercial battery. A battery with liquid electrolyte is often referred to as a "wet cell". A car battery is a wet cell.

Fix the vial in a holder or fasten it down with putty so it does not fall over.

Use the vial to make a battery with salt water and the metal rods. Measure the battery voltage.

Design and conduct an experiment to determine the effect of different liquids (used as electrolytes) on the voltage produced in a liquid battery.

Design and conduct an experiment (NL) to determine the effect of different liquids (used as electrolytes) on the voltage produced in a liquid battery.

Your experimental question is:

Define your independent variable (IV)
Define your dependent variable (DV)
What factors are held constant in your experiment?

State your hypothesis:
Design a data table. Conduct your experiment and record your data.

Graph your data.

Conclusions:

This activity concludes with the students designing another experiment to determine how well an electrical device such as a light bulb, buzzer or small motor functions with the different liquid-electrolyte batteries.


What is a battery? (NL)