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What happens when voltage is increased during electrolysis?Featured science projectScience project video


This science fair project was performed to investigate the relationship between the DC voltage applied to an electrolyte and the rate of hydrogen gas produced during the process of electrolysis.


Increasing the DC voltage applied to an electrolyte solution will increase the rate of release of hydrogen gas.

Scientific Terms

Electrolysis, electrolyte, ions, cations, anions, electrodes, anode, cathode


Electrolysis process

Electrolysis refers to a chemical process that occurs in an electrolyte solution when an electric current is passed through the solution. An electrolyte solution is made up of negatively charged ions - cations - and positively charged ions - anions. Cations and anions move freely in an electrolyte solution.

The electrolysis process takes place when the positive and negative terminals of a battery are connected to conductors called electrodes and immersed in the electrolyte solution. The electrode connected to the negative terminal is called the cathode and the electrode connected to the positive terminal is called an anode. When the cathode and anode are connected to the battery and immersed in the electrolyte, the negative ions (anions) will be attracted to and move towards the anode (positive electrode). The positive ions (cations) will be attracted to and move towards the cathode (negative electrode).

When the ions reach the surface of the electrodes the following reactions may occur.

  1. Deposits may start to form on the surface of the electrode.
  2. Gasses may be released from the electrodes.
  3. The product of the electrolysis process may be dissolved in the electrolyte solution.
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Complexity level:
Project cost ($):
Time required:
It will take an hour to set up the science experiment, and an hour to conduct it
Material availability:
Easily found at a hobby store.
Safety concerns:

Use only batteries. Do not connect to mains supply.  Conduct the experiment under supervision of a qualified person. Highly flammable gasses will be released. Ensure that protective gear is worn at all times.