Science Project Idea
Make Electricity From Saltwater

If you are asked to do a science project and you are looking for a good science project idea, this might be what you have been looking for. Making electricity from salt water is ranked among the 10 best science project ideas by a group of project advisors at ScienceProject.com. 

Life application:

We all know that the world is now facing an energy crisis and everyone is trying to do something about that. Some people try to use solar energy and wind energy; some others try to invade and occupy oil producing countries; and now you can show them that electrical energy or electricity can be made from air and saltwater. After all, both the air and the saltwater are freely available everywhere. These are the two things that we have plenty of them available in most areas.

This may seem impossible.

I could not believe it myself the first time that I heard about it. It almost sounds like a magic trick. Finally, I decided to test it anyway.

I tried different concentrations of salt water, different temperatures, and different electrodes and had no success. It took me a few months thinking about it until I solved the problem in my mind and decided to repeat my experiments again. This time everything worked fine and I was able to make enough electricity to light up a small light bulb.

The concept is easy. The same way that you burn wood and make heat energy, you should be able to burn metals and get electricity. The difference is that you are not really burning any thing; instead, you are producing a condition for oxidization which by itself is the same as slow burning. So what you really do is oxidizing iron in saltwater using the oxygen from the air or any other source. (At least, thatís my theory at this time)

I donít know if this system of producing electricity is economical and cost effective. What I know is that it is worth to try. If with one cup of salt water and some metals I was able to light up a small light bulb, maybe you can light up the entire building by a tank of salt water and a few hundred pounds of scrap metal.

No mater what is the results, you can be proud that you can make an emergency battery for yourself if you need it.

It took me a long time to make the first working battery using the salt water; however, you donít have to waste that much time. I have combined the results of all my experiments and made a recipe for success. Just follow the instructions below and you will get results in the first try.

Verified and approved by ScienceProject.com

This project idea is verified and approved by a group of project advisors at ScienceProject.com. It is ranked as a multi-level project that can be tried by students as young as 12 years old, up to the 4th year chemistry college students. At higher grades student may also study the movement of ions and the chemical reactions that cause the production of electricity in saltwater battery.

What is the cost of material?

Some people may already have all the materials at home or be able to get them free; however, if you choose to buy all materials, you may end up spending about $20 or more. 

A good Project title

Need an exciting and attractive title for your science fair project? You have many interesting choices with this project. Following are just a few samples:

  1. Electricity from air

  2. Electrical energy from chemical reactions

  3. Electricity from saltwater

  4. Air battery

  5. Saltwater battery

Introduction:

Batteries have been made with many different chemical compounds. Scientists often try to make batteries that provide more energy and last longer. Many of such high quality batteries are commercially available today. They are used in flashlights and electronic devices such as radios, watches, computers and calculators.

Making a battery is always an exciting science project. Your home made batteries can be used as chemistry, physics or electricity project. This project can be performed and conducted as a display project, engineering project or experimental project. In this project you will make a saltwater battery.

How the battery is made?

A battery is made of two different electrodes inserted in a chemical compound. A chemical reaction between the electrodes and the chemical compound produces electricity. For example if you insert a copper rod and an iron rod in a cup of orange juice, that will be a battery. In this example copper rod and iron rod are the electrodes and the orange juice is the chemical compound or electrolyte. The problem is that the electricity produced by such a battery is too little and has no practical use and you cannot use it to light up a light bulb. The saltwater battery described in this project guide can light up a light bulb for a few seconds or a few minutes. When the light goes off, you can simply recharge it by providing fresh salt water or providing additional air or oxygen. Simply empty the used salt water and add fresh salt water to get light again.

Does it really work?

Although a saltwater battery is not as strong as a commercial battery, it can produce visible light on a low voltage light bulb. It is also safer than batteries that use many harmful chemicals.

What chemicals do I need?

The only chemical that you need is Sodium Chloride (NaCl) also known as table salt. This is the salt that you usually have it at home and use for cooking. If not, you can buy it from grocery stores. Good quality, pure and inexpensive packages of salt are often marked as kosher salt. You also need water (H2O).

What electrodes I can use?

Some articles suggest using Aluminum and Copper metals as electrodes; however, I have not been able to verify that. I suggest using iron and magnesium electrodes. Of course you can test any combinations of metals that you like. Iron is widely available in the form of wires, nails, metal strips, steel wool and many more; however, I used steel wool because it has a larger surface in compare with others. If you want to use iron wires or strips, you may make a coil out of them to fit a larger surface in a smaller space.

Magnesium metal is mostly used in construction of airplanes and some automobile parts. Some magnesium alloys contain large amounts of aluminum. For this project you need pure magnesium or a magnesium alloy with more than 65% magnesium. Any broken piece of a magnesium part may be used as electrode. Pure magnesium electrode is not sold in stores; however, you can order them online from MiniScience.com.

Electrodes must be clean; so if you are trying to use a machine part as your electrode, you may need to wash them with warm water and dishwashing detergent prior to use. Any oil on the surface of electrodes can interrupt or prevent the chemical reactions and the electrical current.

Suggested List of material:

  1. Salt and water
  2. Iron electrode (Steel wool is good)
  3. Magnesium electrode (Flat or coil)
  4. Wire lids with alligator clips
  5. Miniature 1.2-volt light bulb (Low voltage)
  6. Miniature base
  7. Hydrogen peroxide

Procedure:

  1. Make a strong solution of salt (about 200 grams of salt per liter) in a deep plastic container (topper ware).

  2. Screw the light bulb in the base and connect one wire to each of the contacts on the base.

  3. Connect the open end of one of the wires to the iron electrode (Steel wool).

  4. Connect the open end of the second wire to the magnesium electrode.

  5. Insert both electrodes at the same time in two opposite ends of the plastic container. Make sure the electrodes are completely or mostly in the saltwater. At this time you should get a light in the light bulb.

  6. If you remove the light bulb and connect a DC voltmeter to the electrodes, you must see a voltage of about 1 (one) volt.

  7. To get more light, add some hydrogen peroxide (an oxidizer) to the saltwater solution.

Trouble shooting: 

If you are not getting any light, following are possible problems that can be verified.

  1. The light bulb is defective, improperly installed or requires much higher voltage. Test your light bulb with a AA battery and it should work.

  2. Check all the connections. Placing a AA battery between the electrodes must light up the light bulb; otherwise, at least one of the connections has problem. If you are using regular wire, make sure you have removed the insulation in all contact points. 

  3. The electrodes are very small or just a small portion of them is inserted in the saltwater.

Safety precautions:

After a few minutes of light production, the salt solution becomes alkaline. Alkaline solutions can irritate eyes and cause dryness of skin. Avoid contact with the used saltwater solution. Used saltwater can be disposed in the sink or sewer system along with other household liquid waste. If you add hydrogen peroxide to the solution, you must dispose dilute it with plenty of water before disposing it. Hydrogen peroxide is an oxidizer can can cause rust in metal pipes if it is not diluted.  

Why is it called air battery?

Batteries are usually known by their electrolyte or their electrodes. Although we call it saltwater battery (because it is using saltwater as the electrolyte); it also needs air or oxygen. Oxygen is needed in order to oxidize the iron and this battery will not work where no oxygen is available. Because of the important role of oxygen in this battery, some people call it air battery. 

Where can I buy materials?

The Magnesium Electrode is available at MiniScience.com, all other materials may be purchased locally. A kit for this experiment is available at klk.com or KidsLoveKits.com.

Photo and diagram are from ScienceProject.com website, printed with permission. This article is also available online at http://www.MiniScience.com/link