Does the Amount of Salt Matter When Conducting Electricity?

Data Analysis

Data Analysis Continued

Procedure

Conclusion

Results

Bibliography

Materials

Does the Amount of

Salt Matter When

Conducting Electricity?

By: Samuel Alderson

Hypothesis

The more salt (sodium chloride) content in a solution when used in an electrical circuit, the more power it will conduct.

Background information

Many people have contributed to the invention of electricity, but I found Alessandro Volta’s contribution to be the most interesting because he found electricity in inorganic means and discovered the very first electric cell.

Volta was inspired by Luigi Galvani who discovered electrical activity in the nerves of a frog he was dissecting. They disagreed on where electricity came from. Galvani thought electricity came from animal tissue and Volta thought it came from different metals touching in a moist environment. They were both right. Volta went on to invent the first battery, called the Voltaic Pile. It was constructed of cardboard soaked in brine (salt water) that was inserted in between alternating disks of zinc and copper which produced an electrical current, the first of its kind that was reliable.

Water is a poor conductor of electricity but adding salt to water makes it a good conductor of electricity. The process of passing electricity through a solution is called electrolysis. Salt in a solid form does not conduct electricity, but when mixed with water the solution makes a good electrolyte. Table salt (sodium chloride) is made of atoms that when dissolved are separated into positively and negatively charged ions. If you create an electrical circuit using a battery and you attach a wire to the negative post and put it in salt water, the positive ions will be attracted to it. Likewise, if you attach a wire to the positive post and put it in salt water, the negative ions will be attracted to it. This is how it carries an electrical current.

Since I don’t live near the ocean, I needed to find out how much salt was in seawater. I found that seawater contains 35 grams of salt per liter of water.

Gatorade Chicken Soup

Seawater Saltier Water

Experimental Design

The constants in this experiment were the battery, wires and alligator clips, temperature of all liquids and amounts of liquids.

The manipulated variable was the amount of salt in the various liquids. (I am aware that some of the liquids had additional elements, but for the purpose of this experiment the additional elements did not interfere.)

The responding variables were the amount of bubbles, the color change in the liquid, and the speed of the motor.

1.Gather the materials.

2.Weigh the salt.

a.Put the small glass bowl on the scale. Reset the scale to zero. Add salt until the scale reads 18 grams. Label and set aside.

b.Get another glass bowl, put on the scale. Reset the scale to zero. Add salt until scale reads 36 grams. Label and set aside.

3.Prepare liquids.

a.Measure and pour 2 cups of Gatorade in the medium bowl using the small measuring cup. Label as “Gatorade” and set aside. Wash measuring cup.

b.Measure and pour 2 cups of chicken noodle soup concentrate in the medium bowl using the small measuring cup. Label as “soup” and set aside. Wash measuring cup.

c.Pour room temperature water into the large measuring cup up to the ½ liter mark. Add the salt labeled 18 grams to the water and stir until dissolved. Label as “sea water” and set aside. Wash measuring cup.

d.Poor room temperature water into the large measuring cup up to the ½ liter mark. Add the salt labeled 36 grams to the water and stir until dissolved. Label as “extra salty water” and set aside. Wash measuring cup.

4.Set up the circuit.

a. Connect one end of a wire to the + (positive) post of the battery and the other end will go into the liquid. Just put it on the table for the time being.

b. Connect one end of the second wire to the – (negative) post of the battery and connect the other end to a connector to the motor.

c.Connect one end of the last wire to the other connector on the motor and the other end will go into the liquid. Put that end on the table for the time being.

5.Test each liquid.

a.Get the bowl of Gatorade and put it in between the two wires lying on the table.

b.Put the two ends of the wires into the Gatorade holding them so they won’t touch, preferably as far apart as possible.

c.Leave in for 2 minutes then remove the wires.

d.Record what you see.

e.Rinse the wires in plain water and dry with a paper towel.

f.Repeat steps a through e with the bowls of soup, seawater, and extra salty water.

6.Analyze the data.

Electric motor Circuit

Rusted Clips

Purpose

The purpose of the experiment was to determine if the higher the salt (sodium chloride) content in a solution when used in an electrical circuit, the more power it will conduct.

The information could be used if there was a shortage on materials that we use to conduct electricity, like copper wire. Also, it may be useful in the future for designing alternative energy.

1.“Experiments in Electrochemistry.” http://www.funsci.com/fun3_en/ electro/electro.htm Giorgio Carboni, January 1998

2.“Why Salt Water Can Conduct Electricity.” http://www.ehow.com/how-does_5245694_salt-water-can-conduct-electricity.html N.D. Isaiha David, ehow contributor

3.“The Effect of Water Salinity on Electrolysis.”

http://www.all-science-fair-projects.com/project1328_91_1.html 2012 N.P.

4.“Electrolysis.” http://www.bbc.co.uk/schools/gcsebitesize/science/add_ aqa_pre_2011/ions/electrolysisrev1.shtml N.D. N.P.

5.“Alessandro Volta (1745-1827).” http://inventors.about.com/od/utstart inventors/a/Alessandro_Volta.htm N.D. Mary Bellis, About.com Guide

6.“Alessandro Volta.” http://www.ieeeghn.org/wiki/index.php/Alessandro _Volta N.D. N.P.

I stated in my hypothesis that the more salt (sodium chloride) content in a solution when used in an electrical circuit, the more power it will conduct. I tested four liquids, Gatorade, chicken soup concentrate, seawater and a saltier water solution that was double the amount of the seawater to see if I could prove my hypothesis was true. They each contained different amounts of salt to see if more salt would conduct more electricity, therefore, producing more power. I began by gathering the materials, setting up an electrical circuit and using the different liquids to see if it would complete the circuit and how much power it would have. The Gatorade only produced a few bubbles but no other changes and the motor didn’t move. The soup produced foamy bubbles and a greenish black color and the motor didn’t move. The seawater produced many bubbles quickly, much more of the greenish black color and after a few seconds, the motor started to run. I noticed the motor ran faster as I moved the wires closer together. The saltier water produced just as many bubbles and colored water as the seawater but the motor started immediately and ran much stronger.

I recorded the results, which showed that my hypothesis was true. The more salt in a solution, the better it conducted electricity and the more power it provided.

I might have just used water with different amounts of salt instead of different types of liquid. I was interested is using the different things and it would have been cool if I could’ve said that you could run electricity through chicken soup, but I realize the experiment would have been accurate if I had just used water.

I did some more research discovering that the bubbles were produced from the electrolysis process. Electrolysis breaks down ionic substances into simpler substances when an electrical current is passed through them. The greenish black color was a result of oxidation caused by oxygen combining with a substance, like the metal the clip was made from at the end of the wire. Oxidation is what causes rust.

Small measuring cup (1 cup)

Large measuring cup (1 liter)

Small bowl, approximately ½ cup

4 medium bowls, approximately 3 cups or larger

Digital food scale

Table salt

1 liter of room temperature water

6 volt battery

Tape, masking or electrical

3 insulated copper wire, at least 8” long

Alligator clips (not necessary, but helpful)

Small electric motor

Spoon

Gatorade

2 cans of Chicken noodle soup

Paper towels

The purpose of the experiment was to determine if the higher the salt (sodium chloride) content in a solution when used in an electrical circuit, the more power it will conduct.

The following are the results after 2 minutes of each liquid:

The Gatorade showed only a few bubbles appeared on the negatively charged wire, but no other noticeable changes. The motor did not spin.

The soup showed more bubbles, looked foamy and a greenish black color appeared. The motor did not spin.

The sea water showed many bubbles, a greenish black color and a few seconds later, the motor started to spin. When I moved the wires closer together, the motor spun faster.

The saltier water immediately made lots of bubbles and the motor started to spin. The greenish black color happened about the same as the sea water. I noticed no difference in the speed no matter where I moved the wires in the bowl.

After testing all four liquids, I noticed that the end of the wire that was positively charged had rusted. I assume a chemical change was happening as a result of the electricity moving through the water.

I knew saltwater conducted electricity because my older brother did a science fair project when I was little and I thought it was really cool! I wanted to test something that would be much cooler than what he did. After much thought, I wondered if more really is better. I decided to test the theory that the more salt, the more power you would have.