What's in Water?

Poor Carson... His science fair is this week, and I've been so excited! He came up with a great project idea dealing with melting cups around a camp fire, but project set up required too much thought on my part. We'll save that one for next year.

This year I wanted him to understand a little bit about what I do at work, and he was working on his scientist award for Webelos. There was an idea for M&M Chromatography, and I was all sorts of ready to ah-hum "guide" the project selection.

Here's part of the report we put together. I don't think there's too much evidence that I was involved (I've also got stock in some great ocean front property in Central Wyoming if you're interested). I forgot to take a picture of his display board before he left for school today. I'll post one of him standing next to it at the science fair tomorrow.

Between this and his beans & cornbread deal, can you tell that I'm loving my son's 5th grade year?

Purpose
My mom and I read a newspaper article about some soil and groundwater contamination at Hill Air Force Base (Deseret Morning News, 2007). I was curious about how they found out how much contamination was present. Therefore, the purpose of my science experiment is to find the contents of groundwater. I would also like to find out how to determine the amount of pollution in groundwater.

Hypothesis
I think that a chromatogram will tell me which colors are mixed in water. (Carson missed 2 points on his journal because this wasn't a question. I had it out with his teacher - I can't submit a report to a client with question marks in it, so I completely disagree about this being a question. I lost the argument, so he got a final score of 98/100. However, I did get asked if I'd like to help judge the projects next year. :) )

Step by Step Procedure
1. Cut coffee filter into approximately 2-inch wide strips.
2. Staple a loop in one end of coffee filter strip.
3. Slide loop around a pencil.
4. Fill each cup with ½ cup tap water.





5. Put M&Ms in cups.
6. Let M&Ms sit in water until shell is no longer colored.
7. Stir water to mix colors.
8. Remove decolored M&Ms from one cup using slotted spoon.
9. Wash slotted spoon with tap water and Joy dish soap.
10. Rinse slotted spoon with tap water three times.
11. Dry with paper towel.
12. Throw paper towel away.
13. Repeat steps 5 through 9 for all cups.


14. Put pencil on rim of cup.
15. Adjust length of coffee filter strips to sit in water.
16. Let sit overnight.
17. Remove pencil and coffee filter strips.
18. Pour water down drain.
19. Throw away cups.



20. Scan or photograph paper strips.









Recorded Data
On January 5, 2008, I gathered all of the needed equipment. I was taking pictures of setting up the experiment, and the cup holding all of the M&Ms spilled on the floor. All of the M&Ms were picked up and placed back in the cup.

I separated M&Ms into 6 cups and then added water. The first thing I noticed was that the chocolate in the broken M&Ms was dissolving into the water. The second thing I noticed was that there was a different amount of water in each cup. I emptied the water from each cup and threw away the remnants of the M&Ms.

I started the experiment over using non-broken, non-cracked shell M&Ms and ½ cup of water in 4 new 16-ounce plastic cups.

After the color had dissolved off the M&Ms and I was mixing the colors, I discovered that if I used the same stirring spoon in each cup, it would mix colors from all cups. I used a new plastic stirring spoon for each cup to avoid mixing the contents. However, when I used the slotted spoon to remove the de-colored M&Ms, I did not have multiple slotted spoons.

My mom explained the difference between dedicated equipment and non-dedicated equipment. She told me that when groundwater samples are collected with non-dedicated equipment, the equipment must be decontaminated between uses. So, I used the slotted spoon to remove the de-colored M&Ms from Cup A. Then I washed the slotted spoon with tap water and Joy dish soap. I triple rinsed the slotted spoon with tap water. My mom told me that triple rinsing is standard procedure when collecting field samples.


After rinsing, I dried the slotted spoon with a paper towel. The paper towel was thrown away after each use.

After allowing the filter strips to sit in water for 2 hours, I noticed that the color at the top of each strip varied. I was not able to see whether the color combinations I’d placed in each cup had any influence on the colors on the filter strips.

After the strips had been in water for 6 hours, I noticed that blue was the color at the top of each strip. Strips A & B were placed in cups with the same mixture of colors, but the water traveled further up Strip A than it did Strip B.

Conclusions
Three cups contained known amounts of specific M&M colors. I assumed that based on the filter strips from the known cups I would be able to figure out what colors were in the unknown (Cup D). I know there were some blue and some yellow, but I was unable to determine if there were any red, green, orange, or brown.

I did not see a green stripe on any of the filter strips. I think this is because green is already a mixture of two other primary colors: blue and yellow, which both can be seen on the filter strips.

When I soaked the M&Ms in the water, the white “M” came off and floated on top of the water. I do not know why it did this, and I wonder if this had an impact on my chromatograms.

I located another article which describes the M&M chromatography process (Valparaiso, 1997). This article said that the M&Ms should only be left in the water until a little color has washed off. According to this article, leaving the candy in the water until it is cloudy results in a solution that contains too much sugar and will result in jagged spectrums on the filter paper. This is exactly what happened in my experiment.

I learned about using dedicated and nondedicated sampling equipment. Dedicated sampling equipment does not need to be decontaminated (decon’d). Non-dedicated equipment needs to be decon’d or you may get cross-contamination between samples.

I also learned about investigation derived waste. If I had been working with the PCBs and TCEs that lead to my experiment, I would not have been able to throw away the M&Ms, the plastic cups, the stirring spoons, the rinse water, the paper towels, or the water after the experiment was completed. It would need to be put in the proper container and disposed of in an appropriate location.

If I were going to do my experiment again I would do the following:
1. Use longer filter strips
2. Leave the M&Ms in the water for a shorter period of time
3. Do more controlled mixtures containing only 2 colors of M&Ms so that I could determine the order in which the colors should appear on the filter strip. Cup C contained only blue and red M&Ms. It is easy to see the order that they appear on the filter strip.

Finally, I learned about a chromatograph. This is a piece of laboratory equipment that generates chromatograms. The figure on the following page (we can't put this on the blog because it's in a format not supported by Blogspot) is a chromatogram of a sample that was analyzed for common volatile organic compounds, (VOCs). In this chromatogram, benzene is the first compound. This is similar to the blue dye on my chromatograms. I learned that using a chromatogram like the one on the next page, you can find the concentration of compounds by calculating the area of each peak.. I would have needed much more technical equipment to produce the VOC chromatogram!


Bibliography
Curran, 2004. Homework Helpers: Chemistry. Career Press. Franklin Lakes, New Jersey. Pages 17-19 and 295.

Deseret Morning News, 2007. Tests Uncover Mostly Low Levels of PCBs at Hill AFB. Wednesday, March 21, 2007. Accessed online.

Hill, 2008. Personal interview with Staci L. Hill, Professional Environmental Engineer. January 5, 2008.

U.S. Environmental Protection Agency (EPA), 2007. Groundwater Contamination. http://www.epa.gov/superfund/students/wastsite/grndwatr.htm. Accessed January 5, 2008.

Valparaiso, 1997. The Cause of Color. http://www.valpo.edu/organization/psme/labs/uv/CauseofColor.doc. Accessed January 7, 2008.

Wikipedia, 2007. Chromatography. http://en.wikipedia.org/wiki/Chromatography Accessed January 5, 2008.