Science Buddies: "Ask an Expert"

Okay I gues I must have misplace my forum topic but here is a gist of my project:

by soupea » Fri Dec 13, 2013 8:44 pm
Ok my project is about the effect of corroding metals due to acid rain on water quality and I have just now realized that it would take forever for results to show even if I start tomorrow. (my project is due around 1/3/13) And I'm really freaking out because its too late to change my topic...
I was planning on conducting the experiment by gathering one single type of water pipe that is commonly used in my area (Virginia). I was then going to concoct solutions of acids with varying pH types and place a pipe in each solution to see if they would corrode. I was going to allow two to three weeks of the pipe submerged in the solution. Then, I planned on taking tap water and allowing it to pass through each of the pipes. Then, I was going to measure the water quality with a drinking water test kit.
Is there any way to make this project work? Please answer

I have since conducted the experiment now but my results confuse me. The pipes have all physically changed but when I tested the water quality, the results were basically the same for all the different pH pipes that I tested. I'm really worried because I have to present next week and I don't know what to think of the results. Help please?

Hello Soupea,

So, it seems to me that you had 2 hypotheses embedded in this project. Let me know if I get this right.

1. pH of water in pipes (or type of acid in the solution eg citric, hydrochloric ...) will affect corrosion of pipes. More specifically perhaps, the lower the pH (more acidic) the more corrosion.
2. Corroded pipes will affect water quality of water that passes through them and the worse the corrosion the worse the quality.

Does this sound right? It seems like your results are consistent with at least the first half of hypothesis 1. As for #2, we need to know what the water test kit can detect and thus what we mean by water quality. If none of the compounds the test kit can detect are present in the pipes then it's no surprise the "quality" was not altered by corrosion. What kind of pipe did you use? Does it have lead in it? What does the kit detect? If the kit can potentially detect something leaching from the pipe itself and didn't then you have falsified your 2nd hypothesis. This is OK! This is why you do the work. Again, interpretation will depend on what the pipe is made of and what the kit can detect. After interpreting you can look forward and make a new hypothesis you might want to test in the future. For example, maybe water quality WOULD be affected by corrosion with a different type of pipe (based on the composition of the different kind of pipe and the definition of water quality in the test kit).

Cheers,
Colin

Thanks for replying!

Yes, you are right about my hypotheses. I had used common household liquids that were of different pHs (ie. distilled water, black coffee, vinegar, tomato juice, and lemon juice). After exactly a week, all the pipes showed signs of physical change although the ones with the lower pH showed greater corrosion inside, like my first hypothesis.

As for your questions about my 2nd hypothesis, I used copper tubes in the experiment. The kit I used to test the water quality tested the Total Chlorine, Copper, Nitrate, Nitrite, Alkalinity, pH, Hardness, and Iron. The results I gathered after testing were all within the EPA standards... Would I just report my conclusion as that? How should I show my results- in data or graph form?

Again, thanks so much! You've really helped clear out some confusion with my results.

Hi there,

So it looks like you have a handle on interpreting the results with regard to the first hypothesis. As for the second one, which molecules would you expect might have changed given that the pipes were copper? It might help to research the exact copper alloy used in the pipes to determine which compounds might be released from the pipes or produced as a product of reactions between chemicals present in your tap water (like chlorine) and leached chemicals from the pipes themselves. You can distinguish between things that did not change because there was no possible source for them in the water or the pipes, and things that could have conceivably changed but did not. You can make a hypothesis for future studies based upon this analysis. Why did nothing change? You might wonder whether water with different pH or chlorine content etc coming into the pipe after it is already corroded can affect what leaches from the pipe into the water. You might also consider how long the water sits in the pipe, or the temperature of the water or any number of other things. Drawing conclusions from the data and making hypotheses for future studies (even if you do not intend to do them) is part of the process.

You could present your results in a table of values or using some kind of graphical display. It's up to you. See what you think communicates the information in the clearest fashion.

Cheers,
Colin

Hey!

A few more questions here just regarding the setting up the board... should I seperate the analysis of my 1st hypothesis from my 2nd hypothesis? When creating my title, should I integrate both hypotheses in it?

Thanks for all the knowledgeable insight, you've been very kind!

P.S. Was this project below my grade level? I just want an honest opinion because I feel as if I'll get a low grade for doing something under my level even if it turns out well developed.

You can try to integrate both hypotheses into the title but it might make it too wordy. The title can be descriptive instead of stating the hypothesis, and that is what I would do unless there are rules that explicitly state otherwise. Then somewhere on the board you should state both hypotheses. I would discuss the analysis as pertains to the two hypotheses separately, then you can integrate it all in discussion, conclusions, implications, future directions and so forth (sections as relevant, not sure how your board should be structured).

As for grade level appropriateness, that's hard for me to say. Some of the chemistry of the possible interactions between the pipe alloy and tap water is fairly complex if you try to address it at all. Aging water infrastructure is a problem in many areas of the country, so that makes it relevant and important. A science fair project can have value even if you didn't invent a new way to screen for cancer or solve the puzzle of cold fusion. Hopefully you will get more out of doing this than just a grade (though I hope for your sake you do not get a bad one). Just try to take the most out of the experience you can. If you learn something then it has value, OK?

Good luck,
Colin

Yeah, you're right. Experience and knowledge are better than grades. I have learned a ton so far! Thank you for giving your time to help me out!

Heh one last question... Which title do you think is the most interesting or fully captures the topic of my project best?

The trouble with corrosion on water quality
Corrosion effects on potable water
The domino effect of pH on water quality

Thank you!!

I like the middle one, but my tastes tend to be dry and bland in titles. Scientists love to try to make catchy titles out of extremely dry material, so it's OK to try to spice it up within reason.
I would caution that the first and lasts titles imply results which you didn't see ... as there was no alteration of water quality. The middle one is still OK. How about something like "pH, corrosion, and potable water quality in copper water pipes". I can't think of anything clever myself. Sorry. If you make it cute, make sure it's still accurate. "Corrosion is pH-utile: robust potable water quality in copper pipes damaged by acidic liquids"?

Good luck.

I really like the last one you suggested! It's pretty clever! I'm probably going to just present the second clause as a question so as to not imply results like you said.

I'd say thank you in a million languages if I could, but for now thank you so much!