Help with an Experiment Concerning a Copper Sulfate

[Andrew333]

Homework Statement

What I need some help on is whether copper sulfate can or should have been used in order to test the effects that copper has on the plants.

Relevant Equations

N/A

Hi, I'm in 12th grade and for my senior project I am doing an observation on the effects copper would have on plant growth. I have used copper sulfate to create increasing concentrations of copper in which I used to water my test plants.
After further research of lately, I found that copper sulfate not only has copper but I've read that it contains sulfur as well. I believe this would ruin the purpose of my experiment as the sulfur may effect the plants.
I would appreciate any assistance someone may have who is more knowledgeable on this topic than I am.
Thank you very much.

 

[symbolipoint]

After further research of lately, I found that copper sulfate not only has copper but I've read that it contains sulfur as well. I believe this would ruin the purpose of my experiment as the sulfur may effect the plants.
I would appreciate any assistance someone may have who is more knowledgeable on this topic than I am.

SULFATE for sure; but best I could guess, very little sulfur. Could the chemical supplier of your in-stock copper sulfate give you the quantity of actual non-compound SULFUR in the copper sulfate product? What I am saying included is, do not confuse SULFATE with SULFUR.

Your experiment or project seems in fact to be testing the effect of copper sulfate on plant growth.

 

[Nik_2213]

Are you using a traditional 'vine dusting' mix that contains both copper sulphate (hydrated) and powdered sulphur ??

Gotta ask as, long ago, my father mixed a batch of his own, but managed to set a portion alight...
Luckily, NOT indoors !

 

[NascentOxygen]

Hi, I'm in 12th grade and for my senior project I am doing an observation on the effects copper would have on plant growth. I have used copper sulfate to create increasing concentrations of copper in which I used to water my test plants.

Your method is correct. Testing for "the effect of copper on plant growth" doesn't imply the use of copper filings, as I believe was explained in response to your similar post in February. The same applies to zinc. There is no elemental form of copper or zinc in the soil. Over the eons any that may once have been present has oxidised and reacted with soil acids or carbonic acid and become a copper salt or zinc salt—the metal has become part of a molecule. Your use of various concentrations of copper sulfate solution is still referred to, in abbreviated fashion, as investigating the effect of "the copper concentration" on plant growth.

Are you doing home schooling, that you haven't asked your science teacher about this?

 

[epenguin]

A frequent difference between educational projects and real research, is that in the latter you often do experiments to help tell you how to do the decisive experiment. In the school experiments there is often not time for this, so the results are often not too conclusive.

In case you are not clear enough about what a solution of a salt like copper sulphate really is, it contains just electrically charged ions of copper Cu²⁺ and of the oppositely charged counter ion SO₄^2-. You can't get away from there will always be this counter ion, if it's not SO₄^2- it will be NO₃^- or something else. The Cu²⁺ Will largely be complexed to things in the soil and plant, but that is not relevant to your conclusion.

I don't know quite how you do these experiments, I presume there are defined equal quantities of soil in plastic pots or something so you can so you have a certain definite volume, equal for each of your plants.

I presume you are looking for toxic affects of the copper. Sulphate is quite unlikely to be toxic since after all it is applied liberally and routinely to soils as ammonium sulphate fertiliser. If you want to be rigourous I suggest the best and quite sufficient thing would be to add as well as the copper sulphate, an amount of ammonium sulphate which is 10 or more times the maximum copper sulphate.Then the effects of variation of the sulphate brought with the copper sulphate can be considered negligible.

 

[Nik_2213]

"If you want to be rigorous..."
Also do appropriate controls for the fertiliser, as its modest growth stimulation may affect 'heavy metal' tolerance.

You should be able to find reference to this via mine-site remediation, ecology etc. IIRC, in 'heritage' areas with vegetation at very limit of evolved tolerance, fertilising them 'in usual way' may benefit some species, but hurt others...