Science Buddies: "Ask an Expert"

I am planning my science fair project. My question is, "How do different vitamins and minerals affect a plant's (haven't decided what plant yet) growth and health?" I plan on having different plants (preferable a flowering one) and giving them a different vitamin or mineral through their water to see how it affects there growth and health. I want to know why though. I've come up with the idea of measuring the water's pH level. I want to do this to see if it just had no affect on the plant or caused a chemical complication or it just wasn't able to absorb it. If I keep adding it over and over again and that pH level is shown in the water then I would know that it didn't absorb it. Where or what are the pH levels of these. Any tips or alterations for my experiment are welcome. If my idea to find out the amount of vitamin won't work then what could I do to measure it?

Hi! I think considering pH is a good idea. I think you should take a sample of the soil and find it's pH after a predetermined amount of time (you could do a before/after measure which means you would take a sample before the treatment and then one sample at the end of the treatment).

I am a little confused on your last question. Could you clarify that?

I have also found some helpful likes:
Here is a good website that discusses plant nutrients and has a brief discussion on soil pH: http://www.ncagr.gov/cyber/kidswrld/plant/nutrient.htm.

Here is also a link talking about testing your soil pH: http://www.howtogardenadvice.com/soil_p ... sting.html


Thanks,
Jenny

I want to find the pH in order to tell the amount of vitamins left in the soil. I would like any help from anyone on how to do this. If I can't find out the amount of vitamins with the pH method the how could I?
If you think that might be too hard then can you tell me something that could make it more difficult or interesting.

Can I ask if you thought I was doing something else and if so what was it?

Hi Tim,

I think you have a very interesting question! One way to find out if your pH method will work is to put a known amount of vitamin into soil without any plants, and then measure the pH change associated with that amount of vitamin. You should do this for several amounts of vitamin, so you can generate a regression, which you can then use to match any pH you measure to a predicted amount of vitamin in the soil. This is called a standard curve, if you want to look up some information on the process.

Vitamin C (ascorbic acid) would be a good vitamin for you to use, since it is an acid and should alter pH in a predictable way.

You may want to focus on only one or two vitamins, because you'll need to test them independently. It would be too difficult to tell what's going on with each one if you add them both to the same plant. Since it's good to use the highest sample size (number of plants) possible, it will be best to focus on one or two vitamins and make sure you get some results you can interpret.

Let us know if you have more questions!

Heather