Ph values Please help me answer the below questions.

[coleman]

I am doing a project about ph values and how it changes in soil after adding water.

I need to know what value of ph is neutral?
I need to know what range of ph values is acidic?
I need to know what range of ph values is basic?

[donnahardy2]

Hi Coleman,

pH is measure of the concentration of hydrogen ions in solution. Here is a website that gives more information:

http://www.ph-meter.info/pH-definition

A pH of 7 is considered neutral, and values lower than 7 are acidic and values higher than 7 are basic or alkaline. I don't know if you have studied any chemistry in your science class yet, but you might check out your science book and see if you can find more information on this topic.

Here is a website that includes information on soil pH and the importance of solid pH. You will also find some ideas an experiment.

http://soil.gsfc.nasa.gov/soil_pH/plant_pH.htm

It is difficult to accurately measure the pH of soil because there are usually very few ions present. The best way is to use a pH meter with a special electrode that works in low ionic solutions like water. However, if you don't have access to a pH meter, you can use pH paper strips to test your samples.

The pH of soil is measured by adding pure water, mixing, and letting it sit for a while, and then decanting (separating it from the water) and measuring the pH of the water. Here is a website that gives a typical procedure:

http://www.globe.gov/tctg/soilph.pdf?sectionId=97

Now for your project. This can be an excellent project, but you need to do lots of background reading, and think of a question you can answer by doing an experiment. For example, if you have enough time, since pH affects plant growth, you could measure the pH of your soil and try growing different types of plants. Or, you could collect samples from a variety of locations and measure the pH. You will find out from your background reading that nitrogen affects pH, so you might ask how you would adjust the pH to be optimum for growing radishes or lima beans, or another plant. I'm sure you can think of a question that could be answered by doing a unique experiment. Do plan to include a control in your experiment and try to do the experiment at least twice.

The science buddies website has the best information for thinking about your question and using the scientific method:

https://www.sciencebuddies.org/science- ... shtml[code][/code]

I hope this helps. Let us know if you have more questions.


Donna Hardy

[Ellums]

Donna-Is it possible to edit your post? A little typo concerning pH-you say below 7 is neutral-I'm sure you meant acid...

[donnahardy2]

Hi Coleman,

Ellums is correct. A pH below 7 is acidic as there are more hydrogen ions(H+)present compared to hydroxide ions (OH-)

Donna