First of all, you want to identify the constituents of acid rain so that you can prepare a synthetic solution of it. What acids (sulfuric acid, nitric acid, etc.) will be in the water and what pH will the water be? You can research which acids and pH values are most common in acid rainfall to help you with this. Then you have to decide which type(s) of soil you would like to test. Do you want to test the filtration of various types of soil or just one type?

You could probably set up your soil in a planting pot with rocks below the soil so that the water you pour on the soil will run off below the soil and settle with the rocks at the bottom. You can then remove the soil and pour the run off water out to measure the pH. This is just one possible experimental set-up, but it really depends on the questions you want to ask.

For example, do you want to know whether the soil causes the water to become more/less acidic? Would you like to test the effects over time (maybe a few days)? One interesting thing you could do would be to plant some seeds in maybe 5 different pots of soil (the same soil) and see if acid rain has a negative effect on the ability of the seeds to mature and grow into a plant. Of course, one of your pots would be your control where you would just use regular water. There are a lot of interesting questions you could ask. If you need more assistance I will be glad to help. Good luck!

I'm a geologist, but I don't really know much about soil.I do know that the ability of soil to neutralize acid (such as from acid rain) is highly dependent on its calcite content. I believe this is called the "buffering capacity" of the soil.

Calcite is the mineral (CaCO₃) that limestone is made of. Therefore, soils that are formed from the decomposition of limestone tend to have fairly high pH (maybe even >7). They are "basic", rather than acidic and can withstand a lot more acid rain before their pH changes very much. Soils that start out acidic (pH <7) are much more quickly effected by acid rain and may become inhospitable to the plant/animal life that once lived in them.

Also, the water that falls as acid rain that passes through a soil with "low buffering capacity" will still be acidic when it enters the streams and rivers and can cause fish and other animal populations to decline. You can find out more about the people at UCSB who actually study soil at:

UCSB Geology site.