Science Buddies: "Ask an Expert"

I am doing a project on the effects of acid rain on roofing materials. I've got everything set except for how to measure the effects. My initial thought was to measure the difference in weight but I'm not sure that will work. Any thoughts? I need to start it in the next couple of days so im looking for a fast response. Thanks in advance.

Hi,

You didn't say what roofing materials you are testing. Asphalt shingles are pretty resistant to everything and I don't know what you could measure after just a few days exposure that would show any difference. Galvanized metal roofing might show some etching or pitting if you used strong enough acid. Concrete tiles would be eroded by acid unless they are sealed. Same with slate tiles. Wooden shingles might show some discoloration.

Take pictures of your materials before and at various times after acid 'rain' treatment. Also, put the materials in the sun outside to simulate actual conditions. There are some newer materials such as resin composites and sealed clays that are supposed to be especially acid-resistant, so if you could get some of those to test, you could show that they are better than conventional roofing materials.

If you have more questions, please describe what you are doing in more detail so we can know how to answer you and post to this thread.

Good luck!

Sybee

Hi there,

What an interesting project idea! Sybee has already given you some great advice. One way to speed up your project would be to include an extremely low pH - one that is much more acidic than actual acid rain. You could argue that the higher acidity could simulate the effects that might happen with time (even at a higher pH). I like your idea of weighing, and Sybee had good suggestions for taking pictures and getting qualitative (descriptive) data, because you won't necessarily know what to look for until you see what happens!

Good luck, and please post again (in this same thread) if you have more questions.

Heather