zoe-the effects of acid on metal

My project question was what are the effects of acid on metal. Today is 1 week after i have started my project. The entire project will take two weeks. I have been checking on my project every day and recording my observations. On the first day, I put three of each type of nail(brass, iron, and stainless steel)in 3 cups each. The first row of cups is filled with nothing but air. This is group A. The second row of cups is filled with tap water(to represent average rainwater becuase they have a close pH value), and distilled white vinegar(because it has a close pH value to acid rain). I have had some very intiresting results so far. As time has progressed, each different group of nails put into either water, air, or vinegar, has had different results. I will share the results I just got today, on the 7th day of my experiment.

AIR
(all unchanged)

VINEGAR
Brass- On the 3rd day, the water took on a bluish color and day by day the color has gotten darker and more prominent. However, the nails remain unchanged
Iron- On the 2nd day, a red line formed around the edge of the vinegar at the top. Over time, the line has gotten darker and more red. The nails, which when I bought them were a metallic color got to be completely black by the 4th day. There are also many black flakes that have fallen off the nail and have gathered at the bottom.
Stainless Steel- There is a red line much like that on the iron, but more orange in color. The nails, however, remain unchanged.

WATER
Brass- On the 5th day, some small, white precipitates formed, but they are now gone and the nails look unchanged.
Iron- On the 2nd day, the process of corrosion started, but today, the nails are completly coated in a light orange rust. The water has also taken on this color, because the rust color from the corrosion leached into it. The coat of corrosion looks very thick, almost like a fur coat.
Stainless Steel- On the 3rd day, corrosion patches started to form and today the patches are very big and thick. The color, like with the iron, has leached off into the water. There is now a vein like pattern that is going along the bottom of the cup. The color is more re than with the iron.

(i do have pictures but they would not load onto blogger :[)