Re: What kind of effect does acid rain have on quartz?

Hi Charles, thanks for asking us!

To answer your first question about acid rain, the answer is "not much."

Quartz is a pretty durable mineral, SiO2.  You have probably seen a quartz 
crystal and are familiar with the hexagonal shape of a well-formed one.  
Rocks can have pieces of quartz in their regular structures that look 
nothing like the crystals, but are still very much quartz.  Granite is one 
of the better places to find quartz in a rock-- If you can find someone to 
show you a building near home or a tombstone in a graveyard that's made of 
granite, it'll give you a good idea of what happens to quartz (usually the 
clear or white dots in the granite) in acid rain.  And as I mentioned 
earlier, not much happens to quartz.  In your area, buildings and statues 
that have been damaged by acid rain are usually made of limestone or 
marble.   

Now for the experiment. I wonder if you are indeed growing Quartz crystals, 
since in nature, it happens at incredibly high temperatures.  But I'm sure 
it could happen.  If you're NOT growing quartz crystals, I'm not sure I can 
help (but hey, you can always write back if you need to!).  But you're on 
the right track by growing Two sets of crystals, one with the acid, and one 
without.  The one without is called your control.  

Anyway, since I don't know exactly what you're using, I'll use salt 
(NaCl)as an example for how crystals grow.  Regular table salt, if you look 
at it under a magnifying lens, has crystals that are almost perfect cubes. 
 In water, salt will dissolve and reform when the water cools or 
evaporates, and will again be a crystal that looks just the same.  Halite 
is the mineral name for rock salt, and can grow to be pretty big, but hit 
it with a hammer, or dissolve it in water and it'll end up as always, 
cubical in shape.  The reason for this is that in breaking or dissolving 
salt, it doesn't change in its chemical composition- it's still salt, still 
tastes salty.  If you drop some lemon juice on a pile of salt, it doesn't 
do much- there's no chemical reaction, like with quartz.  When it 
dissolves, the individual salt molecules loosen their grip on each other 
and float around in the salt water solution, and when the water in between 
the molecules gets to be less and less and the salt molecules get closer 
and closer, they rearrange like puzzle pieces back into the shapes they 
were originally in. So a sat crystal would look like a big repeating block 
of   NaClNaClNaClNaCl     
     ClNaClNaClNaClNa  over and over and over....

But drop something acidic on limestone, a scratched seashell, marble, or 
baking soda, and it'll start fizzing.  This is because the atoms in both 
the the acid and whatever you're putting it on are rearranging themselves 
and trading electrons.  After a while, the fizzing stops- this is because 
the acid and the base that you put it on have finished the reaction, and 
the chemicals are considered neutral.  This is what's happened to the 
limestone in the old statues and gravestones.  

So here's what to do for your experiment:
1. Find out the name of the crystal you will be growing and record it- 
write it on the label of the beaker you're growing the crystals in.

2. Get close to your crystals- find a magnifying lens and make drawings of 
the crystals you're using BEFORE you run the experiment.

3. If you have enough extra crystals that you're starting out with, drop a 
little lemon juice and observe (and record!!) what you see and hear and 
feel happening.

4. Make your hypothesis and write it down.

5. Run the experiment and see what happens!   

6. Record what ends up happening and start wondering why or why not and how 
you can make something different happen and where else you think it might 
happen (in buildings or lakes or bathtubs..who knows!?)

Best of luck to you in your experiments!!   --Sarah