Editing Ocean Acidification (section)

== Demonstration ==

;Preparation:
* Prepare the NaOH solution: for every liter of water, dissolve 40g of NaOH. Once dissolved, store and label the solution.
* Prepare the CaCl solution: for every liter of water, dissolve 27.75g of CaCl<sub>2</sub>. Once dissolved, store and label the solution.

;Presentation:
# Set up the beakers: Fill each beaker with 500mL of water. In one beaker, drop in a few pieces of chalk (crushed) or limestone, as well as a piece of dry ice. In the other beaker, mix in 100mL of the 0.25 CaCl solution.
# When students come up, show them the beaker with the chalk/limestone in it. Ask them to look at the chalk/limestone and look for evidence of it breaking down. If they see it, ask them to think of possible causes for it.
# Show them a separate piece of chalk/limestone, and use the eyedropper to put 1-2 drops of vinegar on it. The chalk/limestone will start to fizz! Ask the students for ideas on the connection between the vinegar and the beaker, being sure to note that there is no vinegar in the beaker. What else could be causing it?
# Now show the beaker with the dissolved CaCl. Add 250mL of carbonated water to the beaker (filling it to the 850mL mark), and use an eyedropper to slowly add the NaOH solution to the beaker. After several drops, small particles will start to appear in the solution!
#* Once the second solution gets too milky from precipitation, you'll need to rinse it out and remake the solution. Both solutions can safely go down drains.