Acid RainProject #4
Showing the effects of acid rain.
Acid rain is created when water and sulfur in the air mix together to create sulfuric acid. Sulfuric acid is a moderately strong acid that will dissolve many types of stone. The most commonly seen effect is on buildings and headstones that are made of marble or limestone. Sulfuric acid slowly dissolves marble and limestone and given enough time, it will remove all the details and etch the surface.
To recreate this in a rock tumbler put limestone or marble pieces in the tumbler and add vinegar. To be more realistic to what happens naturally, don’t add water or rock tumbling grit.
Run the tumbler and check every 24 hours or so. The lid may pop off because of the carbonic gas that builds up in the barrel. This is CO2 and it is released as the acid dissolves marbles and limestone in nature too.
Within a couple of days or so you should be able to see the effect of the acid on the limestone as the corners are all rounded and the rocks become more smooth.
Mining For MineralsProject #5
Finding minerals in the ground is not easy. Mining engineers and geologists spend a lot of time looking for mineral deposits and then trying to figure out what that deposit looks like underground. Mineral deposits are never a uniform shape or size. They can be big blobs or long thin veins.
To understand this mix up a batch of your favorite chocolate chip cookie dough. Because you don’t know where the chocolate chips are in the dough you can use a straw to push through the dough. When you pull out the straw you will see a “core sample” of the cookie dough. This is just like geologist when they drill a core sample out of the ground.
Now you can examine the core sample to look at how frequent the chocolate chips are.
If you mix a separate batch of dough but don’t mix it up very well then you can see the layers of flour, eggs, oil, and other ingredients.
Copper PenniesProject #6
Copper is a valuable mineral that comes from azurite and malachite, chalcocite, chalcopyrite, and many other copper minerals.
In 1980 copper prices rose so high that it cost much more than a penny to make a penny. In 1982 the U.S. Mint decided to make penny’s differently. They make the penny’s out of zinc and put a copper coating (called clad) over the zinc so the pennies still looked like a penny.
Gather a collection of pennies from 1982, 1982D, 1983, 1984, & 1985. You will also need a ruler and a piece of card stock 1” x 1”.
Fold the card stock in half and place the ruler over the “V” forming a balance. Start with one penny (1984) on one end and place a different penny on the other end. Use this method to sort out which are heavier/lighter.
Log your findings as you go. Why are some heavier?
You can take the penny’s that are “clad” in copper and put one in a glass of vinegar. In a few days the zinc may dissolve leaving only the shell of copper.