Take Home Lab 1st Nine Weeks
Scientist:_____________________
Teacher:______________________
Due Date:_____________________
How Do Chemicals Weather Rocks?
Background Information
You have noticed that the concrete alligator statue of the school
mascot “Big Al” is weathering. You think it is because the custodians are cleaning it
with an acid solution. You know that limestone, marble, and other carbonate rocks react
with acid to form carbon dioxide and soluble salts. Rainwater is often acid and can
erode limestone easily. Acid groundwater dissolves limestone underground, forming
caves and sinkholes.
Problem: You want to to prove to the cleaning crew that they should not use acids to
clean “Big Al.”
Hypothesis: If a concrete rock is placed in vinegar, it will weather more because
vinegar is an acid.
Materials
2 equal sized pieces of limestone (concrete) or marble (the rock, not the glass toys)
2 equal sized jars or plastic containers with lids
¼ cup water
¼ cup vinegar
Centimeter ruler
Steps
1. Place an equal number of limestone (concrete) or marble (the stone, not the round
toy) chips in each of two jars.
2. Label the jars "water" and "vinegar".
3. Cover the stones in one jar with ¼ cup water and those in the other with 1/4 cup
vinegar; then screw lids on the jars.
4. Allow the jars to stand for several days. Record your observations each day.
5. Take the remaining stones out of the liquid. Remove the lids from the jars and allow
the water in the bowls to evaporate completely recording the height of the liquid each
day.
6. Compare the amount of solid material remaining in the two bowls.
Controls(the steps and materials that stayed the same for both groups): ____________
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Variable (the one thing that is different between the two groups):
______________________________________________________________________
Observations/Data
Record your observations of the rocks while in the liquid here
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Record your measurement of the height of the liquid while evaporating each day here.
You may add a separate sheet if needed.
Day
1
2
3
Vinegar
Water
On a separate sheet, make a graph showing the above data:
Record your observations of the solid material left in each jar here.
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Conclusion: The hypothesis __________ correct, because______________________
_____________________________________________________________________.
Extension: You can research Texas caves and sinkholes on the internet. You
could also examine other types of rock to see if they react to vinegar in the
same way as carbonate rocks.