CHEMICAL WEATHERING
ON
CHALK
Parents Help Needed!
Objective: This investigation will also help you understand how a form of chemical weathering works in nature. In this experiment, you will observe the connection between particle size and reaction rate.
Problem: How does the size of the rock affect the rate, how fast or slow, of chemical weathering?
Procedure:
1. Carefully pour vinegar into two cups, about 2” deep. CAUTION: Becareful not to spill acid on your clothing or skin. If you do wash it off quickly.
2. Using the scale find the mass of each piece of chalk. Record the masses in the Data Table. They should be about the same.
3. Break one piece of chalk into several small pieces.
4. At the same time place the broken and unbroken piece of chalk into the two cups of vinegar (acid). What happens?
5. Wait 5 minutes. Pour the contents of one cup into a paper strainer. Do the same with the other cup.
6. Gently dry both samples of chalk with paper towels.
7. Find the mass of each sample of chalk. Record the masses in the Data Table. Calculate the amount of chalk that reacted in each cup and fill out the rest of the Data Table.
Observations:
DATA TABLE
MASSES
|
SETUP |
WHOLE PIECE |
BROKEN PIECES |
|
Mass before placed in acid
|
|
|
|
Mass after being placed in acid
|
|
|
|
Amount of chalk that reacted with the acid
|
|
|
Conclusions:
1. In which beaker did the reaction proceed more rapidly?
2. Besides the difference in mass, how else could you tell the one reaction was faster than the other was?
Thinking Questions:
1. What are some pieces of evidence you have seen outside of chemical weathering?
2. What in nature is causing chemical weathering like our vinegar is here in the lab?
3. Check out your rock. What is the evidence that there is weathering? What type of weathering would it be?
HOMEWORK:
Pretend you were given the job of EROSION expert! Your job will be to create a booklet describing the damage done by erosion and weathering in your hometown. Explain what is being done to correct the damage or what you think should be done. This booklet will be used to tell the people in your town how to stop or fix weathering and erosion!