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ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
MECHANICAL WEATHERING
Station 1/2 Prediction: _____________________________________________________________
________________________________________________________________________________
Data Table 1 Weathering of Different Size Marble Chips
Weathering time
Mass of marble chips (g)
Observations:
(min.)
Large
small
Size, shape, water color
0
3
6
9
12
15
(Line) Graph 1
Mass of Large and Small Marble Chips vs. Time
20.0
Mass of Chips (g)
19.5
19.0
18.5
18.0
17.5
17.0
0
3
6
9
12
15
Time (min.)
Part 1 Questions
1. What is the effect of TIME on the rate of weathering?
2. What was the PERCENT change in mass of the LARGE marble chips compared to the SMALL chips?
Loss in mass x 100
Original mass
loss in mass x 100
original mass
3. How does the amount of surface area exposed contribute to weathering (pg. 262)
4. What do you think would happen if you continued shaking the marble chips for 24 hours or longer?
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
Station 3/4 Prediction:_____________________________________________________________
________________________________________________________________________________
Data Table 2
Change in Mass of Rocks with Different Composition/Hardness
Hardness on
Initial
Final
Mohs scale
Mass (g)
Mass (g)
Observations
Rock Type
Sandstone
Halite
(rock salt)
(Bar) Graph 2
Change in Mass vs. Rock Type
25 g
20 g
15 g
10 g
5g
0g
Initial
Final
Sandstone Rock
Initial
Final
Halite
Part 2 Questions
1. How did the change in mass of the sandstone compare to the change in mass of the halite?
2. Sandstone is composed of the mineral quartz, use the table on page 701 in your text to find the
hardness of the two minerals
3. Explain the relationship between the hardness and the amount of abrasion, as observed in the
activity?
4. What conclusions can you draw between the results obtained in this activity and the natural process of
weathering that takes place in nature?
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
CHEMICAL WEATHERING
Station 5/6 Prediction: _____________________________________________________________
________________________________________________________________________________
Data Table 3 Chemical Weathering of Rocks with Different Composition
Time
Observations / Descriptions
Limestone
Granite
Chalk
Composition
At the start
15 minutes later
Part 3 Questions
1. What changes did you observe in each sample?
2. What evidence(s) did you observe to support the idea that a chemical change occurred?
3. How is the composition of granite (page 118) different from the minerals in limestone or chalk
(page 107)?
4. How does a weak acid effect rocks in nature?
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
Station 7/8 Prediction: _____________________________________________________________
________________________________________________________________________________
````````
Data Table 4
3
Chemical Weathering of Pyrite and Granite
Time
Observations
Pyrite Chips
Water/Acid Solution
Granite Chips
Water/acid Solution
Start
Days later
Days later
Part 4 Questions (use pg. 261 in text)
1. What changes did you observe that would indicate that chemical weathering took place?
What is the chemical formula for pyrite? What substance in pyrite caused the chemical change?
2.
Label the substances and BALANCE the chemical equation for the oxidation of iron:
Fe
_______
3.
+
O2
________
Fe2O3
____________
Label the substances in the chemical equation for forming carbonic acid (acid rain)
H2 O
___________
+
CO2
_____________
H2CO3
______________
4. How does HYDROLYSIS contribute to the chemical weathering of rocks? (pg 260)
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
While participating in the class post-lab discussion on the results of the weathering lab, complete the analysis
questions below:
1. What is the effect of time on the rate of weathering?
2. How did the mass of the rocks/minerals change over time? Give an example using the rocks.
3. Based on the results from STATION 1/2, how did different particle size of rocks affect the
weathering?
4. From STATION 3/4, explain the relationship between hardness of the minerals in the rock
and the amount of abrasion that occurs. Give an example using two rocks with different
hardness.
5. Which of the different rock/mineral samples had the largest change of mass? The least?
Use the composition of the minerals to explain.
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
6. Describe what would happen if you continued to shake/weather the rocks in water
for 24 hours or longer
7. Which rock/mineral was weathered by the weak acid (rain)? What is it composed of?
Why is granite resistant to chemical weathering in acid?
8. What evidence did you observe to support the idea that a chemical change occurred when
rocks like are exposed to acid (rain)?
9. Explain how hydrolysis contributes to the chemical weathering of rocks.
10. What is the difference between mechanical weathering and chemical weathering?
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
Chemical weathering
weathering
Mass of chips (g)
time
Amount of calcite
Degree of abrasion
Rounding of fragments
Hardness on Mohs scale
Time in river/stream
Chemical weathering
Particle size
weathering
Amount of quartz in the rock
ESS Unit 8 Weathering Lab Names ___________________________________________ Period ________
1. What is the major type of
weathering in Washington D.C.
where AYT is 23°C and AYP is 104
cm?
2. If AYT in D.C. dropped 26°C but
the AYP stayed the same, what
kind of weathering would
dominant?
3. Phoenix, AZ. Has an AYT of 20°C
and an AYP of 20 cm.
How would the climate in
Phoenix have to change for
moderate chemical weathering
to become dominant?
4. According to the graph, no frost action occurs at a AYT above 13°C. Why?
5. In general, how does a climate with strong chemical weathering differ from a climate
with strong mechanical weathering?