Chemical and Mechanical Weathering of Rock Lab: Part 1
Purpose: To understand the chemical and mechanical processes of weathering by doing a series of
hands-on experiments.
Matierals: bean seeds
Calcium sulfate
Halite chips
HCl
Marble chips
Balance
Al dish
forceps
pipet
plastic cups
Tray
stopwatch
water
marker weighing dish
Magnifying glass
Procedures:
Part 1: Mechanical Weathering
a. Obtain 15 g of marble chips. Record the mass in data table and place chips in a sample container.
b. Add water to container until chips are completely covered. Record observation in table.
c. Tighten lid and shake container for 3 minutes. Record observations.
d. Dump the water BUT NOT the marble chips and dry them with a paper towel. Weigh the chips and
record mass in table.
e. Use a magnifying glass, observe condition of chips. Place chips back into container and repeat steps
b-e 3 more times for a total of 12 minutes of shaking. Record all observations in table.
f. Repeat steps a-e for the halite and the granite chips.
g. Clean container with water after testing is done.
Part 2: Chemical Weathering
a. Place three pieces of marble into a small plastic cup and 3 pieces of granite into another plastic cup.
b. Using a pipet, add enough 1M HCl acid to cover the samples in both cups and let the cups sit for 20
minutes.
c. After 20 minutes, observe and record the effects the acid had on the chips in the table.
Part 3: Oxidation
a. Place two pieces of Pyrite into a small plastic cup. Record observations in table.
b. Using a pipet, add enough 1M HCl acid to cover the Pyrite in the cup. Place on the ridge of the lab
benches (along the walls) until next class.
c. Using forceps, remove the Pyrite pieces and place on a paper towel. Using a magnifying glass, record
all observations in data table.
Data Table:
Part 1: Mechanical Weathering
Type of
Material
Original mass
& Observations
Mass after 3 min. &
Observations
Mass after 6
min. &
Observations
Mass after 9
min. &
Observations
Mass after 12
min. &
Observations
Marble
Chips
Halite
Chips
Granite
Chips
Part 2: Chemical Weathering
Time
20
minutes
Marble Observations
Granite Observations
1 Day
Part 3: Oxidation
Initial Observations
Observations after 2 days
Analysis Questions: 1. What was the effect of the amount of time and the amount of weathering in part 1?
2. How did the mass of the marble chips change with the amount of time in part 1? The mass of the
halite? The mass of the granite? 3. Which rock in part 1 is the most resistant to this type of mechanical
weathering? 4. What changes did you see in part 2? 5. Did a chemical change happen? How do you
know? 6. Based on your observations in part 2, what variables affect the rate of chemical weathering on a
rock? 7. Which sample in part 2 is the most resistant to chemical weathering? 8. What type of weathering
happened in part 3? Support your answer with evidence. 9. What changes were seen after 2 days in the
acidic solution in part 3? 10. What caused the changes to the pyrite chips in part 3?
Summary: Explain weathering and the types of weathering that alter the surface of the earth and factors
that speed up or slow down weathering.
Chemical and Mechanical Weathering of Rock Lab: Part 2
Purpose: To understand the chemical and mechanical processes of weathering by doing a series of
hands-on experiments.
Matierals: bean seeds
Calcium sulfate
Al dish
marker
Procedure:
Part 4: Organic Process
a. Use an aluminum (Al) dish. Mark on the bottom your group’s initials.
b. Place 2 spoonfuls of calcium sulfate into the dish and add water until the calcium sulfate forms a thin
paste. Add a little water at a time!
c. Add 10 bean seed to the dish and make sure to submerge them in the paste. The mixture represents
rock.
d. Observe the mixture over the next 2 weeks and record observations in a data table.
Data Table:
Date
Observations
Analysis.1. How did the growing bean seeds affect the simulate rock in this part of the lab? 2. Name two
everyday or common examples of “organic” soil disruption.
Summary: Sum up this portion of the lab and explain how bioactivity adds in the weathering of material at
the Earth’s surface.