Lab: Stream Abrasion
Procedure:
1. Obtain 5 limestone chips and weigh them on a pan balance to the nearest tenth of a gram (one decimal
place)
2. Record the mass on Report Sheet, Table 1, Weathering Time, 0 min. under Mass Remaining (g). Also
fill in % Mass Remaining as 100%.
3. Place chips in plastic jar and fill half way with water. Screw on lid and shake for 2 minutes.
4. Pour out water and pat dry the chips with paper towel.
5. Weigh the shaken chips on the balance are record information on Report Sheet 1. To calculate % Mass
Remaining use the following equation:
% Mass Remaining = (Mass Remaining)/(Mass Remaining at Time 0) X 100
6. Repeat the process two more times shaking for 2 minutes each time. Complete the data table.
7. Before moving onto the next rock type, describe how the shape and the size of the sample changed
during the time of abrasion. Place you observation on Table 4
8. Do the same process for Quartzite. Place data on Table 2.
9. Your instructor will do the Rocks salt and place the results on the board to copy.
10. Transfer your % Mass Remaining after 2 minutes data for each rock type to the Table 3.
11. Graph you data. Plot the Limestone and Quartzite on the top graph. It will be a line graph.
12. Plot all three rocks on the bottom graph. It will be a bar graph.
13. Answer Questions
Lab: Stream Abrasion
Introduction: Running water wears down the Earth’s surface. At first the sediment that is carried by running water is
usually angular in shape but changes to more rounded as it rolls and bounces along the stream bed. The sharper edges
cause the rate of abrasion of the particles to be high at first. As the sediment becomes rounder, abrasion of the
particles slows down.
Objective: Student will determine three factors that affect the rate of abrasion of sediment in running water.
Vocabulary:
Abrasion ______________________________________________________________________
Weathering ____________________________________________________________________
Sediment ______________________________________________________________________
Erosion________________________________________________________________________
Hardness______________________________________________________________________
Soluble________________________________________________________________________
Questions
1. What effect does increased time of abrasion have on the size of the rock fragments?
________________________________________________________________________
2. Which rock type lost the greatest % of mass? Limestone, Quartzite, Rock Salt (circle one)
a. Which physical property of the rock caused it to lose the least? _________________
3. Which property of rock salt caused it to lose the greatest mass? __________________
4. State the relationship between hardness and abrasion.
________________________________________________________________________
5. How did the shape of the particles change as abrasion occurred? ___________________
a. Do you think the abrasion would be faster or slower if it is angular? (circle one)
b. Explain_______________________________________________________________
6. List the three properties that affect the rate of abrasion:
a. ______________________
b. ______________________
c. ______________________
Report Sheet
Table 1
Quartzite (Hardness 7)
Weathering Time (min)
0
2
4
6
Mass Remaining (g)
% Mass Remaining
Table 2
Limestone (Hardness 3)
Weathering Time (min)
0
2
4
6
Mass Remaining (g)
Table 3
Rock Type
Limestone
Quartzite
Rock Salt
% Mass Remaining 2 min.
Table 4
Rock Type
Limestone
Quartzite
Rock Salt
% Mass Remaining