Regents Earth Science
Topic: Weathering
Time: 117 minutes
Name _________________
Date Started ______________
Due Date __________ Period ___
Lab: Rock Breakage and Surface Area
Objective: To investigate the relationship between rock breakage into pieces
and the associated change in surface area, keeping the total volume
constant.
Background: Natural mechanical weathering processes such as temperature
changes, H2O expansion and the splitting of rock by plant roots are
common agents that break rock into smaller pieces. Soil is the result,
in part, of this natural mechanical weathering process. When rock is
broken, new surfaces are exposed to the agents of mechanical
weathering.
During this lab you will use wood blocks to model the rock breakage
and the associated change in surface area of a rock in nature. NOTE:
The total volume of all the pieces remains the same, as we break the
rock into pieces.
Materials:
8 wooden blocks (rock block model)
Metric Ruler
Calculator
Equations: Volume (cm3) = Length x Width x Height
Surface Area (cm2) = Length x Width
Calculated answers to the nearest whole cm. (ex. 35cm3)
Use Centimeters for dimensions (ex. Rock surface area 12cm2)
ES Rock Breakage and Surface Area Lab 12.2013
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Procedure: (hint: place a check mark next to the procedure number as you
complete each procedure step)
1. Gather all materials.
2. Arrange your working area so you will have room for arranging and
measuring the rock block model.
3. Take one of the 8 blocks and measure to the nearest whole centimeter
the length, width and height. The length is usually the longest
dimension. Record values on Table 1: titled: Values for rock block.
Include units for each number.
4. Calculate and record the volume (cm3) of one block. Show the E.S.A. in
Table 1. Have your answer to the nearest whole cm3.
5. Calculate and record the total volume of all of the blocks together in
Table 1 and Table 2. Show the E.S.A. in Table 1. Use the Top view
breakage diagrams for a guide.
6. Calculate and record the total surface area of all 8 blocks together (1
piece) in Table 2. Use the dimensions from Step 3 to do the calculations.
No E.S.A. is necessary. Use the Top view diagrams to aid in how to
arrange your model rock into pieces. Include all six sides.
7. Calculate and record the surface area of 2 pieces, 4 pieces and 8 pieces
on Table 2. No E.S.A’s are necessary. Use the Top View Breakage
diagram for help.
8. Calculate and record the increase in surface area from one piece to two
pieces on Table 2 by subtracting. No E.S.A necessary. Continue filling out
the rest of the increase in surface area values for Table 2.
9. Construct a graph using the graph paper provided. The graph will show
the relationship between the number of pieces of a rock to the surface
area. You will be plotting 4 coordinate points on the graph (example of
one coordinate: 1 piece, 302 cm2).
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The number of pieces is on the X-axis: horizontal axis, also known as the
Independent Variable. The Independent Variable is usually known ahead
of time. The surface area is on the Y-Axis also known as the vertical axis
or the Dependent Variable. The Y-Axis usually is composed of values
that you measured or calculated. This graph needs to have: an
appropriate title (the title describes both x and y axes), labeled axes and
scales. Design the scale so the plotted line takes up most of the graph.
Attach your graph to this lab, when completed.
Example: If the minimum value of area is 320 cm2 and the maximum
value is 671 cm2 the scale should extend from 300 cm2 to 700 cm2. You
do not start at zero unless your lowest value is near zero on any scale.
10.Answer the Conclusion Questions.
Table 1: Values for the rock
block
Dimensions
Value
Length
Width
Height
Volume of one
single block
Total volume of all
blocks together
(1 piece)
E.S.A. for volume of one
single block.
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E.S.A. for total volume of
all blocks together.
Number of pieces
Table 2: Surface Area and Volume Data
Total volume of all Surface Area (cm2)
blocks together
(cm3)
Increase in Area
(cm2)
1
2
4
8
Top view breakage diagram patterns
1 piece
2 pieces
4
4 pieces
8 pieces
Conclusion Questions:
1. Describe the relationship between the numbers of pieces versus the
surface area (keeping the total volume constant). Include data from the lab
to support your answer. _________________________________________
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2. The model blocks that were used in this lab are rectangular in shape. The
length, width and height are not equal. These blocks could be looked upon
as being shaped in “flat plates”. If we used cubes (all dimensions equal), the
shapes could be considered to be cubic.
Compare the weathering rate of a rock that breaks into plates, to a rock
that breaks into cubes. Include your reasoning.
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