Name: ______________________________ Date: _________________ Period: _____
Partner _______________________________
8th Grade Science
Mr. Vorstadt
Erosion and Weathering
Background Information: Weathering is defined as the group of destructive forces that change
the physical and chemical character of rock near the earth’s surface.
 Mechanical or physical weathering is the breaking down of rocks into smaller pieces. The
change in the rock is physical with little or no chemical change.
Examples of mechanical weathering include: frost action, abrasion, and pressure release.
 Chemical weathering is the breakdown of rock from exposure to water and atmospheric
gases (usually carbon dioxide, oxygen, and water vapor). As these agents break the rock,
new chemical compounds form.
Examples of chemical weathering include: rusting, acid breakdown, and solution
weathering.
Materials:
 pieces of Chalk
 Two beakers
 Water
 Vinegar or HCl
 Goggles
 Graduated cylinder
Exploration / Concept Introduction
1- I am going to give each group a piece of chalk and a paper plate. The chalk will be our rock. In a
minute, I want you to weather, or break up, this rock. How will you do it? __________________
_________________________________________________________________________________
2- Break up your chalk.
3- You broke up your chalk and made sediment. So by banging on it you were physically
weathering the rock. Physically weathering involves something physically touching the rock.
4- What are some things in nature that could physically weather rocks? _____________________
_________________________________________________________________________________
5- Can you think of any places where you can see physical weathering of rocks? ______________
_________________________________________________________________________________
6- Now we are going to put water on the rocks and see what happens. What happened? _______
_________________________________________________________________________________
7- Pour the vinegar or HCl on your chalk. What happened? ________________________________
________________________________________________________________________________
Questions:
1. What is the effect of water on the chalk? _____________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
2. What is the effect of vinegar/acid on the chalk? _______________________________________
_________________________________________________________________________________
Wind & Weathering
Background Information: The force of the wind can change the surface of the earth in a small
way by removing materials and wearing down rock surfaces. Rocks that are made of soft
minerals are broken down when they are hit by wind-blown pieces of sand or smaller particles of
rock. This kind of weathering is not very strong. Wind takes a lot of energy to move sand and
rock. Each impact can break off small pieces of the larger rock, leaving them in place. Fragments
of rock left on the larger rock stay in place and wait for stronger forces, such as water, to carry
them away (erosion).
Purpose: To simulate the effects of weathering by wind.
Question: How does the size of rock carried by the wind affect the weathering of a larger rock?
Hypothesis: If _______________________________________________________________,
then ________________________________________________________________________.
Materials:
 2 canisters
 2 sugar cubes
 1 sheet of fine grained sand paper
 1 sheet of coarse grained sandpaper
 Hand lens 1 piece of screen
 balance
Procedure:
1. Line one of the canisters with a strip of coarse sandpaper. Label the canister “coarse.”
2. Line the other canister with a strip of fine sandpaper. Label the canister “fine.”
3. Put a sugar in each canister. Gently swirl the canisters for one minute.
4. After one minute, open the canisters and compare the sugar compare the sugar cubes. Record
your observations in your data table.
5. Repeat step 4 for a total of 5 trials.
Data:
Make a table to record your data for:
1. The effect of the coarse sandpaper on the sugar cube
2. The effect of the fine sandpaper on the sugar cube
Data Analysis: Describe the relationship between the size of the sandpaper and the weathering
of the sugar cube.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
Questions:
1. Which sand paper was most effective in breaking down the sugar cube fastest? Why?
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
2. Where might you see a similar type of weathering in nature? ____________________________
_________________________________________________________________________________
3. Explain why this was an EXPERIMENTAL investigation._________________________________
_________________________________________________________________________________
_________________________________________________________________________________
4. List the
 independent variable:___________________________________________________________
_________________________________________________________________________________
 dependent variable:____________________________________________________________
_________________________________________________________________________________
 controls in this investigation:_____________________________________________________
_________________________________________________________________________________
Conclusion: Write a short paragraph answering the original questions. Use actual data to explain
why your hypothesis was supported or not supported.
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________