Investigating Factors that Influence Weathering of Monuments in a Cemetery

This activity is designed so students can:
characterize chemical and physical weathering as observed in a cemetery.
determine that rocks weather at different rates due to a variety of factors.
develop observational, questioning and investigative skills and techniques.
collect and analyze data and draw conclusions.
review rock identification.
become familiar with the terms weathering, chemical weathering, and physical weathering.

This field investigation is designed to be used by 20 or more 8th grade earth science students. The number of students and chaperones will be determined by the size and terrain of the cemetery used. It will take from 1-3 hours on site to make observations and carry out the resulting investigation. Students should be able to identify the rocks that are likely to be found in a cemetery before doing this investigation and will require no specialized equipment. It is recommended that students participate in a discussion of appropriate cemetery behavior before embarking on the trip. This activity may be adapted for any cemetery that has monuments of various types and ages.

Gather with your students near the cemetery entrance and review cemetery behavior. Introduce them to the cemetery by providing them with a brief history. "The Stone Church congregation was established in 1855. The cemetery property was added in 1863. The church is located in both Houston and Sheldon townships, the township line runs down the center of the church. The church and cemetery are both still in use today." Help them "get comfortable" with their surroundings.

1. Divide students into teams. Ask them to make and record 10 detailed observations about the monuments. This should take anywhere from 10 to 20 minutes. If they need prodding, hint at the different types of rocks and the condition of the monuments. Spread them out around the cemetery.
2. Regroup at a logical place when most students appear to be done. List and discuss their observations and any questions that were generated. Develop the vocabulary necessary to describe their observations. Terms to include: weathering (chemical and physical or mechanical) as different than erosion.
3. If questions were not generated, guide the students in developing some investigable ones. (Suggestions are given below.)
4. Select a question or questions to pursue. Have students meet with their group and decide what needs to be measured or tested.
5. Within the group, students need to write down the procedure they will use and collect their data. Any modifications of their procedure should be noted. Help the groups decide if they can collect all the data they need or if data will need to be shared. (If you want to look at overall trends or have joined up with a social studies or math teacher, you may want to divide the cemetery up between all of your students, collect data and share the pieces each group will need.)
6. Analysis of data can be done at the cemetery or back at school.
7. Students need to generate a conclusion and perhaps a hypothesis before presenting their findings to the entire class. Student Lab Sheet (Acrobat (PDF) 26kB Aug22 07) Photos of typical cemetery (Acrobat (PDF) 1.2MB Aug22 07)

The small community of Houston, MN has seven cemeteries within a short bus ride from the school. All of them have monuments that date from the mid 1800s to the present. Monuments of marble, limestone, granite, gabbro and other miscellaneous sedimentary, igneous and metamorphic rock can be found with varying amounts of weathering.

Students should be able to distinguish the granite, gabbro, and other igneous rocks from one another. Marble and limestone will be a little harder to tell apart. Look for typical metamorphic features and more distinct "baked looking" crystal-like structure in the marble. Materials needed include measuring tools (meter stick or tape and perhaps a length of tape), formulas for calculating area and volume and a compass or map for determining direction. Students should not be allowed acid bottles.

Students observations/data may include (but should not be limited too):
direction the monument is facing (may be the same for most or large parts of the cemetery)
type of stone
dimensions of the monument or its face
whether the monument is polished or rough
date of placement (opportunity for discussion of assumptions, we assume the monument was placed at the time of death)
placement of the monument (horizontal or vertical)
location with respect to vegetation
amount of vegetation on it
legibility of the inscription (determine a numerical scale from 1 to 5, from very legible to can't read most of it) - be sure to check all sides of the monument

Depending on the size of the school and the location of the cemetery, you may need to deal with grave sites of family, friends or fellow students. Be prepared.

Some possible questions for investigation are:
Will monuments of marble/limestone weather faster than those of granite?
Will igneous or metamorphic monuments weather more slowly than those of sedimentary rocks?
Do monuments placed near trees or shrubs weather faster than those in the open?
Is it possible that the direction the monument is facing matters, and monuments placed into the prevailing winds will weather faster than others?
Could the increase in acid rain make newer monuments weather disproportionately faster than older monuments have weathered?
Will horizontally placed monuments weather faster than vertically placed monuments?
Will the monuments with the most surface area weather faster than those of smaller surface areas?
Do monuments placed in acidic soil (near pine trees) weather faster than monuments that are not in acidic soil (near deciduous trees or no trees).
Will monuments made of locally quarried stone weather slower than monuments made of imported stone?
Does the side of the monument facing the afternoon sun weather faster then the opposite face?

Student data will vary with the question asked and the cemetery. Make sure to help with variable control where needed. Encourage students to report their data with some type of graph if at all possible. You may wish to visit a monument or memorial operation to obtain some polished and rough cut rock samples. After students present their results to the class a list of factors influencing weathering should be generated (add any that were missed).

This activity is different from other weathering activities because the students discover several factors that influence weathering from their own observations. They ask the questions and design the investigation. It also uses a real life setting rather than a lab setting. The vocabulary and scientific thinking processes sneak in.

A quick Internet search using the phrase "cemetery geology" will turn up a few similar ideas. One site to check out is: http://www.geol.lsu.edu/Faculty/Ferrell/class/Graveyard/graveyard.html

This article just appeared in the LaCrosse Tribune and might be interesting for students to read as they finish this activity. If a great deal of restoration has taken place in your cemetery, this activity would have to be modified.

Assessment may be formally or informally done from students' written record or the resulting oral report. Journals may be collected or a formal worksheet may be used (sample included). It will be obvious in the field which students are on task or not.

8. III.A.2 - The student will describe how features on the Earth's surface are created and constantly changing through a combination of slow and rapid processes of weathering....