Does it Rot or Not? Using Archaeology to Explore Decomposition
By Amy Margaris and Sara Chavarria
OBJECTIVES:
Students will be able to differentiate between materials that will decompose and those that will not, by
learning from modern and archaeological examples. They will learn to use the concepts of organic versus
inorganic to explain why materials do or do not decompose with time. Different rates of composition can
be explored by discussing bones and shells, which are organic but decompose very slowly. This exercise
can be used to complement classroom projects about decomposition, recycling, the life cycle, or the food
chain.
STANDARDS:
3SC-F1: Identify occupations that require the application of science and technology.
4SC-F7: Explain the interaction of living and non-living components within ecosystems.
1SS-E2: Describe the legacy and cultures of prehistoric American Indians in Arizona, including the impact
of, and adaptations to geography.
BACKGROUND INFORMATION:
Archaeologists study how people lived in the past by analyzing the various traces they left behind. The
question of what materials preserve in the archaeological record is a crucial one to archaeologists. While
we’d like to study every possible trace of past human activities, many types of artifacts are rarely
discovered because they do not survive the test of time. As a rule of thumb, artifacts made from “organic”
materials tend to decompose with time, while those made from “inorganic” materials preserve well, and
make up most of what archaeologists generally find when they excavate. We use “organic” to refer to
items that are made from things that were once living. Organic items include wood products, plant fibers,
grain and other food remnants, cloth and textiles, basketry, animal hide, and sinew. Inorganic items are
made from things that were never living, such as clay, brick, plastic, metal, and glass.
Bones and shells form a special category because they come from living beings, and in that sense are
organic. Part of their composition is mineral, however, which makes them very hard and resistant to decay.
They do decompose with time, but much more slowly than do other organic materials.
Because not all artifacts preserve equally well, archaeologists must fill in a lot of gaps when they try to
reconstruct the ways people lived in the past. In some cases, evidence of entire activities may be lost. The
archaeological record is more of a cracked mirror than a perfect reflection of the past. This means there is
lots to be left to the imagination, but also lots of room for future research and learning!
PREP TIME:
Day Before:
photocopy handouts
make overheads
print word bank key and artifact collage key for teacher reference
divide poster board into 2 columns labeled “Organic Materials” and “Inorganic
Materials”
Optional: make Modern Matter illustrations into a set of 8 laminated cards
TIME LINE:
Procedure: 1+ hours
Application: 1 hour
Assessment: 1 hour
TOTAL TIME: 3+ hours
MATERIALS NEEDED:
1. Handout 1: Modern Matter p. 1
2. Overhead 1 OR Modern Matter Cards 1-4
3. Handout 2: Modern Matter p. 2
4. Overhead 2 OR Modern Matter Cards 5-8
5. Overhead 3: The Jacket
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6. Handout 3: Artifact Collage Exercise
7. Handout 4: Text to Artifact Collage Exercise
8. Handout 5: Amy the Archaeologist Assessment
9. Word bank key
10. Artifact collage key
11. Poster board for word bank
12. Crayons to color handouts
13. Optional: Overheads of real archaeological artifacts
VOCABULARY:
decompose
decomposition
tool
material
organic
archaeology
inorganic
archaeologist
mineral
artifact
ACTIVITY:
Setting the Stage
Introduce or review the topic of decomposition. To decompose = to rot. All living things (plants and
animals) are organic, which means they are alive, grow and die. Eventually, all organic materials
decompose because they are eaten by tiny organisms living in the ground, by animals, or even by humans
as food. In the meanwhile, humans can make many useful tools out of organic products. Many other
tools people use are made from things that were never alive, and do not change much through time.
Things that were never alive are called inorganic, or not organic. Inorganic materials do not decompose.
Today you will learn about what is organic and inorganic in our world by thinking like an archaeologist.
Introduce the subject of archaeology and the role of archaeologists: e.g., Archaeologists are scientists
who learn about people who lived a long time ago by studying the objects (artifacts) they left behind.
Procedure: Modern Matter: Does it Rot or Not?
PART I
1. Give each student a copy of Handout 1 and display the matching overhead (Overhead 1).
2. Go over each image with the students, helping them to movie from object to material, and decide if
materials are organic or inorganic.
3. As you go, write each material (food, bone, clay, plastic, paper) on the poster board under “Organic
Materials” or “Inorganic Materials” to make a word bank. This will be useful to students during the
subsequent exercises. (See the provided key.)
4. Give students the second page of the exercise, Handout 2, and display the matching overhead
(Overhead 2). Have each students fill in their own sheet this time, consulting their neighbor if they
need help.
5. When the students have finished, go over the handout and add the new set of materials (metal, glass,
wood, stone) to the word bank poster.
6. OPTIONAL: Some students may argue that bones like the chicken leg are inorganic because they can
be found even when the rest of an animal has rotted away (as they may have seen in cartoons, horror
movies, or during a walk in the woods). If desired, the teacher can present a brief discussion here about
different rates of decomposition, which explains this phenomenon.
Time-Out Discussion: The Mystery of the Bones
All bones come from something was once alive. Remember, they are inside of us right now! Even when
animals die, their bones can stay around for a long time. The same is true of seashells, which are like bones
on the outside, of an animal rather than the inside.
Animals make bones and shells to protect their soft bodies from getting hurt. Bones and shells are very
hard, like armor. When animals die, they begin to decompose. They are eaten by other animals, or by tiny
organisms in the ground that are too small for us to see with just our eyes. These tiny organisms eat bones
and shells, but it takes a very long time because they are so hard. That is why bones and shells often stay in
the ground for so long, where archaeologists can find them.
Question: Do bones and shells rot? Answer: Yes they do – it just takes hundreds of years!
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PART II
6. Display Jacket overhead (Overhead 3) and fill in the blanks with the help of the class.
7. Ask the class to have a look at their own clothes. Have them raise their hand and offer what parts
are organic (cloth, leather, thread, etc.) and what parts are inorganic (metal zipper, plastic button,
etc.). Are they wearing any materials that haven’t been mentioned so far? If so, help the students
figure out what they are made from, so they can determine if the materials are organic or not. Add
these materials to the word bank poster.
Application: Old Artifacts: Do They Rot or Not?
Archaeologists look for artifacts in the ground to learn about the people who left them there long ago.
Artifacts help archaeologists learn about what people ate, what they wore, and how they lived. You are
now experts in decomposition, and an archaeologist needs your help!
We will be looking at pictures of some tools that were left behind by people hundreds of years ago. We
must decide which parts of the tools archaeologists will probably find because they are inorganic, and
do not decompose. Which parts are organic, and will probably decompose?
2. Pass out Handouts 3 & 4 (Artifact Collage and the accompanying text).
3. Work as a class. Have students take turns reading the items on the sheet aloud, while the class circles
the appropriate parts of the pictures. (See the provided key.) Students can use the word bank poster
to help them decide which materials are inorganic.
Optional: The teacher can display images of real artifacts on the overhead projector during the exercise.
Optional: The teacher can make a second copy of the Artifact Collage sheet. After finishing the first sheet,
students can repeat the exercise but circling what WILL rot. (What archaeologists WILL NOT find in
500 years.)
4.
5.
Have students give an appropriate title to their collage sheet, such as: “These Things Do Not Rot
Because They Are Not Organic”.
Students can spend time coloring their sheets.
Assessment
Meet Amy the Archaeologist! Amy has gotten permission to look for artifacts, and has brought along her
tools to help her dig up the artifacts and carefully study them. What has she brought that will someday
rot, and what will not rot?
1. Have students fill in the sheet on their own, using what they have learned in the previous exercises.
[10 questions]
Optional: Allow students to consult the word bank poster for help.
2. Students can color in the sheet if they have extra time.
Closure
Suggestions are welcome!
ADDITIONAL RESOURCES:
http://www.astc.org/exhibitions/rotten/rot.htm (more about how things rot)
http://www.findarticles.com/cf_dls/m1590/13_57/73537927/p1/article.jhtml (decomposition activity)
http://www.offwell.free-online.co.uk/decompos.htm (Photographs capture the decomposition of an
animal carcass. This one is graphic.)
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NAME _____________________________ DATE _______________________
1. People long ago knew how to sew and make their own
clothes. They used a needle and thread to sew leather and
cloth. Needles were made of bone, and not metal.
Circle what an archaeologist would find in 500 years.
(HINT: What would NOT rot?)
2. People long ago used spears for hunting. The stone spear
point was sharp to kill animals for food. The wood handle
was very long to help throw the spear a long way.
Circle what an archaeologist would find in 500 years.
3. People long ago used clay pots to hold food and to cook.
This pot is used to hold beans.
Circle what an archaeologist would find in 500 years.
4. People long ago did not have grocery stores where they
could buy food. They used grinding stones to make their
own flour from corn kernels. The little stone was rubbed
against the big stone to grind corn into flour.
Circle what an archaeologist would find in 500 years.
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ARTIFACT COLLAGE ANSWER KEY
1. People long ago knew how to sew and make their own
clothes. They used a needle and thread to sew leather and
cloth. Needles were made of bone, and not metal.
Circle what an archaeologist would find in 500 years.
(HINT: What would NOT rot?)
Answer: nothing
4. People long ago used spears for hunting. The stone spear
point was sharp to kill animals for food. The wood handle
was very long to help throw the spear a long way.
Circle what an archaeologist would find in 500 years.
Answer: the stone spear point
5. People long ago used clay pots to hold food and to cook.
This pot is used to hold beans.
Circle what an archaeologist would find in 500 years.
Answer: the clay pot
4. People long ago did not have grocery stores where they
could buy food. They used grinding stones to make their
own flour from corn kernels. The little stone was rubbed
against the big stone to grind corn into flour.
Circle what an archaeologist would find in 500 years.
Answer: the two grinding stones
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WORD BANK KEY
Organic
Materials
Examples
Inorganic
Materials
Examples
food
chicken/meat, beans, corn
clay
brick, pot
paper
book
plastic
beach bucket
wood
tree, spear shaft
metal
can, gold
cloth
jacket, leather
stone
castle, spear,
grinding stones
bone
chicken leg, needle
glass
window
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