Written In Bone: Buried Lives of Jamestown and Colonial Maryland
By Sally M. Walker
Chapter Four Vocabulary:
Prehistoric
corrode
Iron Pike
copper oxide
Lance like
lipping
Encrusted
dysentery
absolute proof
Essay Questions:
1. Earth’s weathering process will cause graves to be forgotten. Explain how America’s cultural and
religious behaviors impede this natural process.
2. What time period is prehistoric to America?
3. Does every continent have the same prehistoric date? Explain your reasoning.
4. What is the process called when iron turns to rust? Is iron the only metal that oxygen reacts with on
Earth?
5. In what way does knowledge of soil composition aid archaeologists and anthropologists?
6. Brainstorm why shrouding pins would turn soil green? What is this process called?
7. How do anthropologists utilize body systems to determine the lifestyle of a buried person?
8. Why is absolute proof important throughout an excavation? Use a synonym for this phrase during
your explanation.
9. Rationalize why the captain’s burial was outside the “norm” of other burial sites.
Interactive: Conduct the following experiment.
MUST IT RUST?
THE REACTION BETWEEN IRON & OXYGEN
Knight Foundation Summer Institute
Kathleen Heffner, Beeber Middle School
Emily Dorean, Haverford College
Introduction:
Everything in the world is made up
of chemicals, and all chemicals are made up of tiny particles called atoms. A
chemical reaction occurs when atoms join together or break apart to form new
and different combinations of atoms. In this experiment we will be
investigating a chemical reaction between iron and oxygen, which is given by the
formula 4Fe + 3O2= 2Fe2O3. This formula shows
that when iron is found in the presence of oxygen, the two chemicals join
together to form a new compound. This reaction is called an oxidation/reduction
reaction and represents the other (along with acid/base reactions) most common
type of chemical reaction. In an acid / base reaction, a proton (H +)
gets transferred from one substance to another. In an oxidation/reduction
reaction electrons get transferred from one substance to another. In this
reaction iron transfers some of its electrons to oxygen. The iron atom becomes
an Fe+3 ion and oxygen becomes an 0-2ion, which quickly joins with
an H+ion to form water. These two elements combine to form iron
oxide, or rust.
During the corrosion process, irondoes not seem to react with air at all. Water is necessary for the oxidationreaction to occur, to facilitate transport of the
electrons, although we doknow that iron will rust in air after a long time, since there are waterdroplets in the air. Another substance that facilitates the
transport ofelectrons is vinegar.
This experiment will test the
corrosion properties of water and vinegar, modeling two of the main
environmental causes of increased rust corrosion. The vinegar is our model for
acid rain. Industrial and auto emission gases create acid rain by making the
rain that falls much more acidic than pure rain water. (Pure rain water has a
pH of about 5.6 from dissolved carbon dioxide, a normal constituent of air;
acid rain can be as acidic as to have a pH of 3!) Acid rain is not only a
problem in urban areas with lots of industry and cars because winds can blow
the polluting gases far away before they return to the earth as acid rain. We
observe from this experiment that acid rain would accelerate the corrosion
process of iron, i.e. the "steel" wool in vinegar will corrode more
quickly than the steel wool in water or in dry air.
As an introduction to this
experiment, have the students brainstorm about ways to test the reaction
between iron and oxygen. Talk about what iron and oxygen are, and have the
students list some places they are found in our environment. Iron oxide, or
rust, is found as a reddish-brown color. If students suggest metals that are
not iron, you can talk about how some metals react with oxygen to create
compounds that are different colors of "rust''.
Objectives:
1.
2.
3.
4.
To thoughtfully set up an experiment to demonstrate and
test the chemical reaction between iron and oxygen.
To critically observe and record observations.
To write a standard lab report including
clearly-conveyed hypotheses, observations with variables, and conclusion.
To know some ways the chemical reaction between iron
and oxygen is present in, and affects our daily lives.
Vocabulary: Only to be used in write up. Do not Define
Chemical Atom Iron Oxygen Reaction Molecule
Materials:




3 small containers
water (This experiment demonstrates the reaction
between the oxygen in the air and the "steel" wool, which is
facilitated by water. This reaction works best if the water used has been
sitting around a while. Iron should not rust in water if there is no
oxygen present, i.e. the reaction is between oxygen and iron, in the
presence of water. However there is a lot of oxygen dissolved in water,
especially when it comes directly from the tap. Iron will rust in the
water, and make it appear as if iron is rusted by water alone, without the
presence of oxygen. When water sits around for a while. it becomes
"flat" as the dissolved oxygen leaves it. The white vinegar is
pretty ' flat" as is.)
white vinegar
super-fine iron wool (This can be found in paint stores
or hardware stores; supermarkets normally sell steel wool (Brillo), which
is stainless steel and resists rust!)
Procedure:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Set up three containers, label oneWATER, oneVINEGAR,
and oneNOTHING.
Add approximately 50 ml of water to the container
labeled WATER.
Add approximately 50 ml of vinegar to the container
labeled VINEGAR.
Add nothing to the third container labeled NOTHING.
Place a small piece of iron wool into each beaker. For
the container with liquid, stretch out the wool and place it in the container
so some of the wool is below the surface of the liquid and some is above
the surface of the liquid.
Create an educated purpose, hypothesis and data table with variables.
Observe the beakers overthree days. If you observe changes in the iron wool, are the
changes the same below the liquid, at the surface of the liquid and above
the liquid?
Record observations.
Create an analysis and conclusion.
Conclusion Talking Points:
-Pictures of experiment
-Describe places where rust is
common and not so common.
-Suggest everyday examples of this
reaction. One idea would be to talk about how corrosion evidence would be
different near and far from bodies of water.
-Recommend materials that could be
used for shrouding in today’s society to prevent corrosion and why these
materials are better.
SCIENCE CONTENT STANDARD #1:
THE NATURE OF SCIENCE for grades
5-8: "collect and summarize data from an experiment and interpret the
results in terms of the data."
SCIENCE CONTENT STANDARD #2:
PHYSICAL SETTING for grades 5-8:
"understand that the cycling of water in and out of the atmosphere plays
an important role in determining climatic patterns. Water evaporates from the
surface of the earth, rises and cools, condenses into rain or snow, and falls
again to the surface. The water falling on land collects in rivers and lakes,
soil, and porous layers of rock, and much of it flows back into the ocean.
SCIENCE CONTENT STANDARD #5:
DESIGNED FOR grades 5-8: "discuss
how and why science and technology have created synthetic (non-natural)
materials."
Cross-references:
This experiment can be tied most
clearly to an environmental science unit on acid rain, as well as a chemistry
unit on oxidation/reduction reactions. Because rust corrosion is such a part of
our industrial life, there are many ways in which technology has approached
this problem. This direction could take you into a lesson on science
information and technology (looking at why paint has zinc in it to prevent
rusting, etc). The effects of rusting have also had great effects on history,
geology and our knowledge of the past, through the corrosion of historical
evidence, which could be incorporated into a more interdisciplinary approach to
the subject.