Chemical and Human Resources, Part I

Kathy Scoggin, Marcy Open School, Minneapolis, MN
Lynne Martin, Maxfield Science, Math & Technology Magnet School, St. Paul, MN

Our venture into history coupled activities for both younger and older students in a unit on chemical and physical changes. The younger children pursued an instructional unit on "Mystery Powders." We selected a several scientists appropriate to the unit and told stories about the scientists during the activities.

The older students conducted research to learn about these and other scientists (both personal and professional items of interest). We had them look especially for how they could actually become that scientist through role-playing. They also looked for a lab activity they could do with younger students to illustrate that scientist's work. They made a "big book" of their scientists. Finally, the older children visited the younger students, set up learning stations for them, conducted historical scientific activities with them, and shared their big book -- while playing the role of the scientist throughout the activity.

Possible extension activities include:

Level: Grades K-6

This curriculum module was developed as part of a project sponsored by Sci-Math-MN and The Bakken Museum and Library. Click to see a directory of other modules using history and philosophy of science.


Mystery Powders

The accompanying instructional unit focused on Minnesota Outcome 7:
Students will learn about the nature of atoms and molecules and the structure of matter by observing patterns in physical properties of objects for purposes of classification.
We adapted the ESS/SCIS Unit "Mystery Powders" for our third graders (each investigation question is keyed): Each of the five lessons is detailed below.


INVESTIGATION QUESTION G3.1
What is matter?

SUMMARY
Learners will observe the physical properties of 5 powdered solids.

MATERIALS
Per student pairs

Per teacher demo PROCEDURE
ACTIVATE
This unit on matter is an investigation into the properties of 5 solids we will call mystery powders. A quick review lesson on physical properties will be necessary. Because we will be working in the field of chemistry as we discuss physical and chemical changes, a brief introduction to chemistry is appropriate in this first lesson. The laser disc lesson on physical changes provides good background for today's lesson.

DISCOVER
We will first need to discuss safety issues surrounding the observation of unknown substances: never taste anything in the science lab unless instructed to do so, how to smell an unknown substance, washing hands after touching unknown substances, the use of goggles to protect eyes, etc. Then use the record sheet to describe how students observe physical properties of the powders. We will observe color, texture, and shape (hand lenses) and record our observations on the record sheet.

INTEGRATE
Discuss observations. Based on these observations, let students make hypotheses about the white powders. What do you think each powder is? Why? What tests could we do to find out about each powder?

Tell stories of scientists who investigated physical properties of substances: Marie Curie, John Dalton (see Historical Chemists below).

INTEGRATIONS
Students find the study of chemistry very intriguing. They enjoy mixing substances and observing reactions because it feels like "real" science. It would be very interesting to do some reading about chemistry and famous chemists. Medical fields rely heavily on the practices and discoveries of chemists around the world, as do environmental scientists, ecologists, biologists, botanists, and many others. Chemistry also has been the subject of great historical events and debates. If you are interested in pursuing such topics beyond our discussions in the lab, let me know. I have many resources and materials to support you.


INVESTIGATION QUESTION G3.2
What happens when each powder is combined with water?

SUMMARY
Learners will observe a physical change when water is added to powdered solids.

MATERIALS
Per student pair

Per teacher demo PROCEDURE
ACTIVATE
Today we are putting the powders into solution: we will add water to each. When we do this we will create a physical change in our materials. The solution will look different than either material did before we created the change, but nothing new is created (during a chemical reaction, a new material is produced and the old materials are indistinguishable). We still have water, we still have the powders, but they are now in solution together. The laser disc lesson helps explain physical change and can be used in introduction or in the integration discussion.

DISCOVER
Monitor student activity for safe practices while using unidentified substances. During clean up, solutions are safe for sink disposal. Assign tables to 1 of the 3 sinks for disposal and cleanup.

INTEGRATE
Discuss observations. What happened with a little powder and a lot of water? A little water and a lot of powder? Were there any differences among physical reactions? Could we reverse these reactions back to dry powder and water? How? It's important for learners to realize that physical changes create nothing new. Cutting paper with scissors, using glue, dissolving Koolaid powder into water, boiling macaroni noodles are all physical changes.

Tell stories of scientists who worked with physical changes: Albert Einstein and the atomic bomb (see Historical Chemists).


INVESTIGATION QUESTION G3.3
What powder properties can we observe by doing an iodine test?

SUMMARY
Learners will observe chemical changes when iodine is added to powdered solids.

MATERIALS
Per student pair

Per teacher demo PROCEDURE
ACTIVATE
Today we're going to learn about chemical change as change which produces a completely new type of matter. The laser disc lesson is a good introduction to the activity. Remind learners about safety rules while working with unknown substances.

DISCOVER
Learners will place a small amount of powder in a mixing cup and drop iodine on the powder, being careful not to touch the powder with the dropper. They will need to observe and record any changes that they see, including color, odor, and temperature.

INTEGRATE
Discuss observations. Iodine is known to indicate a substance called starch by causing a chemical reaction that turns it black. Does this test give us any information about the identity of the 5 powders? If a powder did not turn black after iodine was added, what can we conclude about that powder? The black substance is completely new matter that did not exist before the iodine was added; therefore, the change that occurred was a chemical change.

Tell stories of scientists who worked with chemical changes: Antoine Lavosier (studied one of our mystery powders!), George Washington Carver.


INVESTIGATION QUESTION G3.4
What powder properties can we observe by doing a vinegar test?

SUMMARY
Learners will observe chemical change when vinegar is added to powdered solids.

MATERIALS
Per student pair

Per teacher demo PROCEDURE
ACTIVATE
Today we're going to cause more chemical changes when we add vinegar drops to each powder. The procedure is exactly like yesterday so we'll be dropping vinegar onto each powder in a mixing cup. Record and changes observed.

DISCOVER
Remind learners that they may observe temperature, textural, color and odor changes.

INTEGRATE
Discuss observations. The most prominent reaction is the fizzing of baking soda with vinegar, which also produces an odor (a gas). Now we know that one of the powders is baking soda. The laser disc lesson points out everyday ways that people change matter physically and chemically to make it more useful to them.

Tell stories of scientists who worked with chemical changes: Alfred Nobel and his nitroglycerin.

INTEGRATIONS
The reading lab has a whole series of From...To... books that each describe some process of change, physical and chemical. There are many different ways these books could be used in your reading curriculum. It would be interesting for learners to read the books and determine whether the change described is physical or chemical change.OUTCOME 7: Students will learn about the nature of atoms and molecules and the structure of matter by observing patterns in physical properties of objects for purposes of classification.


INVESTIGATION QUESTION G3.5
How can we use our observation data to identify the white powders?

SUMMARY
Learners will enter data into a spreadsheet matrix and identify each powder.

MATERIALS
Per student pair
Record sheets 1-4
Spreadsheet template on Mac computer

PROCEDURE
ACTIVATE
This lesson will be team taught in the Mac lab by the technology integrator, the classroom teacher, and the science integrator. The lesson has 3 objectives:

  1. To collate data collected in chemistry lab all week into a matrix
  2. To learn to use the spreadsheet component of word processing
  3. To conclude the identity of the 5 mystery powders
We will not complete all three objectives in this one lab period but will continue during Mac lab sessions following this one until our matrix is complete.

DISCOVER
Learners will receive instruction in using spreadsheets. They will then incorporate their own data into the spreadsheets. They can also identify the powders and record from a posted list.

INTEGRATE
From their data, we will create property descriptions of each powder, ie baking soda is a very fine white powder that fizzes with vinegar, does not change with iodine, and doesn't mix well with water. These descriptions represent both physical and chemical properties. For most historical scientists, recordkeeping was laborious at best. Learners now have the power of technology in that we can collate our data onto a spreadsheet and print it out instantly. Scientists of the past would be very impressed!

INTEGRATIONS
Other powders can be tested with iodine and vinegar. Perhaps a homework assignment might include testing flour or cream of tartar or baking powder with vinegar and recording observations. The vinegar record sheet could be used as homework.


Historical Chemists

We focused on the following scientists and incorporated their stories into our lab activities:

JOHN DALTON

1766-1844 Chemist from England who was born color blind. He did the first important investigation to answer his own questions about color blindness and published his conclusions for others to learn from. He also developed the theory that all matter (elements) are made of atoms. He said that each kind of matter has its own kind of atoms, arranged in its own way. That's why each kind of matter has its own special properties.

MARIE CURIE

1867-1934 Through experimentation and perseverence, she identified a certain property that led her to discover a new element: radium. Her dogged determination to learn about this property also was propbably the cause of her death: leukemia probably caused by the radioactivity in the radium. Also, her work was validated in her time only because a man (her husband Pierre) worked with her, lending his credibility at a time in history when females were not considered to be equal partners in the scientific world.

GEORGE WASHINGTON CARVER

1864-1943 Black chemist and naturalist who didn't start school until he was nine years old because he had no parents or money. But he was determined to answer the questions he had about how things work in nature. He was especially curious about plants and he did many investigations with them. He discovered lots of chemical changes that occur in plants, especially the peanut plant and its fruit. His discoveries led to the development of over 300 products that could be made from peanuts! More info

ALBERT EINSTEIN

1879-1955 German chemist who was a quiet shy boy who loved music and math. He was not a magnificent school learner but he taught himself many things outside the classrooms he attended. Most scientists didn't believe his first ideas about atoms and physical changes in matter, and his work was shunned. But later he was proven to be correct. All through his life the ideas he wrote and spoke about were far ahead of what most scientists believed. A champion of peace and a fighter of oppression, this shy and gentle man made discoveries that lead to the development of the atomic bomb.

ANTOINE LAVOSIER

1743-1794 French chemist who revolutionized the practice of chemistry. He liked to study geology and rocks best. He was particularly intrigued by one of the white powders we are studying, plaster, and he spent a lot of time observing its properties. His ideas about gas atoms were very different than what most scientists believed at that time. In fact, he proved the most widely believed property about gases to be wrong! His experiments with the gas called oxygen led to chemical names we use today.

ALFRED NOBEL

1833-1896 Swedish chemist who experimented with a chemical called nitroglycerin, a dangerous material that exploded even when just being handled. He tried many ways to make nitroglycerin safe to use and eventually developed a safe powder which he called dynamite. He wanted dynamite to be used for peaceful activities like mining and construction but eventually it was also used in war. When he died, he left all his money in a fund for prizes to be awarded to people from sience and literature who help mankind, including an award for peacemakers.
Link to activities for older students.