Indirect Observation

Belvon Walker Frazier School
4027 West Grenshaw Street
Chicago, Illinois 60624


The student will
1. observe the external obscertainer (these are sealed containers that
come with the Lab Aids #100 kit).
2. make hypothesis on internal structure of several obscertainers.
3. retest each hypothesis.
4. check observation again, correct internal structure on each.
5. develop an appreciation of indirect observation and make the
connection between this activity and the historical determination
of the molecular structure of matter.

Material needed:

For a class of 25:
1. 25 sealed obscertainers
2. students worksheets
3. answer sheets
4. crayons


1. Instruct the students not to open the containers.
2. Tell the students that each container has one (1) steel ball inside
each container. They may have none to several internal wall
3. Demonstrate the possible internal wall structure on the board.
4. Give each student four (4) obscertainers. Instruct them to move the
steel ball around carefully by shaking and tilting the obsertainer.
5. Ask students to make a guess about the internal structure of each
obcertainer and to draw this structure on their worksheet.
6. Note that the first guess is called a hypothesis.
7. Tell the students to re-examine each obcertainer and make a second
guess about its structure. Draw each second guess next to the
hypothesis drawing. Call this second guess the "retest".
8. Discuss how much information could be obtained without actually
looking inside.
9. Make a connection between this activity and scientist trying to
determine the structure of molecules and atoms too small to be seen.


Lab-Aids kits can be purchased from the following scientific supply
houses: Central Scientific Company; Fisher Scientific; Wards Biology
Supply. All three companies will furnish catalogues upon request.
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