Students manipulate opaque, sealed containers in an attempt to describe the container's contents.
Models are based on real observations and are useful in explaining and predicting other behaviors of the system. Because many "things of science" cannot be observed directly, indirect evidence often must be used to produce a model. For example, atoms cannot be seen directly; their structures have been inferred from observations of their properties and behaviors.
Day One. Ask students to bring in a small box or can with a lid, and materials to place in it.
Day Two. Students secretly place their materials in their boxes or cans. Before sealing the box or can, each student should make a list of contents for the instructor. After sealing the box, each student should also carry out the experiment with his/her own box and complete the report form. The report form should include three parts: observations (the indirect evidence); theories (interpretations based on the indirect evidence); and drawing conclusions (what is inside) including a sketch to describe the object. Mark each box or can with an identifying letter or number.
Day Three. Exchange the boxes or cans with students across the room or with a different class. Each student analyzes a box or can and complete a new report form. If time permits, students experiment with more than one mystery box. Collect the report forms.
Day Four. Give the completed report forms to the students who made the models, and have those students evaluate the observations and interpretations. Observations are often reported that the student who made the mystery box had never considered. Theories must follow logically from the observations. Drawings must reflect the theories. Collect the evaluated reports.
Review the concept of a model. Have the students give other examples of models.
Name ___________________________ Class _______
Teacher__________________________
DoChem 001 Mystery Boxes
Box Number/Can Number ___________
To generate hypotheses.
Provided by students:
Teacher preparation time: 1 hour to run off data sheets, obtain and set out materials
Procedure time: 1 hour
Class Time: Small part of 4 days required.
Hazardous materials might be placed inside the boxes.
Return the boxes to the students, or save them for reuse.
Model Can Number = 22
Observations:
Interpretations:
A magnetic metal object is inside. Gentle shaking does not loosen the object, but rough shaking does. Once loose, the metal has a chance of getting back onto the magnet.
Sketch:
This experiment was designed decades ago to help students confront science studies in which the structures of systems are inferred from observations of properties. In this activity, the input from the sound and feel of a sealed container allows one to infer the contents of the box. In chemistry we use many observations to help us build models for systems that cannot be directly observed, such as the structure of an atom.