This Is a Lesson in MODELING: Not Creating a Model, but Evaluating a Model

Teacher Notes

This is a lesson in MODELING: not creating a model, but evaluating a model.

1.  Run journaled demo.

2.  Have students rate the balloon as a model for a marshmallow 1-5, and line up that way. Then count off 1-5 or so into groups, so all groups have a mix of opinions.

3.  Each group is to generate a list of STRENGTHS and WEAKNESSES of using a balloon to model the marshmallow.

4.  Report out.

5.  Make the points:

a.  ALL models have strengths and weaknesses.

b.  The role of a scientist is to choose the best model for the problem under study, always remembering the model’s weaknesses. Models are TOOLS to guide us in making sense of what we see – in generating questions, in testing ideas.

6.  (?) Have groups generate questions about what’s going on in the marshmallow through use of the model (may need to start with one).

7.  ASIDE: Students may generate ideas on elasticity, and “discover” the materials science concept of (in)elastic deformation – if so, praise them and point it out!

Name:

Date: Class:

Journal Response

Marshmallow Demonstration

1.  Predict: What will happen to the balloon in the bell jar as air is removed from the bell jar?

2.  Observe: What did happen?

3.  Predict; What will happen to the balloon when air is let back into the bell jar?

4.  Observe: What did happen?

5.  Explain these observations in terms of the kinetic-molecular model of gases. INCLUDE SUBMICROSCOPIC DRAWINGS.

6.  Predict: What will happen when a marshmallow is placed in the bell jar and air is removed?

7.  Observe: What did happen?

8.  How is a marshmallow like a balloon? How is a marshmallow not like a balloon?

9.  Is a balloon a good model for a marshmallow? Why (not)?