Oobleck - What State's the Matter

Sharon Jensen, RTR High School, Tyler, MN; Probe: Uncovering Student Ideas In Science,
by: Page Keeley, Francis Eberle, and Chad Dorsey (NSTA Press)
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Summary

Students will investigate what constitutes a solid and a liquid state of matter. Using the probe, students' misconceptions on states of matter will be exposed. The lab, which uses a cornstarch, water and food coloring mixture, will be explored. The students will determine how that exploration will take place and devise a procedure to determine the state of matter. Students will then, as a group, present their findings to the class. After all the groups have presented their findings, the groups with the same findings will combine and defend their findings to the other group(s) until the class, as a whole, has reached a consensus.

Learning Goals

Students will use critical thinking, data analysis, quantifying and communication skills. Through the whole process the students will generate a basic definition of the states of matter and through those definitions they will further their understanding of states of matter.

Context for Use

This is mainly a lab exploration that will take approximately three 50 minute periods. One day will be for the probe which will expose misconceptions, the pre-lab and the designing of the lab procedure. The second day will be the actual lab procedure and data taking. The third and final day will be the presentations and class "defense" of findings. This high school lab has minimal safety concerns and the set-up is quick and easy. Prior to this lab the students will have had practiced designing and doing their own lab procedure based on the given task. Also prior to this lab, the students will have practiced observation skills and collecting data into forms that are easy to understand at a glance. This activity will occur in the chemistry portion of physical science. This lab can easily be done in a variety of settings and the biggest draw-back is the mess that can, and often does occur.

Description and Teaching Materials

Use Probe (see attached) to assess student understandings and misconceptions. Then pass out a small container of Oobleck (see attached) to each student group and give them 5 minutes to observe. Then pose the question, "How can you determine what state of matter Oobleck is?" The students will determine the procedure they will follow on the second day, what data they will collect, and how they will present that information to the rest of the class. On day two, the student groups will follow their procedure. On the third day, each group will present their findings to the class, and then groups with similar findings will defend their findings. By the end of the period, the groups should reach some basic agreements on concepts. [file 'Oobleck - how to make']

Teaching Notes and Tips

For a group of 24 students, a full container of cornstarch will be needed. Any food coloring will work but I prefer the darker colors. An ice cream bucket works well for mixing. You may need to mix with your hands to get a good consistency and that consistency will loose moisture if it is not covered. You can add more water to it - or less water depending on which state of matter you want them to target. Lighting the substance on fire will produce a slight smell, but nothing terrible or toxic. Make sure the surface is clean to start and then the Oobleck can go back in the ice cream bucket and can be used over several times. Clean-up is easy with water and a large bath towel! In the past, I have not used the Probe to introduce and try to find misconceptions, and I have not had a formal defense of findings.

Assessment

I will use this website to set up my assessment:
rubistar.4teachers.org

Standards

9-12. I. B. 1 design lab;
9-12. I. B. 4 lab errors and effects:

References and Resources