Quick Take on ... Chemical Changes

Chemical change is a difficult concept to teach middle school students because of the level of abstraction required. Physical Science Content Standard B of the National Science Education Standards states students in grades 5-8 should investigate materials' differences with respect to properties such as boiling and melting points and solubility. Further, they should be able to define element and compound operationally, based on observation, rather than theoretically, based on atomic theory. Therefore, an experience-based, constructivist approach is recommended.

Here are a few resources that enable students to construct operational definitions of elements and compounds and distinguish between them.

Acids and Bases: Kitchen Chemistry
http://www.teachersdomain.org/resources/phy03/sci/phys/matter/zkitchen/index.html
Acids and bases react with other chemicals in predictable ways. This interactive activity allows you to conduct virtual experiments on various solutions to determine if they're acidic or basic. In one experiment, you can test the acidity of different household substances by trying to launch a virtual cork rocket.

 

Sunscreen and SPF Ratings
http://terrificscience.org/ncw/2007/pdf/Sunscreen.pdf
This activity uses the concept of color change to detect chemical change. To put a greater inquiry spin on the activity, you could ask students what SPF stands for on sunscreen bottles. Why is sunscreen used at all? Allow students to complete step one as described, but then ask how these beads might be useful in testing sunscreens. Allow students to identify a control, an experimental design, and a data-table format, with your coaching. Finally, students can infer whether the sunscreen used in the experiment remains the same as it was before the experiment. They should provide evidence to support their inferences.

 

Handmade Paper
http://www.exploratorium.edu/exploring/paper/handmade.html
This activity is labor intensive and requires preparation, but the experience and products are sure to provide a lasting impression on students. At each step of the process students can say whether that step represents a chemical change and they can state their evidence to support their claim. A side benefit of this activity is its connection to sustainability.

 

Brought to you by the staff at the NSDL Middle School Portal - http://msteacher.org.

Copyright December 2007 - The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0424671. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Copyright December 2007 - The Ohio State University - http://creativecommons.org/licenses/by-nc-nd/2.0/. This material is based upon work supported by the National Science Foundation under Grant No. 0424671. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.