8th Grade Performance Task
Contributed by: RAND
Designed by: University of California, Santa Barbara, Stanford University, and The Far West Laboratory

Description:

In the third part of Acids and Bases - Vinegar, entitled "Text," students read about an experiment conducted by another but does not use any apparatus. In that experiment, the student uses a Universal Indicator Color Guide to measure the strength of acids and bases, as well as what happens when acids and bases are mixed together. Additionally, the student decides which of three solutions of unknown pH will neutralize a fourth solution of unknown pH. Students have to apply this process to a problem involving a vinegar and an unknown vinegar solution.

This task assesses students' abilities to describe and illustrate equipment, describe independent variables, introduce variable names, include diagrams, provide descriptions and illustrations, describe results, synthesize results in a table, graph, or diagram, and draw conclusions about the experiment and relationship found.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Properties and changes of properties in matter

Performance Expectations:

• organizing and representing data
• formulating conclusions from investigational data
• applying scientific principles to develop explanations and solve new problems

National Science Education Standards:

8 B PS 1: Properties and changes of properties in matter: Grades 5-8
1.2 Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. In chemical reactions, the total mass is conserved. Substances often are placed in categories or groups if they react in similar ways; metals is an example of such a group.

8 A SI 1: Abilities necessary to do scientific inquiry: Grades 5-8
1.4 Develop descriptions, explanations, predictions, and models using evidence. Students should base their explanation on what they observed, and as they develop cognitive skills, they should be able to differentiate explanation from description — providing causes for effects and establishing relationships based on evidence and logical argument. This standards requires a subject knowledge base so the students can effectively conduct investigations, because developing explanations establishes connections between the content of science and the contexts within which students develop new knowledge.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

General Instructions to the Teacher:

Students will be working individually for the experiment/activity part of this exercise.

The materials should be set out at each lab station, if possible. A central supply area, if needed, should be easily accessible. All supplies should be clearly labeled.

Materials:

No materials are needed for this exercise, other than Acids and Bases - Form T.

Advance Preparation:

None

Safety:

Extensions and Modifications:

Acids and Bases Vinegar II and III