8th Grade Performance Task
Contributed by: New York State Education Department (NYSED)
NYS Alternative Assessment in Science Project (1996)
Description:
Students observe two types of interactions in a
sealed plastic bag. One bag contains baking soda and water, and
the other baking soda and vinegar. Students will determine what
evidence indicates that a chemical change is occurring.
This task assesses students' abilities to make simple
observations, develop descriptions and explanations of phenomena,
and apply that understanding to an additional hypothetical situation.
This task is designed to take students approximately
10-15 minutes to complete.
Overall Task Content Area:
Earth Science
Specific Knowledge Areas:
Properties and changes of properties in matter
Performance Expectations:
- conducting investigations
- gathering 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.
1.8 Use mathematics in all aspects of scientific inquiry.
Mathematics is essential to asking and answering questions about
the natural world. Mathematics can be used to ask questions; to
gather, organize, and present data; and to structure convincing
explanations.
(Use the "hot" link on the PALS home page
to check the full text of related National Science Education Standards,
if desired.)
National Council of Teachers of Mathematics:
Algebra (AL1): Understand patterns, relations and functions.
Problem Solving (PS2): Solve problems that arise in
mathematics and in other contexts.
General Instructions to the Teacher:
This task is designed to take students approximately 10-15 minutes
to complete.
Students may work individually or with groups during this exercise.
Students should be ready to work as soon as the period begins.
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 for "Chemical Changes":
-
1 lb box of baking soda
- 1 quart of white vinegar
- small cups or containers
At this station students should have:
- 2 resealable bags labeled A and B
- 2 twist ties
- 1 plastic teaspoon
- 50 ml graduated cylinder
- baking soda
- white vinegar
- water
- paper towels
- safety goggles
Advance Preparation:
- A 1 pound box of baking soda and one (1) quart of vinegar is
sufficient for a class of approximately thirty (30) students.
- A supply of baking soda and vinegar in small labeled containers
must be placed at each student station.
- The resealable bags may be washed and reused.
- Use a 'good' brand of vinegar. Not all vinegars have the same
acid content.
Safety:
- Check MSDS (Materials Safety Data Chart) for further laboratory
precautions.
- Laboratory safety procedure is required.
- Safety goggles must be worn during this experiment.
- Be aware that the baking soda and vinegar bag will expand greatly
due to the carbon dioxide production.
- Be careful.
- Teachers and students should always exercise appropriate safety
precautions and utilize appropriate laboratory safety procedures
and equipment when working on science performance tasks.
Extensions/modifications:
None
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