Grades 9-12 Performance Task
Contributed by: New York State Education Department (NYSED)
Developed through University of Buffalo and NORC (1991)

Description:

Students will plan, design, and carry out an experiment to determine an empirical formula for a hydrated salt X that will tell students when all the water has been removed from hydrate crystals.

This task assesses students' abilities to develop procedures for investigation, plans for recording and organizing observations, collecting high quality observations and data, calculating the coefficient of H20 in the empirical formula of hydrated salt X, and making conclusions consistent with scientific principle and the collected data.

This task is designed to take 80 minutes to complete - 30 minutes for Part A (Experiment Design) and 50 minutes for Part B (Experiment).

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Chemical reactions

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data
• formulating conclusions from investigational data
• applying scientific principles to develop explanations and solve new problems

National Science Education Standards:

12 B PS 3: Chemical reactions: Grades 9-12
3.1 Chemical reactions occur all around us, for example in health care, cooking, cosmetics, and automobiles. Complex chemical reactions involving carbon-based molecules take place constantly in every cell in our bodies.

12 A SI 1: Abilities necessary to do scientific inquiry: Grades 9-12
1.2 Design and conduct scientific investigations. Designing and conducting a scientific investigation requires introduction to the major concepts in the area being investigated, proper equipment, safety precautions, assistance with methodological problems, recommendations for use of technologies, clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other than the actual investigation. The investigation may also require student clarification of the question, method, controls, and variables; student organization and display of data; student revision of methods and explanations; and a public presentation of the results with a critical response from peers. Regardless of the scientific investigation performed, students must use evidence, apply logic, and construct an argument for their proposed explanations.

1.3 Use technology and mathematics to improve investigations and communications. A variety of technologies, such as hand tools, measuring instruments, and calculators, should be an integral component of scientific investigations. The use of computers for the collection, analysis, and display of data is also a part of this standard. Mathematics plays an essential role in all aspects of an inquiry. For example, measurement is used for posing questions, formulas are used for developing explanations, and charts and graphs are used for communicating results.

1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.

(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:

NO3: Compute fluently and make reasonable estimates:
Grades 9-12 n. develop fluency in operations with real numbers, vectors, and matrices, using mental computation or paper-and-pencil calculations for simple cases and technology for more-complicated cases
Grades 9-12 o. judge the reasonableness of numerical computations and their results

AL3: Use mathematical models to represent and understand quantitative relationships:
Grades 9-12 f. draw reasonable conclusions about a situation being modeled

MEAS1: Understand measurable attributes of objects and the units, systems, and processes of measurement:
Grades 9-12 m. make decisions about units and scales that are appropriate for problem situations involving measurement

DAP1: Formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them:
Grades 9-12 l. understand the meaning of measurement data and categorical data, of univariate and bivariate data, and of the term variable

PS2: Solve problems that arise in mathematics and in other contexts:
Grades 9-12

COM1: Organize and consolidate their mathematical thinking through communication:
Grades 9-12

REP1: Create and use representations to organize, record, and communicate mathematical ideas:
Grades 9-12

General Instructions to the Teacher:

This task is designed to take students approximately 80 minutes to complete.

Students will be working individually 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 "Hydrated Salt":

• 1 crucible with cover
• 1 pair of crucible tongs
• 1 porcelain triangle
• 1 tripod
• balance
• bunsen burner with matches
• heat resistant tile
• hydrated sample X
• access to a periodic table
• safety goggles
• calculator

Advance Preparation:

None

Safety:

• Safety goggles must be worn at all times
• Hot objects must be handled with tongs at all times.
• Should skin contact occur, flush thoroughly with water.
• 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