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Chemical Weathering
Administration Procedures
Grade 5-8 Performance Task
Contributed by: New York State Education Department (NYSED)
NYS Alternative Assessment in Science Project (1996)

Description:

Students will measure the effect of water temperature on the rate of a chemical reaction, similar to the interaction of a weak acid and carbonate rock, using hot water and effervescent antacid tablets.

This task assesses students' abilities to make simple observations, design an experiment, collect, record, and represent data, use mathematics to graph data, make predictions based on the data, relate data from the model to natural materials on Earth, and generalize and infer the data by designing a new experiment.

The task is designed to take students approximately 30-40 minutes to complete.

Overall Task Content Area:

Earth Science

Specific Knowledge Areas:

Structure of the Earth System

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:

8 ASI 1: Abilities necessary to do scientific inquiry
1.2 Design and conduct a scientific investigation. Students should develop general abilities, such as systematic observation, making accurate measurements, and identifying and controlling variables. They should also develop the ability to clarify their ideas that are influencing and guiding the inquiry, and to understand how those ideas compare with current scientific knowledge. Students can learn to formulate questions, design investigations, execute investigations, interpret data, use evidence to generate explanations, propose alternative explanations, and critique explanations and procedures.

1.3 Use appropriate tools and techniques to gather, analyze, and interpret data. The use of tools and techniques, including mathematics, will be guided by the question asked and the investigations students design. The use of computers for the collection, summary, and display of evidence is part of this standard. Students should be able to access, gather, store, retrieve, and organize data, using hardware and software designed for these purposes.

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.

8D ESS 1: Structure of the Earth System
1.3 Land forms are the result of a combination of constructive and destructive forces. Constructive forces include crustal deformation, volcanic eruption, and deposition of sediment, while destructive forces include weathering and erosion.

(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:

AL1: Understand patterns, relations and functions:
Grades 6-8 f. represent, analyze, and generalize a variety of patterns with tables, graphs, words, and, when possible, symbolic rules

DAP3: Develop and evaluate inferences and predictions that are based on data:
Grades 6-8 e.
use conjectures to formulate new questions and plan new studies to answer them

PS2:
Solve problems that arise in mathematics and in other contexts:
Grades 6-8

COM1: Organize and consolidate their mathematical thinking through communication:
Grades 6-8

General Instructions to the Teacher:

This task is designed to take approximately 30-40 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 "Chemical Weathering":

The teacher will need:

  • distribution method for hot H20
  • cooler for ice
  • hot water supply
  • waste buckets

At each station students should have:

  • 3 clear plastic cups (100 ml line marked)
  • 2 Styrofoam cups (approximately 250 ml each) (for transfer of hot and cold H20)
  • 1 thermometer
  • 1 timer
  • 4 effervescent tablets
  • waste bucket
  • paper towels
  • hot, cold, and room temperature H20.

Preparation:

  • Temperatures above 50 degrees Celsius tend to cause the tablet to dissolve so violently that the beaker will overflow. Also, such temperatures are unlikely to occur in nature.
  • Students should be encouraged to use 1-3 tablets.
  • The time when the tablets dissolve should be carefully observed.
  • Teacher needs to mark a 100 ml line on the clear plastic cups.

Safety:

  • Students should be cautioned to be careful using the hot plate and the hot water. Water should not exceed 50 degrees Celsius.
  • Students must not sample the antacid tablets before dissolving them or the solutions that result after the tablets dissolved.
  • 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:

  • Try experiment with different sized pieces of tablet. They could vary in rates of weathering.
  • To target the specific NCTM standard(s) to be measured, ask students to use and compare Fahrenheit and Celsius measurements.

 


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