Description:

Students determine which of three beverage samples contains the most vitamin C. They then apply their understanding to an additional situation.

The task assesses students' abilities to make simple observations, collect and organize data, and apply their understanding to an additional situation.

This task is designed to take students approximately 20-30 minutes to complete.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Not Available

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 A SI 1: Abilities necessary to do scientific inquiry: Grades 5-8

1.1 Identify questions and concepts that guide scientific investigations. Students should form a testable hypothesis and demonstrate the logical connections between the scientific concepts guiding a hypothesis and the design of an experiment. They should demonstrate appropriate procedures, a knowledge base, and conceptual understanding of scientific investigations.

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.

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.

(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:

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
Grades 9-12 m. understand histograms, parallel box plots, and scatter plots and use them to display data

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

General Instructions to the Teacher:

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 "Vitamin C Testing":

• pen
• labels
• plastic cups
• beverages of various concentrations of vitamin C
• indophenol

At this station students should have:

• 3- 5 oz. plastic cups labeled Test A, Test B, and Test C
• 3- 5 oz plastic cups labeled Control A, Control B, and Control C
• 3 beverage samples marked A, B, and C
• 6 stirrers
• 3 eye droppers
• 10 ml graduated cylinder
• indophenol solution (60 ml dropper bottle)
• paper towels
• safety goggles
• water

Advance Preparation:

• Use beverages that have a large, definite difference of vitamin C content to facilitate the qualitative decision of color change made by the students.
• Purchase, or prepare, a 1% indophenol solution by dissolving 1 gram of indophenol in 99 grams of water.
• Label all cups as indicated in the materials list.

Safety:

• 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.
• Safety goggles must be worn while completing this task.
• Students must be reminded NOT to taste any substance used in this task.
• The salt form of indophenol should not be used by students as it has been identified as a potentially hazardous material. Have MSDS sheets available.
  

Extensions/modifications:

• N/A