PALS - Administration Procedures

Paper Chromatography

Administration Procedures

Grades 5-8 Performance Task
Contributed by: Council of Chief State School Officers (CCSSO/SCASS)

Description:

This event is designed to illustrate how ink can be separated into its component chemicals using paper chromatography. Five unknown samples of ink on pre-labeled chromatography strips are provided to students. Students use these strips and water as a solvent to separate each ink into its component colors by paper chromatography. Students use their results and understanding of the process to design an experiment which will identify an unknown mixture of inks.

This task is designed to take students approximately 40 to 50 minutes to complete.

Overall Task Content Area:

: Physical Science

Specific Knowledge Areas:

: Matter and its transformations

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 A SI 1: Ability 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.

8 B PS 1: Properties and changes of properties in matter: Grades 5-8
1.1 A substance has characteristic properties, such as density, a boiling point, and solubility, all of which are independent of the amount of the sample. A mixture of substances often can be separated into the original substances using one or more of the characteristic properties.

(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:

MEAS2: Apply appropriate techniques, tools, and formulas to determine measurements:
Grades 6-8 k. select and apply techniques and tools to accurately find length, area, volume, and angle measures to appropriate levels of precision

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

General Instructions to the Teacher:

This task is designed to take students approximately 40-50 minutes to complete.

Students will be working in groups of 4-6 for the experiment/activity part of this exercise. Each student must record the information in his or her own booklet (test papers). Allow 20 minutes to complete the group work. If students are still working together 20 minutes after the testing begins, instruct them to cease their group work and begin individual work. At this point, they may no longer talk. Whether or not they are just beginning their individual work, remind students that they now have about 25 minutes to complete the individual activity.

Students should be ready to work as soon as the period begins. Group assignments should be made in advance. 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 "Paper Chromatography":

At this station students should have:

12 marked and punched chromatography strips
3 unmarked and punched chromatography strips
5 250-ml clear plastic containers
drinking straws
1 black fine tip water soluble marker
tap water
paper towels
1 straight edge per group
1 pen or pencil per student

Advance Preparation:

Chromatography strips must be provided for each student group. Strips must be marked and punched with holes such that they can be hung on a drinking straw (see illustration in student directions.)

Group assignments should be made in advance.

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.