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Ink Analysis and Thin Layer Chromatography (TLC) Lesson Plan

Purpose:

1. To introduce students to thin layer chromatography.
2. To introduce students to the component parts of ink.
3. To provide students with an opportunity to apply science with laboratory experience.

Student Objectives:

1. Students will be able to explain the process of TLC.
2. Students will be able to identify at least three components of ink.
3. Students will be able to analyze data and make conclusions based on laboratory observations.

Materials Needed:

1. Lab Handouts
2. Homework
3. Lecture Notes
4. 3 sources of ink (Same color) - Bic, Papermate, and Sharpie brands could be used
5. Sample Writings
6. Chromatography Paper
7. Pencils
8. Stapler
9. 2:1 propanol:water
10. Petri dishes (half per group)
11. Plastic Cups - disposable (1 per group)
12. Rulers
13. Scissors
14. Water alcohol mix to extract ink

Anticipatory Set:

1. Journal entry or Warm-up question: "What is ink made of/"
2. Set up crime scene - "A check was stolen from the principal's office yesterday. The check later showed up in the athletic office. The principal always uses the same ink pen to write checks. Two suspects have been found. Your task is to analyze the ink pens of the principal, the suspects, and three known samples. You will compare, by thin layer chromatography, the component parts of the ink. With this information, you will be able to determine who stole the check from the principal's office.

Procedure:

1. Complete anticipatory set as described. (Day 1)
2. Hand out TLC Lab Sheet.
3. Collect samples from the forged check.
4. Set up TLC as a class. The teacher should model each step, and then the students will repeat the procedure. The class will move on together.
5. Hand out lecture notes and discuss the characteristics of ink and TLC. (Move onto next step after 20 minutes regardless of progress with notes.)
6. Set chromatography paper out to dry.
7. Finish notes if needed.
8. Analyze TLC findings. (Day 2)
9. Answer lab questions.
10. Handout homework worksheet.
11. Assist students as needed with the TLC analysis.

Adaptations:

1. The lecture can be adapted by providing learning support and lower ability students with a partially completed set of lecture notes. Higher ability students may either be required to fill in more of the lecture notes or may be required to take all notes by hand.
2. No adaptations are required for the lab activity because the lab groups are cooperative and mixed ability.

Closure:

1. Day 1 - Students list the steps of TLC on a piece of paper. This paper will be turned in at the door as the exit pass from the room.
2. Day 2 - Students, remaining in their lab groups, discuss why the different black pens produced different chromatography charts.

Reinforcement Activity:

1. Students will conduct a lab that will reinforce the lecture information.
2. Students will have a homework assignment that uses information obtained from the lab.
Student Evaluation:
1. Students will be evaluated by their lab handout and homework.
2. Students will be evaluated by the final unit project.

Lesson Evaluation:

1. Students will be expected to receive an 80% or higher on their lab and homework.
2. The lesson will also be evaluated at the end of the unit. Students will be expected to receive an 80% or higher on the final lab report.