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T-Shirt Chromatography (10 Favorites)

ACTIVITY in Solubility, Intermolecular Forces, Polarity, Covalent Bonding, Solute & Solvent, Intermolecular Forces. Last updated February 27, 2019.


Summary

In this activity, students will learn about solubility, saturation, polarity, and intermolecular forces through chromatography techniques.

Grade Level

High School

NGSS Alignment

This activity will help prepare your students to meet the performance expectations in the following standards:

  • HS-PS2-6: Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.
  • Scientific and Engineering Practices:
    • Analyzing and Interpreting Data

Objectives

By the end of this activity, students should be able to

  • Explain the concept of chromatography.
  • Identify the solute, solvent, and medium used.
  • Understand the concept of polarity.
  • Comprehend difference between polar and nonpolar, as well as the progression from one to the other.
  • Identify the polarity of each of the three components in chromatography.
  • Understand the concept of “like dissolves like” (polar solutions can dissolve other polar solutions and nonpolar solutions can dissolve other nonpolar solutions) through understanding the concept of intermolecular forces (IMFs).
  • Explain that substances are not just polar or nonpolar; there is a range of polarity based on the strength of the substance’s IMFs.
  • Infer why certain colors spread more than others.
  • Interpret why isopropanol is used in this activity instead of water.

Chemistry Topics

This activity supports students’ understanding of

  • Solution
  • Solute
  • Solvent
  • Solubility
  • Saturation
  • Molecular compounds
  • Polar covalent and nonpolar covalent bonding
  • Molecular Polarity
  • Intermolecular forces

Time

Teacher Preparation: 25 minutes

Lesson: 45 minutes

Materials

  • White t-shirt
  • Pipet (disposable pipet preferred)
  • Rubber band
  • Permanent markers of different colors
  • Rubbing alcohol (isopropanol)
  • Receptacle to collect excess isopropanol (like a beaker)
  • Paper towels

Safety

  • Students should always wear safety goggles and aprons when handling chemicals in the lab.
  • Students should wash their hands thoroughly before leaving the lab.
  • When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.

Teacher Notes

  • My school pays for me to buy each student a t-shirt. If yours does not, ask each student to bring in one. As long as it is mostly white, the activity will work.
  • Student must use at least four colors to be able to analyze the possible differences.
  • Designs can be as simple as making dots of color, being sure to saturate the ink on the t-shirt, but it can be as complicated as tying the t-shirt with rubber bands in the same fashion as real tie dye. Then students can color on the t-shirt while it is all tied up, really saturating it with the ink. Once the alcohol has been added, the outcome looks very similar to a real, normal tie dyed t-shirt.
  • It is not about how much surface you can cover with the ink. It is about how much ink you can saturate in any one spot. More color in a particular spot, more spreading of color.
  • Students can be as creative as they like. Some can draw pictures; some can write words; others just imitate the example that I show them with dots of color to create colorful pinwheels that look like the back of CDs.
  • When applying the alcohol to the t-shirt, point the pipet with alcohol in the direction you want the alcohol to travel.
  • Do not use the marker to color on wet alcohol as it tends to dry out the marker very quickly.
  • Any receptacle to catch the excess alcohol can be used. I use beakers since they are readily available in a chemistry classroom.
  • Be sure to use a rubber band to pull the t-shirt taut when applying the alcohol, otherwise the color will not spread well.
  • Misconceptions
    • Many students use the words “polar” or “nonpolar” even when they are not referencing molecular compounds.Molecular compounds are held together by covalent bonds.Be sure they understand that the term “polar” is short for “polar covalent” and “nonpolar” is short for “nonpolar covalent”.
    • Solubility of the solute is based on that substance’s IMFs using the concept of “like dissolves like.”Don’t let students just quote this phrase.They should be able to explain what it means: Polar solutions can dissolve other polar solutions and nonpolar solutions can dissolve other nonpolar solutions through understanding the concept of intermolecular forces (IMFs).
    • All molecules are not just fully polar or fully nonpolar.There is actually a progression or a range of polarity based on the strength of the molecule’s IMFs.Some can be mostly polar while some are only slightly polar.Some can be nonpolar while some are only slightly nonpolar.Students have a hard time recognizing this concept and might need help to reach this conclusion.

For the Student

Lesson

T-Shirt Chromatography Activity

Background Theory

Chromatography is an important analytical tool that is used in research and industry to separate components of a mixture by color. In chromatography, solutes are distributed along a medium by a moving solvent and are separated into their component colors. There are many kinds of chromatography but all have some things in common. First, there is a stationary phase (or medium) that may be polar, attracting polar components, or nonpolar, attracting nonpolar components. In this experiment, the stationary phase is the t-shirt.

The second necessary component is a solvent (the mobile phase) that washes the third component, the solute (the color components in permanent markers), along the t-shirt. This solvent has to be a different polarity than the stationary phase. The components of the solute may be more strongly attracted to the solvent or to the t-shirt, depending on their polarity. As the solvent washes through the t-shirt, the components of the solute spend some time being absorbed on the t-shirt and some time traveling in the moving solvent. Solubility of the solute is based on that substance’s intermolecular forces (IMFs) using the concept of “like dissolves like.”

In this experiment, we will use Sharpie “permanent” markers as the solute and rubbing alcohol (isopropanol) as the solvent.

Objective

To explore the concept of chromatography, the polarity of the components, and discuss the concept of “like dissolves like”.

Materials

  • White t-shirt
  • Pipet (disposable pipet preferred)
  • Rubber band
  • Permanent markers of different colors
  • Rubbing alcohol (isopropanol)
  • Receptacle to collect excess alcohol (like a beaker)
  • Paper towels

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • Wash your hands thoroughly before leaving the lab.
  • Follow the teacher’s instructions for cleanup of materials and disposal of chemicals.

Procedure

  1. Stretch a single thickness of the cloth of the t-shirt over the top of the beaker. Pull the cloth taut and secure it with a rubber band around the outside of the beaker.
  2. Select a Sharpie marker and make a shape or design. Fill a pipet with rubbing alcohol. Slowly drip it into the center of the shape. Continue dripping the rubbing alcohol onto the cloth until the solvent has spread to the desired distance.
  3. Allow the wet section of the t-shirt to dry before putting more ink on it.
  4. Repeat steps 1-3 on different parts of the t-shirt using a variety of colors.
  5. After all of the chromatography patterns have developed, allow the t-shirt to dry completely.
  6. Dispose of any excess rubbing alcohol in the sink and wash it down with lots of water. Rinse out the beaker and pipet with water. Clean up your work area and wash your hands.
  7. At home, you can iron the t-shirt to help set the inks. Wash the t-shirt by hand. Do not put it in the washing machine, as the color will fade.

Post-Activity Questions

  1. What was the solute in this experiment?
  2. What was the solvent in this experiment?
  3. What is meant by polarity of molecules?
  4. Why is isopropanol polar? Why is it less polar than water?
  5. Why is isopropanol used instead of water in this experiment? Explain in terms of solubility, IMFs, and the concept of “like dissolves like.”
  6. What acted as the stationary phase in this experiment?
  7. What acted as the mobile phase that caused the ink to separate in this experiment?
  8. Explain how the components of each ink separate. What can you infer about the molecules making up the color that travels the greatest distance? The least distance? Explain in terms of solubility, IMFs, and the concept of “like dissolves like.”
  9. Predict what would have happened in this investigation if a very polar solvent had been used. Explain in terms of solubility, IMFs, and the concept of “like dissolves like.”