You have learned that mixtures are a physical combination of two or more substances. The substances in a mixture retain their unique chemical properties and can be separated by physical means. Filtration, boiling, distillation, and decantation are ways to separate mixtures. Another method is called chromatography. Chromatography was developed in 1910 by a Russian botanist named Mikhael Tsvet. Its name comes from two Greek words – chroma (color) and graph (writing). In chromatography, a mixture is passed through a special gas or liquid. The different substances in the mixture are attracted to the gas or liquid in different ways. The substances that are the least attracted separate from the mixture the fastest. The substances that are the most attracted take the longest to separate. Chromatography is used by biochemists in labs and even forensic scientists at crime scenes. It can be used to analyze the substances in pollutants, separate blood proteins, and determine the ingredients in a flavor or scent.

OBJECTIVES
Use chromatography to separate the colors in different markers.
Directions
If you are unable to do this experiment hands-on, please watch the animation below of the experiment then answer the following questions.

SHOW TRANSCRIPT
Questions
Answer the following questions in the essay box.

Describe what happened to each marker line. Draw each filter strip.
Were any of the markers pure colors? If so, which ones?
How do you think the experiment could be changed to separate non-washable markers?

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Transcripts
Chromatogram Experiment

For this lab, you need a clear plastic cup, coffee filters, scissors, wooden stick or pencil, tape, water and washable markers.

[A cup with a pencil laying on the rim of cup horizontally.] Cut a 1 to 2-inch wide strip from the center of each coffee filter, and attach it to the wooden stick or pencil. Place the filter strip in the cup so the craft stick lies across the top of the cup.

[Black marker] Fill the cup with about half an inch of water. Trim the bottom of the strip so it just touches the bottom of the cup. Remove the filter strip from the cup. Choose a marker and draw a line across the strip about 2 inches from the bottom.

[Colors appear on paper strip.] Allow the water to begin to move up the coffee filter. Record your observations Remove the strip from the cup and let it dry.

Now we will repeat the process using a new filter strip and a different marker. Record your observation on this marker’s result

Continue until all markers have been tested.

[Red marker] Now we will repeat the process using a new filter strip and a different marker. [Colors appear on paper strip.] Record your observation on this marker’s result

[Orange marker] Now we will repeat the process using a new filter strip and a different marker. [Colors appear on paper strip.] Record your observation on this marker’s result

[Yellow marker] Now we will repeat the process using a new filter strip and a different marker. [Colors appear on paper strip.] Record your observation on this marker’s result

[Green marker] Now we will repeat the process using a new filter strip and a different marker. [Colors appear on paper strip.] Record your observation on this marker’s result

[Blue marker] Now we will repeat the process using a new filter strip and a different marker. [Colors appear on paper strip.] Record your observation on this marker’s result

[Purple marker] Now we will repeat the process using a new filter strip and a different marker. [Colors appear on paper strip.] Record your observation on this marker’s result

Questions
Answer the following questions in the essay box.

Describe what happened to each marker line. Draw each filter strip.
Were any of the markers pure colors? If so, which ones?
How do you think the experiment could be changed to separate non-washable markers?