Chromatography is used to separate mixtures of substances into their components based on small differences in solubility of different molecules. To begin the process, you must dissolve a substance (called the mobile phase) into a second substance (called the stationary phase). The mobile phase flows through the stationary phase and carries the components of the mixture with it, which usually travel at different rates. Molecules that are the most soluble will move the furthest and the least soluble will travel the shortest and are measured in retention time. The water itself is able to move up the paper due to the properties of water creating Capillary Action.

In paper chromatography, the stationary phase is the paper and the mobile phase is the water. If using the same color but with different brands, it is easy to see that the same color is not always made of the same mixture. A black from Brand X may contain more red compared to Brand Y which may have more green or blue.

Determining the components of a mixture are important because it allows scientists to know what is in a mixture and how to recreate it (such as in medicine if a new mixture is found in nature) or how to alter it (such as if a mixture is toxic to people, chromatography can help determine what is making it toxic).

Using these techniques, you will be able to create flowers perfect for the April showers to bring the true flowers in May!

Key Terms

Chromatography – process for separating components of a mixture

Mobile Phase – the substance that moves and is dissolved into the stationary phase

Stationary Phase – the substance in which the mobile phase is carried through; the substance that stays still through the process

Soluble – able to be dissolved

Retention Time – the amount of time it takes for a substance to travel a certain distance

Capillary Action – the ability for a liquid to flow in narrow spaces without the assistance, or even in opposition to, external forces like gravity.

Supplies

- Coffee Filters OR Paper Towels

- Pipe Cleaners OR Pencils OR Pens OR Straws OR Paper* (it is also possible to do this experiment without these materials)

- Scissors

- Water Based Markers

- Tape

- A Cup

- Water

- Towels OR Paper Towels

Step 1: Make a Design

Open the coffee filter and make a design as desired with markers on top of a piece of paper or washable surface as the color can bleed through onto the surface. Of using paper towels, cut the size of the circle out and decorate as desired. Designs in the center will have a higher chance of washing away into the water and darker colors will appear more vividly.

Step 2: Fill the Cup With Just Enough Water to Submerge the Bottom Center of the Filter.

Step 3: Place the Decorated Filter Into the Cup With the Middle Touching the Water.

Step 4: Watch the Water Move Upwards.

Watch as the water moves upward and moves the color with it. The entire process may take 5 or minutes to go through the entire filter. Leave in for at least 2-3 minutes to ensure even spreading of the ink.

Step 5: Remove Filter

Remove the filter from the water and place onto a towel/paper towel to dry. Restart the process if desired to make a bouquet of flowers. Be sure to replace the water after each filter as the color from the previous flower may remain in the water and change the color of the next.

Step 6: Once Dry, You May Fold the Filter Into Forths and Cut Off the Top to Make a Petal Type Design If Desired.

Step 7: Create Your Beautiful Flower With the Colors of Chromatography!

Fold the filter in half and then in half again (fourths) and use tape to attach the stem to the flower. The stem is not required. Be as creative as you want when working to make it look fuller by adding tape inside to hold the petals out. If using paper to make the stem, roll the paper into a small tube and secure with tape before putting the flower together.