Paper Towel Chromatography

Sent in by:
Emily of Gaithersburg, MD

Solve this note-worthy mystery!

## Materials Needed

• 5 different black pens (not ballpoint)
• paper towels
• scissors
• bowl filled with one inch of water
• tape

## Instructions

1. Check with a grown-up before you begin.
2. Black ink is black ink, right? Maybe not! Even though the ink from different pens looks the same, it might actually be made of many different dyes. You can separate the dyes in the ink from different pens to make different patterns.
3. First, cut a paper towel into strips about one inch wide.
4. Then draw a squiggly line across a strip of paper towel with one of your black pens, about an inch up from the bottom. Do the same for all the pens, and be sure to label the strips, so you know which strip goes with which pen.
5. Hang the strips over a bowl of water. The water should touch the very end of the paper towel, but not the ink.
6. Tape the paper towels in place and wait to see what happens. The water should creep up the paper towel strips and separate each ink mark into a cool dye pattern. This is called chromatography.
7. Now here's how to use this cool ZOOMsci to solve a mystery. Have a friend or a grown-up write a note on a paper towel using one of the pens, but make sure you don't know which pen is being used.
8. How will you find out which pen was used to write the note? You can compare the patterns from the pens to the pattern from the note to see which pen wrote the note.
9. To see the ink pattern in the note, cut a strip off the note. The strip needs to have ink on one end and no ink on the other end.
10. Put the strip of paper towel in the water just like you did before.
11. Wait until the water creeps up the paper towel strips and separates the ink.
12. Take the strip out of the water and compare it to the patterns you got before to solve the mystery of which pen wrote the note.

Ready for the mysterious sci scoop on how paper towel chromatography works? When the paper towel is dipped in water, some of the water sticks to the paper towel and gets it wet. There's a force between the water molecules and the molecules in the paper towel. That's called adhesion. The water also sticks to itself. That's called cohesion. Both of these sticky forces - adhesion and cohesion - cause the water to travel up the paper towel, moving against gravity. When the water reaches the ink, it dissolves some of the dyes in the ink, and the dyes travel up the paper towel with the water. That's how you can see all the different colors that make up the ink. Try it out with different types of pens. Does a smelly marker make a different pattern than a non-smelly marker? What happens if you use a dry erase marker? Test out your ideas, and send them to ZOOM!

Luciana, age 10 of Queens, NY wrote:
I used ball point pens but nothing happened. I'm wondering if I did something wrong.

Nicolas, age 8 of Laval, QC wrote:
I coloured a piece of paper with a black marker and placed it in the sink which was full of water. The water quickly became blue even though the original colour was black!!!

Abbi, age 15 of Chicago wrote:
We just did a lab like this is my Biology class using leaves to study the different pigments of it. Different shades of green moved up the paper faster than others and we measured them and researched which pigment they were.

Tom, age 11 of Manhattan, NY wrote:
i found out that the pen went cool colors. I held the pen on the paper and it was so cool!!!

Adrean, age 12 of Brooklyn, NY wrote:
I did it with 5 different pens of the color black and no dye spread or anything, it didn't work.

Jackie, age 11 of Ottawa, ON wrote:
I did this experiment in science class and found out permanent markers work best!

Marissa, age 12 of Brooklyn, NY wrote:
It turned different colors. I use different markers like a black sharpie, expo, and bic.

Michael, age 10 of Nampa, ID wrote:
I tested five diffent highlighter's. Four of rose. It was really neat to see.

Maddy, age 9 of WA wrote:
I did it whit marker with a rain bow of colors and they all blended together!!!

Ronnie, age 11 of Rosemead, CA wrote:
I think you should try different kinds of color pens like red, orange, yellow, blue, or purple. Maybe you should try using marker, color pencil, crayon, and anything you guys could think of. I have not try it yet. I don't want to try it yet because I want to know what happens, and I don't want to know first because it won't be a surpise for me.

Samuel, age 9 of Travelers Rest, SC wrote:
When I tried a black ink pens, most of them did not work. One was a "Roller Ball" pen and it worked great! The ink spread out neat when the water soaked up into the word. But the best result was with a regular old black marker. There was green tint along with the black color.

Stephanie of El Paso, TX wrote:
When I tried it it looked as if nothing happened I also tried a gold gel pen still no results!

Jasmine, age 11 of Kennesaw, GA wrote:
When I did this, I used a highlighter. After a few mins. the color was completly gone. Thanks for doing this Zoom sci.

Shahnnon, age 12 of Elkhorn, WI wrote:
I used a washable marker, a permenate marker, and a blue Crayola crayon. The permenate marker worked the best because it turned blue, green, and red. The crayon I think was too waxy because it stayed blue and the regular marker turned brown and blue. I reccomend this experiment to any person interested in chromatography. You could also substitute paper towel for filter paper or baking sheets.

Peyton, age 6 of Big Sandy, TN wrote:
The pen changed different colors like black, yellow, pink, and blue.

Abigail, age 5 of Chittenden, VT wrote:
Very cool experiemnt. We wrote on the papertowels with washable markers. We then dipped the papertowls in water and watched the magic. The ink appeared to be going upwards and blend the colors above.

Allison, age 6 of Lincoln, CA wrote:
The ink turned blue and purplely.

Andrew, age 9 of Renton, WA wrote:
Well I realy didn't use paper towels. I used coffee filters. And the markers I used were visavisa, Mr. skecth black, sharpe red, red marker and Mr. skecth red. The only thing that didn't do anything was sharpe red.

Avigayil & Elisheva of Highland Park wrote:
We didn't have felt tip pens so we used a sharpie. That didn't work on paper towels so we tried on a coffee holder. That didn't work either so we guess we didn't have much luck with that experiment!!

Moses, age 8 of Loxley, AL wrote:
I used markers and pens to write on the paper. I place them in a cup of water. The markers marks on the paper slured and showed the color. The pen marks didn't slur and show the color.

Nachelle, age 12 of Lake Oswego, OR wrote:
It was amazing! When I did a sharpie it spreaded out. I used a purple sharpie and it spreaded out but it also had pink in it. I used other markers some work some dont.

Gina, age 12 of Chicago, IL wrote:
I got all different colors when the water seperated the dyes. It is realy cool because if someone wrote you a secerate admire letter you can take all the suspects pens and match the dyes!

Naomi, age 8 of Ft. Worth, TX wrote:
washable: 3 colors mixed red, yellow, pink 5:14 start 5:14 red turns orange 5:18 can only see orange and Pink

Erika, age 4 of Seattle, WA wrote:
It got green and blue at the top. And the other ones was all purple. Also black and blue at the top.

Michelle, age 12 of West Chester, PA wrote:
When I did it I did it with an dry erase marker and an black crayola marker I found out that the dry erase marker disolves a little bit but doesnt spred. Then when I tried the black crayola marker it came out with a light blue and got to a darker blue. Those were my results.

Jessica, age 11 wrote:
When I tryed using a dry erase markere (an EXPO marker) it didnt do really anything but I ued a color paper towle and those colors mixed.

Brittany, age 15 of Vivain, LA wrote:
I'm a big fan of your show,& I was just watching Zoom & I saw where ya'll did the paper towl Chromatography zoom sci & right after I saw it I just knew I had to try it right away, but instead of useing a black marker I used a red Precise pilot pen & the coolest thing happened... it showed 3 colors pink, white, & I think a little hint of orangey-yellowis color.

Justice, age 4 of Las Vegas, NV wrote:
We tested the Vis a Vi marker, the Sharpie marker and a calligraphy marker. The sharpie stayed black, the vis a vi made a rainbow of purple blue and brown, the calligraphy made purple, blue and orange. It was fun to do this test.

Sarah, age 11 of Kansas City, MO wrote:
When I did this experiment, I used 4 witing things. I used a felt pen, crayola maker, normal pen, pentel pen. The felt pen was the one I wrote the message with it was purpleish. The marker was teal. The reg. did nothing, and the pentel pen was black. I had my sister guess witch one it would be and she said the felt witch was right.

not yet implemented