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Science Rocks!


Paper Towel Chromatography

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Sent in by:
Emily of Gaithersburg, MD

Solve this note-worthy mystery!
Materials

Materials Needed


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

Instructions

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!

Some of your Results

Randy, age 8 of Lincoln, CA wrote:
I tried a Sharpie marker and a black marker. The Sharpie marker lots of black and a little of violet. The marker burst out in blues, purples and grays.

Alaya, age 12 of Springfield, MA wrote:
it was soooo cool!!! the colors staarted changing really fast I used a crayola Black marker and th color went from the original blak to brown to blue to realy light green! it was EPIC!

Spencer, age 8 of Aurora, CO wrote:
The water went up and the ink turned brown!

Naazneen, age 11 of Harvey, IL wrote:
out of the 2 differet colered markers 3 differet colors came out. I the crayola marker it was blue purple ad gray. out of the rose art colored marker was gree blue ad a liitle bit of purple.

Sarah, age 9 of Yarmouth, ME wrote:
I put the paper towel on a black ink marker and when I put it in the marker, the ink turns purple and the black ink stays there in the water.

Donna of Marlton, NJ wrote:
The towel changed different colors

Fafa, age 10 of Los Angeles, CA wrote:
When I tried Paper Towel Chromatography for the first time, it didn't work. So I tried it with a marker and then it worked. It is so cool how it shows the different colors of a pen/marker. -It doesn't work with different color markers/pens.

Elizabeth, age 11 of Mcallen, TX wrote:
it was really cool because we saw lots of colors in just one black pen.

Kayliegh, age 13 of NY wrote:
im doing this as a school science fair project. I didnt use water I used nail polish remover and a black ball point pen and the black seperated into yellow pink and a light blue.

Athena, age 12 wrote:
Why is blue ink more soluble in water than other primary colours?

Zuhayr, age 9 of Toronto, ON wrote:
The marker line started rising and it formed awesome colours. It was so cool!

Cecille of Batangas, Philippines wrote:
it turns to blue its lovely when I observed.. but why my some other classmates the chromatography is more than one color?..

Lily, age 9 of Nelson wrote:
i am doing paper chromatography for a school science project. its going well. I did it with smarties instead of coloured pens. its going really well! I used chromatography filter paper.

Esmeralda of San Antonio, TX wrote:
When I put the marker blot in the water with the paper towel, it looked a little blue.

Allexcia of New York, NY wrote:
I had used three differnt blue markers and a black permenat marker. The markers I used was a blue Expo dry erase marker, the second marker I used was a blue Crayola marker and the third marker I used was a blue Sharpie. The crayola quickly spread and light blue at the bottom oof the paper and a hint of green. the blue sharpie only spread a little and had light blue. the expo didnt spread at all. the black permenant marker had light purple at the bottom.

Ice, age 12 of Forks, WA wrote:
I tried this by using different colored markers. It's like the water's absorbing the ink and it was so cool the color disappeared in about 20 minutes!

Allison, age 15 of Augusta, GA wrote:
We did something like this in chemistry at school. We each brought in a T-Shirt, and put dots on it in a circular pattern using colored permanent markers and dropped isopropanol (rubbing alcohol) into the center of the circle. The colors spread out into a cool circular pattern. I didn't know how to make my circles big, like other people did. So my designs were small but it still turned out pretty cool.

Candlisous of Las Vegas wrote:
the different pens had different inks in them some blue some green it was pretty cool

Brenda, age 16 of OH wrote:
it changes like grey orange yellow and blue

Parker, age 7 of Flagstaff, AZ wrote:
I used washable markers, white coffee filters. I drew dots and they expanded when I dropped water on them; the green dot had a ring of blue and pinch of yellow. This is awesome!!! Oh YA the colors spread at diffrent speeds. Besides learning chromatorgraphy I now have a new technique for my Art projects.

Keileigh, age 10 wrote:
i repet DONT use ball point it needs to be reguler or it wont seperate I looked it up any ways it worked graete

Emily, age 13 of Springfield, OH wrote:
I do not see the point of this project. It was fun but there was no point

Celina of Murfreesboro, TN wrote:
the black pen and the green expo worked best.

Chase, Spencer, Sadie, Josh of TN wrote:
3 did nothing one showed slight change and the last one completly changed

Kayley, age 9 of Murfreesboro, TN wrote:
The ink went all over the paper towel

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.


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