(Re-post from April 14, 2016)
I love traditional tie-dye, but it’s fun to do this experiment that uses permanent markers and rubbing alcohol to make bright, gorgeous designs that mimic tie-dye, more easily, and with less mess.
This experiment was created by Bob Becker, a chemistry and AP chemistry teacher at Kirkwood High School in Kirkwood, MO. (To find a few of the original experiments I invented, check out Frankenworms, Sugar Cube Fizz Bombs, Homemade Window Stickies, Foaming Slime, and Cornstarch Frescos.)
Here’s a video from my YouTube channel on how to do this experiment, so kids can “watch and do.”
To play with permanent marker tie dye, you’ll need:
-permanent markers (like Sharpies)
-cotton items to decorate, like tee-shirts, socks, or dish towels
-rubbing alcohol (isopropanol)*Read warning labels. Parental supervision is required, since rubbing alcohol is poisonous if swallowed. Do this experiment in a well-ventilated area, and do not expose your artwork to heat until is is COMPLETELY dry, since rubbing alcohol and its fumes are flammable.
-containers like plastic cups or jars
To make your designs, stretch the cotton over the mouth of a jar or cup and secure it with rubber bands. (See video above.)
Use permanent markers to make several dime-sized dots of different colors on the stretched cotton.
Slowly drip rubbing alcohol onto the spots of color until the alcohol starts to soak outward, carrying the ink with it.
Allow your design to dry overnight. When completely dry, hang your shirt in the sun, or put it in the dryer for 15 minutes to set the color. Wash separately from other clothes, just in case!
The Science Behind the Fun: Pigments are molecules that give things color. The pigments in permanent markers are trapped in ink compounds that are insoluable in water, which means that they won’t dissolve in water. However, if you add a solvent, like rubbing alcohol, or isopropanol, to permanent markers, it dissolves the ink. As the alcohol moves through the cloth you are decorating, it carries the pigments along with it. Small pigment molecules move faster than big ones, so the colors sometimes separate into their different color components as they move through the cloth. The alcohol evaporates into the air, leaving the ink in the fabric, and since it is still insoluable in water, it won’t come out when you wash it.
Enrichment: What happens if you draw lines, concentric circles or different shapes on your designs? Can you layer colors and watch them separate? What if you add rubbing alcohol next to the color, instead of directly on it? How many drops of alcohol do you have to add to a dime-sized color spot before it starts to expand?
You can take this project in many different directions, which is what science is all about! Chances are, you already have all the supplies you need for this project in your kitchen: coffee filters or paper towels, magic markers, and water.
Fill the bottom of a bowl or glass with a little water. Then, cut paper towels or coffee filters into long strips. Draw a large dot of color (black works best) about an inch from the bottom of the strip of paper. Place the bottom of the paper, below the dot, into the water. Once the water starts moving, the paper will stick to the side. You can hook it over the top of the glass, like we did.
The water will be wicked up the paper and through the dot, dissolving and taking some of the dye up the strip with it. You’ll be able to see colors separate as the dyes travel up the strip. It’s fun to see what colors make up different black inks. My kids tried it with colors other than black too. They even made dots comprised of several different colors and watched them separate in the water. Another variation is to put ink on a large piece of paper, drip water on it from a dropper or straw and watch the color travel out in a circle!
We taped some of the strips into our science notebooks. They’re very colorful. Older kids might enjoy trying a 10:1 mix of window cleaner and vinegar to separate the colors.
When you separate the colors from one another on the paper, you’re doing chromatography!
When paper is dipped in water, water molecules make it wet. The water molecules travel up the paper towel. 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. Some of the molecules that make up the dye are smaller and travel up the paper towel faster than the larger ones, so you can see some of the different colors that make up the ink separate from one another. The number of spots of color you see can tell you how many chemicals make up the color in your marker.
Most importantly, have fun!