The "tie-dye" look utilizes Sharpie markers (permanent ink), rubbing alcohol and a cotton t-shirt. The t-shirt designers (i.e., kids) draw a small design with the markers and then drip rubbing alcohol on the ink. The alcohol makes the marker bleed to create a watercolor effect.
The kids experimented with different ink patterns - dots, thicker circles, lines and even letters. Then they dripped alcohol onto the ink and watched it spread to the final watercolor design.
I learned a bit about chemistry while researching this t-shirt decorating technique because I knew the kids would want to know why the markers were affected by the alcohol but not the water. It peaked my curiosity as well. After some time searching the web, I found a few complicated explanations about the chemistry behind the effect. I believe I grasped the basic idea. But, it turned out the trickiest part of presenting this project to the club yesterday was breaking down the chemistry explanation in a way that all the kids would understand.
Here's my oversimplified, non-chemist explanation of the basic science behind this t-shirt making technique.
It involved a simple chemistry concept of chemical compounds and their electrons.
There are some chemicals that dissolve in water but others do not.
Sharpie markers contain permanent ink. The chemical in the ink does not dissolve in water. When you wipe permanent ink with water, it does not remove it.
But if you wipe permanent ink with isopropyl "rubbing" alcohol, it breaks down the ink and it appears to dissolve in the alcohol.
The reason this happens is because of a chemical reaction between polar and non-polar electrons. When two non-polar elements get together, they try to wipe each other out.
In this experiment we used Sharpie markers, which are non-polar. Because water is polar, it doesn’t affect the marks made with a Sharpie marker (hence it being labeled "permanent"). But the rubbing alcohol is non-polar and can make the molecules of another non-polar compound move around. So when you drip some alcohol on the marker, you can see the color change and start to disappear.
Another example of a non-polar compound is oil. This is why water and oil do not mix. They stay separate because the polar affect of the water forces the non-polar oil to clump together. In other words, the (polar) water can not join or change the (non-polar) oil.
So when you see a product package that says “water insoluble,” it means the chemical compound in the package has non-polar molecules that can not be changed with water. But in some cases - when you know it is safe and won’t create a more scary chemical compound (like toxic fumes or an explosion!) - you can clean up or remove that chemical compound with alcohol.
Sharpie markers = non-polar
Rubbing alcohol = non-polar
"Washable" Crayola makers = polar
Water = polar
Polar dissolves polar
Non-polar dissolves non-polar
Don't you feel like a chemist now? I know the kids loved the results of their new scientific knowledge. They were all quite pleased with their creative - and colorful - results.
I should mention that rubbing alcohol has a strong odor so best to do this project in a well-ventilated area.
No comments:
Post a Comment