Thursday, September 10, 2009

Solubility, Capillary Action, Math, and Art

This week we had a combined art and science project, with a little math thrown in for good measure!

You need a white T-shirt, permanent markers, isopropyl alcohol (we used 70% though 90% would be fine too,) a dropper bottle (we used a non-medical syringe,) a large plastic cup, and a rubber band. Here you see the boys posing with their new T-shirts ready to start the project.

Slip the plastic cup inside the T-shirt so the opening of the cup faces towards the front panel of the shirt. On the outside of the shirt, pull the shirt tightly over the cup and put the rubber band around the top to secure it.

Put spots of various colors on the section of the shirt secured to the cup. You can put wavy lines, too, if you like the effect.

Here's the science part. Permanent markers are not soluble in water, but they are in alcohol. Fill your dropper bottle with the isopropyl alcohol and drop in onto the decorated section. Because the permanent marker is alcohol-soluble, the ink "runs." Capillary action moves the ink along the fabric.

Because the syringes are graduated, the boys made up math problems as they went along, like, "Mom, if I had 30 mm of alcohol to start and now I have 10 mm, how much did I use?"

Here are the boys with their finished projects.

We did have a PROBLEM though. I rinsed the shirts in water before washing them, but all the ink washed away. Next time I am going to rinse them well again, then run them through the dryer to evaporate off all the alcohol (it is very volatile, which is why it has such a strong odor) before washing it. The boys have been bugging me to get more shirts ever since.