The Simple Science of Static

Anyone with a dryer knows that static cling happens when you spin clothes around together in a hot, dry tub for an hour. But did you know that your grade nine science textbook explained why? I was amazed to discover a whole page of useful, everyday science, right there in my ninth-grader’s homework! Now, if only ninth graders and laundry had anything to do with one another...
If you’re still putting those chemical-coated dryer sheets in with your family’s laundry, this is for you. If you’re finding those rubber or wool dryer balls kinda help, but don’t quite cut it, this is for you.
It turns out that you don’t need to add anything to your load to cut static cling; you need to take something out.
The (Simple) Science: Static electricity is generated when two different types of materials, with different propensities for holding positive (+) or negative (-) electrical charge, rub against one another. Friction! The two materials adhere, or cling, to one another. When they’re pulled apart a charge is produced, due to the flow of electrons from one material into the other.
Way back in Ancient Greece, Thales of Miletes was polishing a piece of amber with a swatch of rabbit fur, when he noticed that the amber suddenly attracted feathers and dust to itself. Presto! Static electricity was discovered. Flash forward 2600 years or so, to your laundry room and the experiment looks like this: your kids’ polyester fleece PJ pants rub against your nylon blouse in a hot dryer for an hour. Yowza! You’d best stand on something rubber before you pull those two apart.
In the years between Thales’ day and laundry day, scientists like Johan Carl Wilcke experimented with different types of materials, and discovered that they have varying tendencies to become positively charged, or negatively charged. They created an sequenced list of materials, called the Triboelectric Series. This series lists materials in order from + to - charge, and contains a lot of fun materials like rabbit fur, rubber balloons and human hair. For our purposes though, let’s focus on fabric.
The further apart two fabrics are in the Triboelectric Series, the greater the static zap created by rubbing them together in your dryer. While there are different opinions on the exact order of the materials in the series (particularly around the order of silk, wool and cotton) the series looks something like this:
+ leather, nylon, silk, cotton, wool [0] rayon, polyester/fleece -
As I mentioned, the farther apart two fabrics are from each other in this series, the more static electricity will be generated by rubbing them together. Now, you likely don’t put leather, silk, or wool in the dryer (and if you do, stop it; that’s just wrong.) But if you machine-dry cotton, rayon and polyester, a simple change will make a big reduction of static cling in your laundry. Avoiding static cling is as simple as sorting your fabrics before drying.
What about those wool dryer balls? While it’s true that wool carries no charge (or very little, anyway) and they might fluff up your load, and eliminate some of the charge, but they’re not the whole solution. The real culprit seems to be the mingling of polyesters and cottons in a hot, dry place.
What’s the takeaway, for laundry day? Take your family’s PJ pants and basketball shorts out of the dryer. Use the dryer for heavy cotton towels, joggers and tees. Polyester air dries so quickly anyway, it’s really not a big deal to hang fleece, poly and rayon pieces on the line or clothing rack. No dryer sheets required.
You’re welcome! Now, back to the homework.