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YouTube // National Geographic
YouTube // National Geographic

What's in Dry-Erase Markers?

YouTube // National Geographic
YouTube // National Geographic

When you think about it, dry-erase markers are kind of magical. They leave marks on a surface easily, but then can be wiped away, leaving virtually no trace behind. The process is of course dry, not involving any liquid to clean up. So how the heck does that work? What's in those markers, and can you make your own?

In this Ingredients video, chemist George Zaidan goes deep on dry-erase markers. His job in this case is a little more complex than usual, because the package doesn't list any ingredients. So with some sleuthing and chemical know-how, he sorts out what's going on, explains it, and attempts to make his own dry-erase compound in his kitchen. Enjoy:

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science
New Clear Coating for Everyday Objects Repels Practically All Liquids
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A new clear coating that is said to repel just about everything—peanut butter included—aims to halt the advance of sticky fingers. Developed by researchers at the University of Michigan, the substance can be applied to a variety of surfaces to keep them smudge- and crud-free, including smartphone and laptop screens, windows, walls, and countertops.

Researchers used algorithms to predict which substances would yield an efficient omniphobic coating, or in other words, something capable of repelling oils, alcohols, and other liquids while remaining durable and smooth. Made from a mix of fluorinated polyurethane and a fluid-repellent molecule called F-POSS, the coating can be “sprayed, brushed, dipped, or spin-coated onto a wide variety of surfaces, where it binds tightly,” according to the University of Michigan’s website.

The team’s findings were published in the March issue of the journal ACS Applied Materials Interfaces. Associate professor Anish Tuteja, who headed up the University of Michigan research team, says it could be a godsend for parents of young tots.

"I have a 2-year-old at home, so for me, this particular project was about more than just the science," Tuteja said in a statement. "We're excited about what this could do to make homes and daycares cleaner places, and we're looking at a variety of possible applications in industry as well."

The team is currently conducting follow-up tests to ensure the coating is nontoxic, but if all checks out, it could find its way into kindergarten classes and daycare centers within the next two years.

Child-proofing everyday objects for the sake of cleanliness isn’t its only potential application, though. The university notes that it could be beneficial to “all industries that depend on the condensation of liquids,” such as refrigeration, power generation, and oil refining.

In recent years, other researchers have set out to create omniphobic coatings, some of which have been successful. However, this undertaking is typically challenging and involves complex synthetic chemistry, according to Chemistry World.

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Food
Why You Never See Fresh Olives at the Grocery Store
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If given a choice, most grocery shoppers prefer fresh produce over something that's been pumped full of preservatives. Yet shoppers are almost never given that choice when it comes to olives. The small, meaty fruits can be found floating in brines, packed in cans, and stuffed with pimentos, but they're hardly ever shipped to the store straight off the tree. As the video series Reactions explains, there's a good reason for that.

In their natural state, because they contain high concentrations of a bitter-tasting compound called oleuropein, fresh olives are practically inedible. To make the food palatable, olive producers have to get rid of these nasty-tasting chemicals, either by soaking them in water, fermenting them in salt brine, or treating them with sodium hydroxide.

Because of its speed, food manufacturers prefer the sodium hydroxide method. Commonly known as lye, sodium hydroxide accelerates the chemical breakdown of oleuropein into compounds that have a less aggressive taste. While other processes can take several weeks to work, sodium hydroxide only takes one week.

Afterward, the olives are washed to remove the caustic lye, then packed with water and salt to extend their shelf life, giving them their distinct briny flavor.

For more on the chemistry of olives, check out the full video from Reactions below.

[h/t Reactions]

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