How Do Fireworks Get Their Colors?

deymos, iStock / Getty Images Plus
deymos, iStock / Getty Images Plus

Want to impress your friends in the midst of a fireworks display? Wow them with your knowledge of basic chemistry and let them in on the secrets to the rainbow beauty of the night sky on the Fourth of July.

Small pellets, charmingly named "stars," are the key to the fireworks's colors, EarthSky reports. The stars are filled with different combinations of metal salts that each add a bright color to the firework when it explodes.

Different chemical elements correspond with different colors: strontium carbonate for red, calcium chloride for orange, sodium nitrate for yellow, barium chloride for green, and copper chloride for blue. Purple fireworks are created much like you might create purple paint—by mixing red and blue.

According to LiveScience, when you light the fuse on the outside of the fireworks's thick tube, the flame ignites a pouch of black powder inside known as the lift charge, which causes the shell containing the stars to catapult into the air. As it rises, a time-delay fuse begins to burn within it and, by the time it reaches its maximum height, the shell bursts, causing the stars inside to color each strand of the explosion.

Paul Nicholas Worsey, fireworks expert and professor of mining and nuclear engineering at the University of Missouri at Rolla, told LiveScience that red and green are the easiest colors to create, while blue is more difficult. Worsey says gold is best if you want your firework to keep its color for a long time, maybe even until it hits the ground.

The trick behind those especially crowd-pleasing fireworks that change color after they explode is simple: The stars are simply coated in multiple metal salts. Once you see the firework’s second color, that means the stars burned through their outer layer and reached a different metal salt—kind of like licking a Gobstopper.

For another way to impress your friends this fireworks season, learn the names of these 10 fireworks effects so you can call them out as they burst.

[h/t EarthSky]

Amazon's Under-the-Radar Coupon Page Features Deals on Home Goods, Electronics, and Groceries

Stock Catalog, Flickr // CC BY 2.0
Stock Catalog, Flickr // CC BY 2.0

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Now that Prime Day is over, and with Black Friday and Cyber Monday still a few weeks away, online deals may seem harder to come by. And while it can be a hassle to scour the internet for promo codes, buy-one-get-one deals, and flash sales, Amazon actually has an extensive coupon page you might not know about that features deals to look through every day.

As pointed out by People, the coupon page breaks deals down by categories, like electronics, home & kitchen, and groceries (the coupons even work with SNAP benefits). Since most of the deals revolve around the essentials, it's easy to stock up on items like Cottonelle toilet paper, Tide Pods, Cascade dishwasher detergent, and a 50 pack of surgical masks whenever you're running low.

But the low prices don't just stop at necessities. If you’re looking for the best deal on headphones, all you have to do is go to the electronics coupon page and it will bring up a deal on these COWIN E7 PRO noise-canceling headphones, which are now $80, thanks to a $10 coupon you could have missed.

Alternatively, if you are looking for deals on specific brands, you can search for their coupons from the page. So if you've had your eye on the Homall S-Racer gaming chair, you’ll find there's currently a coupon that saves you 5 percent, thanks to a simple search.

To discover all the deals you have been missing out on, head over to the Amazon Coupons page.

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The Reason Supreme Court Justices Wear Black Robes

Judge Thomas Patrick Thornton (left) is sworn in as a federal judge by Judge Arthur F. Lederle (right) on February 15, 1949.
Judge Thomas Patrick Thornton (left) is sworn in as a federal judge by Judge Arthur F. Lederle (right) on February 15, 1949.

Professional attire can go a long way in communicating the level of respect you have for your occupation and the people around you. Lawyers don’t show up for court in shorts and politicians don’t often address crowds in sleeveless T-shirts.

So it stands to reason that the highest court in the country should have a dress code that reflects the gravity of their business, which is why most judges, including judges on the Supreme Court, are almost always bedecked in black robes. Why black?

As Reader's Digest reports, judges donning black robes is a tradition that goes back to judicial proceedings in European countries for centuries prior to the initial sitting of the U.S. Supreme Court in 1790. Despite that, there’s no record of whether the Justices went for a black ensemble. That wasn’t officially recorded until 1792—but the robes weren’t a totally solid color. From 1792 to 1800, the robes were black with red and white accents on the sleeves and in the front.

It is likely that Chief Justice John Marshall, who joined as the fourth chief justice of the Supreme Court in 1801, led the shift to a black robe—most likely because a robe without distinctive markings reinforces the idea that justice is blind. The all-black tradition soon spread to other federal judges.

But according to former Supreme Court Justice Sandra Day O’Connor, there is no written or official policy about the robes, and the Justices are free to source them however they like—typically from the same companies who outfit college graduates and choir singers. It’s certainly possible to break with tradition and arrive on the bench without one, as Justice Hugo Black did in 1969; Chief Justice William Rehnquist once added gold stripes to one of his sleeves. But for the most part, judges opt for basic black—a message that they’re ready to serve the law.

[h/t Reader’s Digest]