How Do Fireworks Get Their Colors?

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

Want to impress your friends while you wait for this year’s fireworks display to begin? 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]

15 Frequently Asked Questions About Coronavirus and COVID-19

National Institute of Allergy and Infectious Diseases-Rocky Mountain Laboratories, NIH, Flickr // Public Domain
National Institute of Allergy and Infectious Diseases-Rocky Mountain Laboratories, NIH, Flickr // Public Domain

The new coronavirus and the disease it causes, COVID-19, is officially a pandemic. People in every U.S. state and more than 160 countries are infected. And although it’s highly contagious, it’s also possible to recover from its respiratory symptoms—in fact, recovery numbers are steadily increasing around the globe.

As we wait for the new coronavirus to run its course, it’s good to stay informed. This no-nonsense, panic-free FAQ answers some of your most pressing questions.

1. What is the new coronavirus?

The new coronavirus is the same type of virus that causes the common cold and flu, as well as more serious illnesses like SARS and MERS, and this new one is extremely serious. It causes a respiratory disease called COVID-19 (which is an abbreviation of Corona Virus Disease 2019). The virus emerged in Wuhan, China, in December 2019. It has since spread throughout the world. People who get the virus can be asymptomatic, feel like they have a cold or flu, or have complications causing pneumonia and possible death. It spreads from person to person through infected droplets when a person coughs, sneezes, or exhales. You can catch it by touching a surface that an infected person touched, or being in the direct path of their droplets.

2. Can my pets be infected with the new coronavirus, or can I catch it from my pets?

Although a dog in Hong Kong tested positive for the new coronavirus, the possibility of transmission between pets and their owners is still relatively unknown. Aside from this infected dog—which was never actively sick, even though the dog’s owner was—there have been no other reports and no evidence of transmission from person to pet, or vice versa.

Remember, though, that your pet's toys or food bowl “could potentially have the virus on it,” Monya De, an internist in Los Angeles, tells Mental Floss. “Can they go lick the neighbor kid, and the neighbor kid has disease, and they then transmit it to you? I’d be more worried about surfaces.”

3. How long does the new coronavirus stay on various surfaces?

We don't know for sure, but the World Health Organization (WHO) does note that it can stay on certain surfaces for a few hours up to a few days, similar to previous coronaviruses. A recent study, published in the New England Journal of Medicine on March 17, found that the virus is detectable on these materials for these durations:

Aerosols: three hours
Copper: four hours
Cardboard: up to 24 hours
Plastic: two to three days
Stainless steel: two to three days

The CDC recommends cleaning frequently-touched surfaces often—including doorknobs, phones, faucets, and light switches—with a regular household cleaner or wipe. It probably wouldn't hurt to blast your Amazon deliveries with a disinfectant spray before opening them, too.

4. Does drinking alcohol kill the new coronavirus?

No, not even a little. Alcohol may kill the virus on surfaces when it’s in sanitizer, but it won’t work for your own body. “When you consume alcohol, it immediately starts to break down in your GI tract,” De says. “It has much more chance of causing liver damage and damage to your mucous membranes over time. The alcohol is broken down before it has the chance to sterilize your body in any way.”

5. Do I need to wash all my food?

Probably not, unless you saw someone sneeze on, breathe on, cough on, or manhandle your groceries. Coronaviruses are spread from person to person through infected respiratory droplets. There’s no evidence of the food itself transmitting the disease. But it doesn’t hurt to be sanitary: Wash your hands before handling food, wash your fruits and vegetables as you normally do, and cook everything to the right temperature.

6. How is COVID-19 different from the flu or a cold?

COVID-19 symptoms are frustratingly similar to the common cold and flu. Here’s what symptoms you should expect, depending on what virus you have.

COVID-19: Slowly developing fever, cough, fatigue, shortness of breath
Cold: Sneezing, aches and pains, runny or stuffy nose, sore throat
Flu: Rapid-onset fever, cough, fatigue, aches and pains, headache

7. If I’m unlikely to become seriously ill, is it OK to go outside?

Nope. People of any age are able to catch the virus, and you may be asymptomatic and have the disease without knowing it. Staying inside and away from other people is the only way to stop the spread at this point. Even if you don’t think you’ll get sick, someone you come in contact with could, and they could be immunocompromised—meaning it would do far worse harm to them than to you. If you absolutely must go out, keep a distance of about 6 feet between you and anyone else.

8. Are most serious cases of COVID-19 in the elderly?

Most serious cases are in people who have compromised immune systems. That means the elderly, plus anyone with an underlying health condition like asthma, diabetes, heart disease, or lung disease—regardless of their age.

9. What are the best protection measures against the new coronavirus?

Wash your hands regularly with soap and water. If you can’t do that, use antibacterial hand sanitizer. Keep 6 feet between you and other people. Don’t touch your eyes, nose, or mouth. Cover your mouth with a tissue or your elbow when you cough or sneeze. If you feel sick, stay home.

10. Can I take antibiotics or a vaccine for COVID-19?

There is currently no treatment or vaccine for the virus. Antibiotics won’t work because they treat bacterial infections, not viral infections. Possible treatments and vaccines are in clinical trials, but it will still be a while before they’re available to the general public.

11. Should I wear a mask?

Only if you’re actively sick with COVID-19 symptoms or treating someone who is. Masks are most important for sick people to wear so they lower the chances of spreading the disease by stopping any infected particles from getting into the air. There’s a worldwide shortage of masks right now, and you shouldn’t use one unless you absolutely have to. Plus, most medical masks available to the general public are single-use and don’t effectively stop the virus from spreading.

12. What should I do if I think I’m sick with COVID-19 symptoms?

If you have symptoms or have been in contact with an infected person, call your doctor. They’ll determine if you need to go to the doctor's office or get tested for the new coronavirus. Plan to isolate yourself until you’re feeling better. Do not go to an emergency room unless you have severe symptoms; you may infect other people there.

13. What’s the proper way to self-quarantine or self-isolate?

If you've been traveling or have had contact with a potentially infected person, experts recommend quarantining yourself to slow the spread of illness. That means staying home, avoiding visitors, washing your hands frequently, and thoroughly cleaning surfaces during the quarantine period.

If you need to self-isolate because you’ve tested positive or are otherwise sick, you should follow strict guidelines. Stay home, put on a face mask, and limit your contact with other people in your household. Do not go out or get on public transportation. Restrict the amount of time you spend with pets, just in case. Continue to cover your mouth with a tissue or your elbow when you cough or sneeze, and regularly wash your hands. Don’t share household items, and clean common surfaces every day. You’ll want to monitor your symptoms, too. If they change or get worse, be sure to call your doctor.

14. Is coronavirus some sort of deep-state conspiracy?

No.

15. How can I maintain a sense of sanity during this pandemic?

Overall, De says, the biggest thing right now is to be nice to yourself. There’s a lot of lingering anxiety right now, and it’s only made worse with social distancing measures and the constant flow of news. She suggests adding daily meditation to your routine, and uninstalling news apps, even if just for a day. Read a book instead of watching TV or playing on your phone. Have a virtual dinner party or movie night, or play board game over Skype.

“There are a lot of ways you can relieve stress and still maintain that personal connection without visiting anyone right now,” she says. “This is really a time to treat yourself to a little escapism.”

The Reason Why McDonald’s Soft Drinks Are All $1—Regardless of Size

At McDonald's, you could probably quench the thirst of a family of four for just $1.
At McDonald's, you could probably quench the thirst of a family of four for just $1.
Mario Tama/Getty Images

If you’ve ever walked up to a McDonald’s counter with the intention of ordering a normal-sized Coke and walked away with a full 32 ounces of fizzy liquid, you’re definitely not alone. Since all McDonald’s soft drinks are $1, it’s hard to pass up the opportunity to upsize your small to a large.

It seems strange that a business would be willing to sell such drastically different amounts for the exact same price, but it’s actually a savvy business tactic. McDonald’s introduced the $1-fits-all promotion for soft drinks back in 2017 as a way to compete with Wendy’s, Burger King, and other fast food chains that had been slowly stealing its customers. According to Reader’s Digest, it worked—sales increased by 4 percent, and the deal became a mainstay on the dollar menu.

Basically, discounted drinks generate revenue by getting you in the door, after which there’s a good chance you’ll end up purchasing something more expensive from the menu, especially with the tantalizing scents of fresh French fries and sizzling Big Macs wafting right to your brain’s pleasure center. And since production costs for soft drinks are so low, McDonald’s can afford to offer them for especially low prices.

But soda isn't the only item offered at a deep discount—McDonald’s has a whole Dollar Menu with food and drinks priced at $1, $2, and $3, which they know they can count on customers to use as a springboard for bigger, better, more costly orders.

[h/t Reader’s Digest]

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