Ever wonder how fireworks… work wonders?

The Fourth of July just isn’t the same without pyrotechnics. And while the inevitable giant fireball from Dad lighting up the grill may be exciting in the moment, I’m actually referring to the giant chemistry demonstration we watch at night.

fireworks

Fireworks are basically a bunch of combustion reactions, which are rapid chemical reactions involving oxygen gas (O2) combining with another substance. These combustion reactions are exothermic, which means energy is released during the reaction in the form of heat, light, and sound.

A firecracker explosion is essentially one large combustion reaction involving black powder or gunpowder, which is made up of potassium nitrate (KNO3), charcoal, and sulfur. Potassium nitrate will provide oxygen to the reaction, while charcoal and sulfur will act as fuel. This reaction produces a lot of gas and heat in very little time, and all of that gas produced needs a place to go. When too much of it builds up in an enclosed space and the pressure becomes too great, you get an explosion.

The basic components of a firework are a fuse, tiny explosives called stars, and a burst charge that triggers the explosion. Precise timing is also helpful.

fireworks2

First, you need an entirely separate explosion to get the firecracker up into the air. Typically to get the whole package airborne, you need what’s called a mortar, a long tube that directs the firecracker onward and upward away from bystanders. This explosion needs to be very controlled so you don’t set off the second firecracker inside, yet strong enough to get the whole package off the ground. A malfunction can have disastrous consequences. You can search for “fireworks fails” on YouTube for some disaster action.

When you light a firework, it’s not just one fuse; it’s two: the fuse that sends the firework up, and a time-delay fuse that is longer and burns more slowly, allowing the firecracker to gain some altitude before the second reaction begins. If the fuse is too short and the firecracker doesn’t fly high enough before exploding, it can get noisy (not to mention dangerous.)

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Once the time-delay fuse expires, the stars begin to explode. A burst charge will explode and expel the stars, spreading them out. The stars themselves may have different chemical components within, but the basic idea is still a combustion reaction. There is some sort of fuel reacting with oxygen and producing a lot of gas and heat.

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All those colors you see come from burning metals, which produce different wavelengths of light when heated. I don’t know how many of you have tried to burn metal before, but I can tell you from experience, it’s not easy.

We model this particular combustion reaction in one of our ConocoPhillips Science On Stage Outreach programs! Since lighting a firecracker in a school is a terrible idea, in Cool Chemistry, we use a fuel and some granular chloride salts in a beaker. When I light the fuel, I am beginning a combustion reaction that releases a lot of heat and will burn the metal salts.

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The red/pink flame is from the metal lithium, sometimes used in batteries. You’ll notice that in this photo, there is a large Nalgene beaker covering the beaker that used to be full of green flames. That Nalgene beaker is airtight and cuts off the flow of air in and out of the beaker. When this happens, no new oxygen is allowed to enter; once the combustion reaction has used all of the oxygen inside the beaker, the flame will be put out.

Our beaker simulation doesn’t produce the loud bang we often associate with fireworks because it is open to the air around it. The boom heard is actually all of the gas building up inside of the firecracker being expelled all at once, moving faster than the speed of sound, just like the pop heard when a balloon bursts.

One prevalent legend says fireworks were invented accidentally by a Chinese cook some 2,000 years ago, and the basic concept has remained the same over the years. If anything, precise timing of explosions in fireworks shows has made the spectacle all the more enjoyable.

So grab some apple pie, pull out a lawn chair, relax and enjoy the world’s most famous combustion reaction, celebrating America’s birthday in style!

Bring the wonders of the Houston Museum of Natural Science straight to you with HMNS Outreach! To book a presentation of Cool Chemistry, email outreach@hmns.org or call (713) 639-4758!

LaB 5555 this Friday: Steep yourself in culture, say oolong to the stress of the week and TEA off with The Tontons

Today’s blog comes to us from Te House of Tea owner Connie Lacobie in advance of our tea-themed LaB 5555 this Friday, Feb. 8, featuring musical guests The Tontons! Steep yourself in the culture of tea from 7 to 8 p.m. before you hit the dance floor by reserving tickets here.

Tea was first discovered in China about 4,000 years ago, but it was not until 400 to 600 A.D. that was tea heavily demanded and mass cultivation started to fit market demand. The Chinese used tea as a medicinal drink mixed with onion, orange, ginger and other spices.  It was considered a precious gift to the Emperor and nobles only.  Around 479 A.D., Turkish merchants began trading tea around the Mongolian borders.

In the 700s, tea was introduced to Japan by Lu Yu, who wrote the first definitive book about tea. This tome, The Classic of Tea, attracted the interest of Zen Buddhist monks in Japan, and tea began its journey to the East. From the 600s to the 900s, between the Tang Dynasty and Sung Dynasty, matcha green tea powder was the most commonly used and traded tea to India,Turkey and Russia and was transported via horse, donkey and camel caravans.

Steep yourself in the culture of tea at LaB 5555 this Feb. 8!

During the Yuan Dynasty under Mongolian Emperors, tea was a common drink. But even though Marco Polo had ample contact with the dynasty, he did not bring back tea to Italy and the country missed its chance to earn a fortune. After the Mongolian reign, whole leaf steeping was widely used in favor of matcha, and black tea and oolong tea processing began.

A few hundred years later, toward the end of the Ming Dynasty, European missionaries started to land in Asia to spread Christianity to the East. When they returned west, they brought back new knowledge about the benefit and pleasure of drinking tea.

It wasn’t the tea-loving Brits who first encountered the beverage, however. The first European known to encounter tea was the Portuguese Jesuit Father Jasper de Cruz, who documented his experience in 1560. Dutch traders became the first Europeans to bring tea back to the west, and they profited immensely from selling this exotic beverage. The Portuguese and the Dutch collaborated in the tea trade from China, carrying the valuable merchandise to other European countries.

In 1662, Charles II married Catherine Braganza of Portugal, who loved tea and made it the most common beverage drink in England — even above alcohol. As demand increased from the west, annual tea trade was recorded in British diplomat Harry Parkes’  Report on the Russian Caravan Trade from China. Russian Caravan Tea (lapsang souchong) was documented as having been exchanged for small furs, like squirrels. Teas began traveling annually through Kiakhta, Mongolia to Russia via the Silk Road, then from Russia to the west. The Dutch started to compete against the Portuguese in the tea trade, which motivated the English empire to join an alliance with the Portuguese.

Queen Elizabeth I appointed the East India Company to control all trading business with the East. The company used India as a base to extend its ambitious influence to China, where it introduced and encouraged opium sales. Not long afterward, the Qing government attempted to crack down on opium use and smuggling in Canton and other southern provinces. However, because China had less military prowess and technology at its disposal, China lost most struggles during these “Opium Wars,” and ultimately lost Hong Kong to the English in 1842. Following that, China was scrambled by eight different European countries, with each occupying one or more provinces.

Can you believe the tea trade could lead to the scramble for China and the collapse of the Qing Dynasty?

As the demand for tea continued to grow, the English spread tea plantations to their colony in India. Nearly every region touched by the English Empire was influenced by tea.

This included the New World, where the English, being envious of Dutch success in the  area, decided to try to monopolize the tea market in New England. They passed The Tea Act in 1773, which led to Boston Tea Party and the American Revolution.

Imperialism in the 1900s even brought tea to Africa, where plantations were established in Uganda, Kenya and Malawi. Even today, tea is the second-most common beverage, second only to water, because of its history and reputed benefits.

The Tontons
LaB 5555’s featured musical guests, The Tontons

Learn all the political and social implications of the tea trade at LaB 5555 this Friday and then dance it out to the music of local favorites The Tontons — and be sure to check out their new single, out this month!

Last chance to see Terra Cotta Warriors — EVER! Hurry in before the army moves out Sept. 3

There may have been a Terra Cotta Warriors II, but — mark our words — there will not be a Terra Cotta Warriors III.

HMNS’ second special exhibition of the exquisitely detailed and distinct warriors that guarded the tomb of China’s First Emperor, Qin Shihuang, extends the story of the Qin, Han and Tang dynasties with 200 ancient works of art, including newly-discovered artifacts unearthed from imperial, royal and elite tombs.

golden dragon

The stunning exhibition — which also featured the premiere of a Terra Cotta Warrior with its original green paint still intact, thanks to new conservation techniques — closes Sept. 3.

What better way to celebrate Labor Day than to examine up-close the extreme care that went into each warrior’s individualized features, the fine ornaments and sacred objects, or the extraordinary works of art?

TCW II: Warriors, Tombs and TemplesHMNS is open from 9 a.m. to 6 p.m. from Sept. 1 through Sept. 3. Click here for tickets.

Flickr Photo of the Month: Trappings of Yingpan Man [Dec. 2010]

Trappings of Yingpan Man. 3rd - 4th century
Trappings of Yingpan Man. 3rd – 4th century by cybertoad, on Flickr.
Posted here with permission.

There are some amazing photographers that wander the halls of HMNS, and when we’re lucky, they share what they capture in our HMNS Flickr pool. This month, we’re re-starting a series where we’ll share one of these photos on the blog each month.

Elaine (cybertoad on Flickr) took this photo during a Flickr meetup in our current Secrets of the Silk Road exhibition. From the photographer:

The Beauty of Xioahe may have been the exhibit’s celebrity but the Yingpan Man still captured me. His simple funerary mask with the delicately painted eyebrows and the gold leaf evoke a sense of elegance and peace that I hope he carried with him into the after life.

Inspired? Most of the Museum’s galleries are open for photography, and we’d love for you to share your shots with us on Flickr, Facebook or Twitter. Check out the HMNS photo policy for guidelines.

Photography is prohibited in this exhibition during general hours. If you’d like to join one of our Flickr meetups, check out our Flickr group Discussions page for updates on upcoming events.

Want to see Yingpan Man for yourself? Secrets of the Silk Road is only on display for a few more weeks!