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.

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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.

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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!

Geology Rocks! How I got involved with Occidental Petroleum

by Tania Campbell

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Here I am hiking the world famous Permian Reef Trail at the Guadalupe Mountains National Park to study carbonate rock outcrops.

I’ve worked as a production geologist for 11 years for Occidental Petroleum, and while that is a long run with one company in the energy industry, it has gone by fast. I remember being introduced to rocks in middle school, but by the time I was in high school, I was more interested in marine biology. I then went on to successfully complete a dual bachelor’s degree in marine science and geology, which laid the foundation for understanding carbonate rocks and basic geologic principles, starting me down my path as a production geologist.

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The Miami Circle, where American Indians carved a circular structural support out of bedrock limestone.

The first community project I got involved in that I attribute as a catalyst to my geology interest was working with an archaeological site called the Miami Circle. Approximately 2,000 years ago, American Indians used the bedrock limestone to carve out a perfect circle to support a structure. As a volunteer I only found a few animal artifacts, but I was most interested in the exposed limestone.

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A sample of core that has been cut and slabbed after it was taken from the subsurface in a well. A geologist will describe the rock types and features observed, and other interpretative data is combined to make geologic models and maps.

There are so many different kinds of specialties in geology that sometimes it can feel overwhelming trying to figure out what you want to do. I kept an open mind and set off to learn more with a master’s degree at a different school. It is highly recommended that geologists have their master’s if they want to work in the petroleum industry. I studied hydrogeology and petroleum geology for my master’s, which has helped me work better with team members from engineering backgrounds and develop further in my core profession of doing reservoir characterization. My role involves describing and modeling the layers of rock in the subsurface to predict the most favorable areas for continued secondary and tertiary hydrocarbon recovery.

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Hiking with other geologists through the canyon cuts to map the rock types and observe vertical stacking of the layers of carbonates and siliciclastics.

I am extremely thankful for my education and the career opportunities that have brought me to a place where I enjoy coming to work. Every day there is a different problem to tackle. Sometimes it requires communicating with engineers and understanding other types of non-geo data, or sometimes I need to go on a field trip to an outcrop or a core lab to visualize what the rocks could look like in the subsurface. Or Maybe that day I make maps of the reservoir. It is forever changing in the geology profession.

About the author: Tania Campbell is a production geologist with Oxy Permian Enhanced Oil Recovery, a global corporation partnered with the Houston Museum of Natural Science’s Girls Exploring Math and Science (GEMS) program to help educate girls through hands-on science activities and outreach.

Mark Your Calendars for these events happening at HMNS 6/29-7/5

Bust out your planners, calendars, and PDAs (if you are throwback like that), it’s time to mark your calendars for the HMNS events of this week!

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Lecture – Climate And The Demise Of Maya Civilization By Andre Droxler
Monday, June 29
6:30 p.m.
Climate conditions in the Maya’s time can be retrieved from the earth revealing that climate conditions influenced the destiny of the Maya. Geological data from Belize’s Central Shelf Lagoon and Blue Hole, areas proximal to where Maya Civilization thrived and then abruptly collapse are revealing that weather—rainfall fluctuations and frequent tropical cyclones—may have forced the Maya to abandon their sophisticated cities. Dr. André Droxler of the Center for the Study of the Environment and Society at Rice University will explain how Earth science is helping decode the history of the Maya. A special evening screening of Fate of the Maya in the Burke Baker Planetarium at 6 p.m. and 8 p.m. is complimentary for lecture ticket holders.

Lecture – The Threat Of Asteroid Impacts By David Kring, Ph. D.
Tuesday, June 30

6:30 p.m.
In 2013 the world was riveted by the impact of an asteroid near the Russian town of Chelyabinsk, where over 1,000 people were injured. It was an eerie reminder of another, bigger, impact event that flattened a forest near the Tunguska River in Siberia on June 30, 1908 – and a modern-day example of the immense dinosaur-killing Chicxulub impact event in the Yucatán. Dr. David Kring of the Lunar and Planetary Institute will describe how these types of impacts events have scarred Earth in the geologic past, the magnitude of their persisting threat today, and the steps we might take to mitigate these types of calamitous events in the future. A special evening screening of Impact in the Burke Baker Planetarium at 6 p.m. and 8 p.m. is complimentary for lecture ticket holders to help celebrate Asteroid Day 2015.

Take Two: Close Encounters Of The Third Kind (1977)
Friday, July 3
7:00 p.m.
After an encounter with a U.F.O., a line worker feels undeniably drawn to an isolated area in the wilderness where something spectacular is about to happen.

 

 

Sam Lam: Legacy Camper

Once in a while, the Houston Museum of Natural Science Xplorations program gives children so much enthusiasm about science that they never really leave the museum. Sam Lam discovered the museum as a child with the Xplorations program, and has since never missed a summer at the museum. She now teaches some of the same summer camps she enjoyed when she was a kid.

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HMNS: When did you start attending summer camp here? And why?

SL: I started attending camps at HMNS when I was 6 or 7 years old, around 1998. My mom worked downtown and decided to look into sending us to camp at HMNS. After just one week, I was hooked. From that point on, I kept pestering her to sign me up for Xplorations year after year. 

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HMNS: What was your favorite class? What made it your favorite? Any stories from that class?

SL: My favorite class was Wizard Science Academy. Reading Harry Potter was a big part of my childhood, so it was very exciting to be able to attend a summer camp that incorporated science with a Hogwarts twist! I still remember dissecting an owl pellet and being convinced it was from Hedwig. I remember having Nicole Temple as my teacher and being so excited that she secretly let me switch out of the house that the Sorting Hat chose for me into the house of my choice.

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HMNS: What is your favorite memory from summer camp?

SL: I took a camp called, “Thrills, Chills, and Disasters” that talked all about physics and the science behind amusement parks. As an end-of-the-week field trip that wrapped up all our learning, we were able to go to Astroworld to see the physics in action. I loved going around and riding rides with all of my camp friends. It was such a unique opportunity that I am lucky to have had!

HMNS: If you could go back to Xplorations Summer Camp for one week this summer, what class would you take and why?

SL: I would definitely sign up for Bedazzled! I have had the best time teaching that camp for the past few years. I think the best part of Bedazzled is the Spa Day on Friday when campers get to dress as comfortable as they’d like and pamper themselves for the day. A day with magnetic nail polish and a nice, relaxing mud mask? Sign me up! 

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HMNS: What made you decide to come back and work at HMNS?

SL: When I was a camper, the Xplorations staff was always so enthusiastic and fun to be around. Because of them, I never wanted to leave camp when my mom came to pick me up. I wanted to keep the fun going and stay with them. When I officially “aged-out” of camp, I knew I wanted to come back and make camp a positive experience for others, just like the staff did for me.

HMNS: How did the Xplorations Summer Camp influence your life?

SL: During the summers, HMNS has been my second home for as long as I can remember and the people I have met there have become like another family to me. Some of the best friendships I have are with people I have met through Xplorations. Thanks to Xplorations and its amazing staff, I was able to meet and teach with fantastic teachers who inspired me to become a teacher myself. The best part of Xplorations Summer Camp is the people you meet—from the awesome campers, to the fun-loving TA’s and teachers, and the always cheerful and helpful education staff. My best memories from camp are because of them.