MicroCT of a Sparkler

Image of the Month: Sparkler



Since this Saturday marks the 4th of July, we wanted to join in the celebration. As most people go to see a fireworks show during this time of the year, we decided to have our own celebration a little early. Our warmup to the holiday involved scanning a sparkler. With a burning interest to learn more, a little research, and microCT scanning we bring to light the microstructure of a sparkler.


A Brief History
You light the sparkler and watch the snowball shaped sparks scatter, exciting children and providing a radiant light display. Something so simple such as fire and light still fascinates humans after thousands of years. Though the Chinese are credited for first inventing gun powder and fireworks around 2,000 years ago, it was actually the Germans (though debated) that made the first recorded sparkler. Known as wunderkerzen (quite literal translation of sparkler), they were developed in the 1850’s by using iron and gunpowder paste that was coated over wire3.
Chemical Makeup
Since that time the chemical makeup has changed slightly to produce the sparkler we know today. All sparklers are similar and their chemical composition comprises of a fuel, oxidizer, metal powder and a binder. The fuel is usually charcoal and sulfur, the oxidizer is a chemical such as potassium nitrate or barium nitrate, the metal powder can be iron, steel, zinc, etc., and the binder is usually a slurry of starch and water. There are various compositions available but to explain the process we are sticking to the barium nitrate and iron mixture.
What Causes the Spark?
The process of a sparkler is a chain of chemical reactions that progressively get hotter until the metal powder is hot enough to ignite and spark. Let’s take for instance the one kind of sparkler. The fuel, say charcoal and sulfur and oxidizer such as barium nitrate are mixed to a certain proportion such that the sparkler will burn slowly and not just explode in your hand. What happens is the charcoal, sulfur, and barium nitrate mixture will light first. In particular, the barium nitrate will heat to high enough temperatures to ignite the metal powder, such as iron. This gives a sparkler its name for the usual orange and white sparks. All this is awesome but none of this would happen without something to hold the constituents together. The binder of starch and water keeps everything tidy and ready for your sparkling display. If desired, other chemicals can be added to the mixture for the addition of color, similar to fireworks1, 2.
Scanning the Spark
Using microCT imaging, the chemical composition comes to light, even before the sparkler is burned. The first image (Figure 1) shows the sparkler tip before it is burned. Notice the bright specs throughout sparkler. Our hypothesis was that is the metal powder distributed in the matrix of the fuel, oxidizer, and binder. Since the goal of a sparkler is to get the temperature high enough to ignite the metal, these should in theory burst out and cause the sparks. To test the hypothesis we did what a scientist would do, burn it and see what happens.

sparkler_8um_3D  Sparkler_8um_axial

Figure 1. Image of sparkler before burning
After burning and scanning the results were quite impressive (Figure 2). All the same scan settings were used as the unburned sparkler to ensure an adequate comparison. The results supported our hypothesis as the white specs had burned up in the process leaving nothing but the charred fuel and binder with various cavities. These likely being where the metal powder had exploded out of the sparkler.

spent_sparkler_3D  spent_sparkler_axial

Figure 2. Image of sparkler after burning
We hope you enjoyed our celebration of a sparkler and we wish you great 4th of July. As always, be safe with any fireworks or sparklers and make sure to follow all handling instructions.
Did this spark your idea for an image of the month? If so, feel free to contact us at 610-366-7103 or email: brandon@microphotonics.com to submit your image of the month idea. We would love to highlight your work!

Works Cited

1. Brain, Marshall. (2000, June 30). How Fireworks Work. HowStuffWorks.com. Retrieved from http://science.howstuffworks.com/innovation/everyday-innovations/fireworks.htm.
2. How Does a Sparkler Work? (2009, December 23). Audio blog post. BASF. Canada. Retrieved from http://www.basf.ca/group/corporate/ca/en/news-and-media-relations/podcasts/chemical-reporter/sparkler.
3. Karen. (2014, June 30). Bits and Tidbits about Sparklers. CountyFairs USA. Retrieved from https://www.countyfairsusa.net/bits-tidbits-sparklers/.

Related Products

Related Articles

US Partner Form

    Coming Soon:

    Customer access to tips and instructional videos, method notes, tutorials, application notes, and other content to support your research.


    Service Engineer opening for Micro-CT Systems

    We are looking for a service engineer to join our team of experts in helping advance research by providing technical support and maintenance for micro-CT systems across the United States.

    Please submit resumes to: info@microphotonics.com

    Micro Photonics Inc.
    1550 Pond Road, STE 110
    Allentown, PA 18104



    WVC Annual Conference

    Las Vegas, NV
    February 19-21
    Booth 1484

    Privacy Policy

    What information do we collect? We collect information from you when you register on our site, place an order, subscribe to our newsletter or fill out a form. When ordering or registering on our site, as appropriate, you may be asked to enter your: name, e-mail address, mailing address, phone number or credit card information. You may, however, visit our site anonymously.
    What do we use your information for? Any of the information we collect from you may be used in one of the following ways:

    ; To personalize your experience (your information helps us to better respond to your individual needs).

    ; To improve customer service (your information helps us to more effectively respond to your customer service requests and support needs).

    ; To process transactions. Your information, whether public or private, will not be sold, exchanged, transferred, or given to any other company for any reason whatsoever, without your consent, other than for the express purpose of delivering the purchased product or service requested.

    ; To send periodic emails .The email address you provide for order processing, will only be used to send you information and updates pertaining to your order.Note: If at any time you would like to unsubscribe from receiving future emails, we include detailed unsubscribe instructions at the bottom of each email.

    Terms and Conditions

    Terms of Service for www.microphotonics.com

    Introduction. Welcome to www.microphotonics.com. This website is owned and operated by Micro Photonics Inc. By visiting our website and accessing the information, resources, services, products, and tools we provide, you understand and agree to accept and adhere to the following terms and conditions as stated in this policy (hereafter referred to as ‘User Agreement’), along with the terms and conditions as stated in our Privacy Policy (please refer to the Privacy Policy section below for more information).

    This agreement is in effect as of October 25, 2018.

    We reserve the right to change this User Agreement from time to time without notice. You acknowledge and agree that it is your responsibility to review this User Agreement periodically to familiarize yourself with any modifications. Your continued use of this site after such modifications will constitute acknowledgment and agreement of the modified terms and conditions.

    Responsible Use and Conduct. By visiting our website and accessing the information, resources, services, products, and tools we provide for you, either directly or indirectly (hereafter referred to as ‘Resources’), you agree to use these Resources only for the purposes intended as permitted by (a) the terms of this User Agreement, (b) the terms of any applicable confidentiality, non-disclosure, or other agreement between you and a third party, and (c) applicable laws, regulations and generally accepted online practices or guidelines.

    Call Now Button