Shilpa from Indiana
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Hi Shilpa,
What a great 4th of July question!
There are many kinds of fireworks. They range from simple sparklers to really complicated displays in the sky. We have all seen firework displays during the 4th of July (US Independence Day!), after a baseball game, or (my favorite) at Disney Parks.
So how do fireworks work?
Let’s think about what is required of fireworks.
Dr. Dave’s Fireworks To-Do List!
1. Mix chemicals and load into firework shell.
2. Launch firework shell up into the sky.
3. Explode and make a cool nighttime display.
How can we do that?
Chemicals and explosions!
To launch fireworks into the sky we need a mortar tube and some black powder (also known as gunpowder).
You can think of a mortar tube as a cannon (think pirates!). First the gunpowder is placed inside the tube – the people who make fireworks call this the “lifting stage” – and then the fireworks shell fits right on top!
Below is a picture of mortar tubes.
What is a firework shell?
This is the part that has the chemicals which explode and make different colors. The following is a picture of firework shells from www.howstuffworks.com. I think they look like brown apples. Click the picture for a closer look:
Once the firework shell is in the air, it needs to explode (to spread the chemicals). This is done by using a special piece of string, called a “fuse.” The fuse is attached to a big firecracker, called a “bursting charge.” Surrounding the firecracker is more black powder (the stuff that causes the BOOM!) and small bundles of chemicals, called “stars”, that give off colors when they burn.
Here is a very nice illustration showing the insides of a firework shell from www.howstuffworks.com. Click to enlarge!
Let’s imagine what happens from start-to-finish for one firework.
The firework is placed on top of lifting charge (black powder) inside a mortar tube. Firework shells are placed inside the tubes and are aimed in the right direction.
The lifting charge is ignited (by a match or an electric spark) causing an explosion that launches the firework shells into the sky. This also lights the fuse for the shell.
Eventually, the fuse will reach the firecracker inside and the shell will explode. This makes the black powder around it explode and throws out the burning packs of chemicals making a nice design in the sky!
Interesting Facts!
Sometimes small rocket motors are used. These rockets burn black powder. There many kinds of rockets, from home built models to NASA’s Space Shuttle!
Chemicals are often added to the firework so it leaves a trail of sparkles as it flies up into the night sky. Check out the picture below!
Depending on how the firework is packed, it can make different shapes in the sky. Also, did you know that different chemicals makes different colors of fireworks? Check out the picture below!
Pretty cool!
Now you know the basics of fireworks.
For a more detailed description click this link.
Enjoy!
Dr. Dave
