Saturday, November 15, 2003

How Do Firecrackers Work?

I am sure by this time of you most of you have seen, heard and even fired firecrackers. But, do any of you know what makes firecrackers crack, bang, and light up? If not, I will explain it to you. It is actually quite simple--it's science.

Today's firecrackers use gunpowder. But, firecrackers came long before gunpowder. The actually date centuries across to China. In fact, the firecrackers were entirely natural or organic. They were probably an accident, too. It is said that these early firecrackers came about because someone tending a fire ran short of fuel and decided to throw in a few lengths of green bamboo. Bamboo is a type of plant. The bamboo, knobby round reeds, would blacken, smoldered, and hissed. Surprisingly, they would end up exploding. How did this happen?

The answer is that inside bamboos are pockets of air and sap. These pockets, when weakened by the fire, will expand and eventually burst. The result is a sharp reverberating bang. Back then, this never-before-heard noise was quite alarming.

The Chinese figured that if this noise scared them it would scare evil spirits. One particular evil spirit was Nian. This spirit was known to eat crops and people! To protect themselves, the Chinese would use "bursting bamboo" or pao chuk at all special ceremonies such as weddings and celebrations for centuries.

Soon, a Chinese chemist accidentally discovered gunpowder. This chemist was mixing around sulfur, charcoal and potassium nitrate (KNO3) and BANG! This bang was more powerful and louder than ever!

Over time, the Chinese used chemistry to perfect their firecrackers. They also used this knowledge to do more than just scare evil spirits. They used firecrackers and extensions of them---rockets and bombs---to blow away their enemy.

Luckily, many scientists have stayed true to making firecrackers fun! These scientists have found that certain chemicals make the firecrackers colorful. And, potassium chloride (KClO3) was found to be even better than KNO3 as it made the colors deeper and brighter. Example chemicals that make certain colors are strontium to make red, barium to make green, copper to make blue, and sodium to make yellow.

Little Lion Experiment:

How to make safe firecrackers:


  • Toilet paper or paper towel rolls
  • Dry rice or dry beans
  • Colorful wrapping paper
  • Curling ribbon


Cover the cardboard rolls with wrapping paper. Leave about 3 inches of excess paper on each end. Gently twist wrapping paper to close ends. Secure the ends of the wrapping paper with ribbon. Before securing last end, put a few dried beans or rice inside. Shake the roll. It will make noise like a "firecracker."