Each Fourth of July, people across the U.S. watch colorful fireworks displays. The tradition dates back to 1777, during the Revolutionary War. Ships shot guns over Boston Harbor to celebrate the Colonies’ independence.
Fireworks are fueled by gunpowder. When the powder is lit, it explodes. Chemical pellets burst, releasing colorful sparks into the air. Different chemical combinations can release sparks in every color of the rainbow.
Fireworks displays are beautiful, but they have downsides. They can cause injuries. Fireworks also produce pollution and make noises that can scare animals and harm people’s hearing.
That’s why experts are working to develop safer and quieter fireworks. “Our goal is to make fireworks that are better for the environment without changing how great the show is,” says chemical engineer Eric Johnson.