Backyard Science: Firework science

It's that time of the year when the children are out having fun in the sun. While they're outside, encourage them to explore one of the best science classrooms -- their own backyard. Here's an experiment perfect for the Fourth of July. You can learn all about the science behind the vivid colors fireworks create by using a few items from around the house.

Materials

* Copper sulfate

* Morton's salt substitute

* Calcium chloride

* Borax

* Salt

* Boric acid

* Cotton balls

* Rubbing alcohol (70 percent isopropyl)

* Grill lighter

* Muffin pan

* Tongs

Instructions

STEP 1: Place two tablespoons of copper sulfate, Morton salt substitute, calcium chloride, borax, salt and boric acid each in a different section of the muffin pan.

STEP 2: Dip six cotton balls in the rubbing alcohol.

STEP 3: Using the tongs, pick up the cotton balls and place each in a different section. Make sure that each cotton ball is covered with the powder in each section of the muffin pan.

STEP 4: Using the grill lighter, ignite the cotton balls one at a time.

Explanation

The color of each flame depends on the ingredient being burned. Borax will burn green, salt contains sodium and will burn yellow, Morton salt substitute contains potassium chloride and burns purple, and calcium chloride will burn an orange-red. Therefore, fireworks get their colors due to the ingredient added to the firework.

Jason Lindsey is a Science Outreach Educator with Hooked on Science. Check out his website "Hooked On Science" at hookedonscience.org for webcasts and experiments that might get you hooked on science. Send him your science questions at jlindsey@hookedonscience.org. More science experiments can be found at www.semissourian.com.