Exploding lunch bags!
ACES Activity of the week: Participants: 8 kids and 3 parents.
Pop...pop...pop...exploded the ziploc bags with vinegar and baking soda (and little food coloring for more fun).
Exploding lunch bags was the first of the three experiments we did today to learn about the reaction between sodium bicarbonate (baking soda) and acetic acid (vinegar)...a classic acid-base reaction.
Demo: I wrapped a tablespoon of baking soda in paper towel and dropped it in a ziploc bag pre-filled with a cup of vinegar and quickly sealed it. Wrapping baking soda in paper towel was necessary to slow the reaction. Slow fizz developed into rapid bubbles and ziploc bag started filling up and it became so big that it exploded! See video below.
Each participant made their own exploding lunch bags! Air was charged with anticipation of explosion. Some bags popped fast, some slow and some didn't...causing animated discussion as to why the variance - too much ingredients or too little. When asked what is causing the fizz and bubbles...almost everyone answered unanimously..."some gas is being released"...leading us to the next experiment...blowing a balloon up with the gas released.
So, we put some vinegar in the bottle, added baking soda and quickly put a balloon over the opening and watched the balloon inflate! So, yes, fizz means gas is being released. But what gas is being released...? This led us to the next experiment.
We lit a candle and poured the gas over the flame...and lo and behold...it put out the flame!!! So what could it be? Something that is non-flammable and definitely non-poisonous (otherwise the experiment wouldn't have been allowed)...and somewhere along the way someone shouted out...CO2!!!! Yes...it is carbon-dioxide!
Finally we ended the day by briefly studying the chemical equation:
NaHCO3 (baking soda) + HC2H3O2 (vinegar) → NaC2H3O2 (sodium acetate) + H2O (water) + CO2 (carbon dioxide)