How to Make a CO2 Sandwich Explore the pop factor of vinegar and baking soda. email to friend
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1. Tear off a square of toilet paper.
2. Twist or fold the toilet paper around the pile of baking soda making a small packet.
3. It’s best to have someone help you with the next few steps. Open the zipper-lock bag and measure a 1/4 cup of vinegar into the bag. Add a 1/4 cup of warm water to the bag.
4. Zip the bag closed, but not all the way. You want a small opening just large enough to sneak in the wrapped up baking soda.
5. IT'S TIME FOR A FIELD TRIP. Move the experiment to the sink, or better yet OUTSIDE! Remember, it’s all about teamwork. Drop the baking soda bundle into the bag and quickly seal the bag closed. Place the bag on the ground (or in the sink if you’re indoors) and get out of the way. Watch closely as the bag begins to puff up… it gets bigger and bigger until… BAM! Pop goes the sandwich bag.

How does it work?

Sure, bubbling liquids and popping bags are fun, but what’s the science behind the exploding lunch bag? When you mix vinegar and baking soda, a chemical reaction takes place producing a gas called carbon dioxide (CO2). If you really want to impress your friends, use the chemical names for each of the ingredients. Acetic acid (that’s vinegar) plus sodium bicarbonate (baking soda) produces carbon dioxide gas and water. The bag puffs up because the carbon dioxide gas takes up lots of space, eventually filling the bag. If there’s more gas than the bag can hold… KABOOM! If you’re lucky, the zipper-lock seal will bust open, but the bag will not break. Now you can reuse the bag to make another CO2 sandwich. Wrapping the baking soda in tissue paper is a clever way of slowing down the reaction. It takes a few seconds more for tissue paper to dissolve so that the vinegar and baking soda mix.

But Wait! There’s More…

• How does the temperature of the water affect the pop? Repeat the experiment using cold water instead of warm water.
• Try changing the amount of vinegar and baking soda you use to see how the reaction changes. Remember to only change one thing (variable at a time). For example, you can increase the amount of vinegar you use to 1/2 cup, but be sure to keep the amount of baking soda (one tablespoon) and the water (1/4 cup) the same. By changing only one variable at a time, you’ll be able to determine which ingredient has the most impact on the POP!
• Wrap the baking soda in two or three pieces of tissue. How will this affect the reaction?
• What are 3 more variables you can change?