If your child already tried making an antacid or baking soda rocket, she’s probably raring to to more science experiments that use chemical reactions to make thing pop.
The Exploding Sandwich Bag Science Experiment puts on a great show and uses the same acid-base reaction that makes quick bread rise when it bakes.
This experiment is a perfect way to show your child that sometimes you can combine household products to create an explosive reaction without putting anyone in danger. That doesn’t mean it’s messy, though. You’ll want to make sure to do this experiment outside or “explode” the sandwich bag in the bathtub or a large plastic tote.
What Your Child Will Learn (or Practice)
- Scientific inquiry
- Acid-base reactions
- The Scientific Method
- Sandwich size Ziploc bags
- Paper towels
- A pair of scissors
- A ruler
- Measuring cup and spoons
- Baking soda
- Warm water
The Exploding Sandwich Bag Science Experiment
- Help your child find a sandwich bag that doesn’t leak. Sometimes even right out of the box, the seams of a bag will let water through, and a watertight Ziploc is critical to the experiment. It’s easy enough to check for leaks--just fill a sandwich bag about halfway with water, zip it up, turn it upside down, and shake it around. Set aside a few of the non-leaky bags.
- Give your child a piece of paper, a pencil and a ruler. Ask her to measure and draw a 5-inch by 5-inch square. Once you've double checked her measurements, she can cut out the square.
- Place the paper towel square on a flat surface. Measure and place 1 ½ TB of baking in the middle of the paper towel.
- Show your child how to fold the paper towel into a small packet. Fold the top third over the mound of baking soda, then fold the bottom third up over. Next fold each side into the middle. It will make a small square, which is the timed-release "explosive" packet. Set it to the side.
- Help your child measure ½ cup of vinegar and hold the sandwich bag open while she pours in the vinegar. Keep holding the bag while she measures and adds 1/4 cup of warm water.
- Warning: This step requires some fast moving! Zip up the sandwich bag about halfway across the top. Stuff the timed-release packet inside the bag while your child zips up the rest of the bag super quick.
- Ensure the bag is completely closed and then shake it a little bit. Put it in your designated safe zone, stand back and watch as the sandwich bag expands and explodes!
Follow-up Questions to Ask Your Child:
- Why didn’t the sandwich bag explode immediately?
- Do you think the outcome would have been different if we used a different size bag? What would have happened with a snack-size bag? A quart bag? A gallon bag?
- Would the same thing have happened if we used just water and baking soda?
- What would happen if we used just vinegar and baking soda?
- How would the outcome change if we used tissue paper or construction paper instead paper towel?
What’s Going On
As the paper towel dissolves the baking soda mixes with the vinegar-water solution. Vinegar is an acid and baking soda is a base, which means together they create a chemical reaction called an acid-base reaction. This reaction creates carbon dioxide gas.
The gas takes up more room than the sandwich bag has available so it keeps filling the bag until there isn't any more room. The pressure of the gas building up pops the seams and tops of the bag with a loud and visible explosion.