Sandwich Bag Blasts {Learning About Acids and Bases}

IMG_0127Today marked our first project, as we experiment our way through the summer. We hope you’re joining us!

If you’re spending your summer with science, let us know on social media or in the comments section here. We’d love to hear about other families’ experimental summers!

These sandwich bag blasts were our version of celebratory fireworks this afternoon. Lucy (daughter #2) is currently in utero and there were concerns about her cerebellum development at our anatomy scan. Today, our MFM specialist gave her a clean bill of health and released us back to my regular OB-GYN. It’s a major weight off of our shoulders, so we were thrilled to celebrate the news with some backyard explosions! BANG BOOM POP HOORAY! BABY LUCY IS OKAY!

 

Sandwich Bag Blasts

Materials:

  • Zip lock sandwich bag
  • Paper towel
  • Baking soda (1-1/2 tbsp)
  • Vinegar (1/2 cup)
  • Warm water (1/4 cup)

 

Procedure:

  1. Check your sandwich bag for holes. If it’s not water-tight, you won’t get that magnificent BANG that young scientists crave. You can check it by filling it with water and shaking it around to spot leaks – or just rely on your eyesight to identify any holes.
  2. Rip your paper towel into a 6″ square (roughly, into quarters).
  3. Pour 1-1/2 tbsp of baking soda into the middle of one paper towel square.
  4. Fold up the paper towel, so the baking soda is safely nestled inside a pocket.
  5. Add the 1/2 c of vinegar and 1/4 c of warm water to the sandwich bag.
  6. Quickly, add the paper towel pocket into the sandwich bag and seal it. Emphasis on quickly.
  7. Shake, shake, shake your bag to get the reaction really going.
  8. Set down your sandwich bag, step back, and watch it swell, before BANG! The bag pops and you can call yourself the Sandwich Bag Bomb Squad.

 

 

The Science:

Almost all liquids can be qualified as either an acid or a base. Acids produce more hydrogen  (H+) ions when added to water, which deems them more acidic. Meanwhile, bases produce more hydroxide (OH-) when added to water, which deems them more, you guessed it, basic. You can thank chemist Svante Arrhenius for this classification system!

Acids (the ones with more hydrogen ions) have a sour taste and can even dissolve other materials (we call that “corrosive”). In fact, the word acid is derived from the Latin word acidus, which means “sour”. The best example of an acid is our own stomach acid, that helps us break down the foods we eat.

Bases (the ones with more hydroxide ions) can have a bitter taste and tend to be on the more slimy (think: icky) side. We also call bases “alkali” because they are “alkaline” (not acidic). An example of a base would be soap – the soap we wash our bodies with and even laundry or dish soap!

Acids-and-Alkalis-The-pH-ScaleAll of these liquids have a place within the pH scale, which ranges from 0-14. Strong acids make up the lower part of the scale (0-4), while strong bases make up the higher part of the scale (10-14). In the middle of the pH scale is 7, which is “neutral” and is neither acidic or basic. The best example of a neutral is water

Both very acidic and very basic liquids can be equally dangerous, so it’s best to work with items within the middle of the PH scale when we do experiments like this! Professional chemists use those strong acids and bases to create big reactions in chemistry labs, so if you like explosions and reactions, you might have found your future major or career!

In this particular experiment, the vinegar (acid) and baking soda (base) cause a chemical reaction that produces carbon dioxide. That carbon dioxide fills the bag and, after running out of room to continue expanding, pops the bag open with our thrilling BANG!

 

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