STEAM WEEK: Simple Experiments at Home

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Experiment #1: Exploding Lunch Bag

YOU WILL NEED:

  • One small zip-lock bag
  • Baking soda
  • Warm water
  • Vinegar
  • Measuring cup
  • Tissue

DIRECTIONS:

  • Put 1/4 cup of warm water into the bag.
  • Add 1/2 cup of vinegar to the water in the bag.
  • Wrap the baking soda up in the tissue by folding the tissue around it.
  • You will have to work fast now – partially zip the bag closed, but leave enough space to add the baking soda packet. Put the tissue with the baking soda into the bag and quickly zip the bag completely closed.
  • Gently place the bag on the ground and step back! The bag will start to expand and if all goes well…POP!

HOW DOES IT WORK:

Nothing like a little chemistry to add fun to your day. What happens inside the bag is pretty interesting. The baking soda and vinegar eventually mix. When your ingredients mix, you create an ACID-BASE reaction and the two chemicals work together to create a gas, (carbon-dioxide – the stuff we breathe out). Well, it turns out gasses need a lot of room and the carbon dioxide starts to fill the bag, and keeps filling until the bag can no longer hold it anymore, POP!

EXTRA EXPERIMENTS:

  • Will different temperatures of water affect how fast the bag inflates?
  • What amount of baking soda creates the best reaction?
  • Which size bag creates the fastest pop?

Experiment courtesy of Science Bob

Experiment #2: Erupting Rainbow/Color Explosion

YOU WILL NEED:

  • 6 small plastic containers
  • Food coloring (mix to create secondary colors of the rainbow)
  • White vinegar (diluted solution containing acetic acid CH3COOH and water H2O )
  • Baking soda (sodium bicarbonate –NaHCO3)
  • An easy to clean hard surface – We used a clear plastic tray

DIRECTIONS:

  • Put food coloring in the bottom of a small plastic container.
  • Fill each container half way with white vinegar.
  • When ready, drop 1 to 2 teaspoons of baking soda into each container.
  • Step back and watch the color explosion.

HOW DOES IT WORK:

Much like the Exploding Lunch Bag Experiment, the combination of the white vinegar and baking soda causes a chemical reaction because one is a base (baking soda) and the other is an acid (white vinegar).

The vinegar and baking soda reaction is actually two separate reactions.

  • The first reaction is the acid-base reaction. When vinegar and baking soda are first mixed together, the hydrogen ions in the vinegar react with the sodium and bicarbonate ions in the baking soda. The result is two new chemicals: carbonic acid and sodium acetate.
  • The second reaction is a decomposition reaction. The carbonic acid formed as a result of the first reaction immediately begins to decompose into water and carbon dioxide gas. The carbon dioxide gas creates the bubbles and foam that you see.

EXTRA EXPERIMENTS:

  • Use chilled white vinegar instead of room temperature vinegar.
  • Pour the colored vinegar into cups containing 1-2 teaspoons of baking soda.
  • Try using water and an antacid tablet instead of vinegar and baking soda.

Experiment #3: Mentos Geyser

YOU WILL NEED:

  • 2 liter of diet soda (we used Diet Coke)
  • 1 package of Mentos
  • 1 piece of paper – will be rolled into tube
  • Tape
  • Safety Goggles

DIRECTIONS:

  • Using your sheet of paper, create tube to hold your Mentos.
  • In the middle of a large field or your backyard, position your bottle of soda so that it will not fall over.
  • Carefully open your bottle of diet soda.
  • Load 7 Mentos into your paper tube.
  • Make sure you are wearing your safety googles – drop your Mentos into the bottle of diet soda and RUN!

HOW DOES IT WORK:

The bubbles in the soda are made of a gas called carbon dioxide. It makes the soda fizzy.

The surface of the Mentos is not as smooth as it seems. If you were to look at the Mentos through a microscope, you would see that the surface is full of dents, scratches and bumps.

The carbon dioxide molecules collect on these rough spots and form bubbles which rise to the surface. All those Mentos in a lot of soda make a lot of bubbles that rise to the surface and push the soda out in a fountain.

Here is a link to the American Chemical Society’s version of this experiment with an explanation.

EXTRA EXPERIMENTS:

  • Do any other types of candy cause an eruption?
  • Try cold diet soda vs. warm diet soda.
  • Does it have to be diet soda or do regular (sugary) sodas work?
  • Try crushed Mentos.