EXPERIMENT. Exploring acidity with potions in the kitchen.

kitchen-acids_acidity-experiment

Food Science for kids! Help your young scientist explore acids and bases during this simple experiment you can do on the kitchen counter. Click “print” in the upper right corner to print the lesson.

Kitchen Potions: Experimenting With Acids and Bases

  • Time: 5-10 minutes
  • Difficulty: easy
  • Print

Explore the acidity of common kitchen ingredients with this fun lesson.

Question:

What is an acid?

Explore the acidity of different food ingredients in your kitchen.

Background:

Acids and bases are at the foundation of food science. When a food scientist makes a new food product, the acidity of that product is important for many reasons.  A product with higher acidity can maintain a longer shelf life (last longer) than a product with less acidity. However, a product with high acidity usually tastes more sour than a product with less. A food scientist is expected to develop a product that tastes good, and is safe and stable over time.

What is an acid? How do we determine if a food is more or less acidic than another food?

ph-scale

The pH scale is what food scientists use to determine the acidity of a food. The pH scale ranges from 1-14, where a pH of 7 is considered “neutral.” A higher pH indicates the item is more basic, and a lower pH indicates the item is more acidic.

Experiment:

Materials needed:

  • White Vinegar
  • Baking Soda
  • Different liquid kitchen ingredients: water, lemon juice, milk, soda, fruit juice, buttermilk, honey, etc. (Note: Bleach is included on this pH scale for reference only. Do not experiment with bleach.)
  • Pipettes
  • Clear containers for mixing. Clean, clear, empty soda bottles or jars work great.
  • Baking sheet, or dish (to catch the mess!)
  • Food Coloring (if desired)

Procedure:

  1. Set up your station! Place empty bottles and jars on the baking sheet.
  2. Add a few tablespoons of baking soda to one container and set aside. Add white vinegar to another container (if using, mix in food coloring of your choice), and set aside. Use the pipettes to add a little vinegar to the baking soda. Explain to your scientist that baking soda is a basic ingredient, and vinegar is an acidic ingredient. Show them where each ingredient falls on the pH scale. Note the reaction that occurs. 
  3. When finished with the vinegar, clean out the baking soda/vinegar mixture and begin again. Add more baking soda to the the container and set aside. Add different kitchen ingredients of your choice to the other containers and set aside.
  4. Begin experimenting! Use the pipettes to add each liquid to the container with baking soda. Encourage your scientist to experiment with different amounts. Show your scientist where each ingredient falls on the pH scale. Note how each ingredient reacts differently with the baking soda. 

Observations:

  • What happened when vinegar was added to the container with baking soda?
  • What other kitchen experiments did you experiment with? What happened when these ingredients were added to baking soda?
  • Which liquids created the strongest reactions with the baking soda?

Discuss with your scientist what they see, hear, smell, etc. All observations are important!

Conclusions:

  • Why did different ingredients react differently?

Review what was learned during the experiment. Discuss with your scientist how the baking soda (a basic ingredient), reacted with the vinegar (an acidic ingredient). Discuss how the ingredients with a lower pH (and stronger acidity) create stronger reactions with the baking soda than the ingredients with a more neutral pH.

copyright Food Science Secrets

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