STEM Activity: More STEM in the Kitchen — Mixtures and Solutions

Celebrate National Sandwich Day (Nov. 3) and National Pickle Day (Nov. 14) by getting creative with food! This fun activity will help you get hands-on with STEM in your kitchen by exploring the difference between chemical mixtures and solutions.

Experiment 1: Mixture for a Sandwich

Materials Needed

• Bowl, medium sized
• Bread, crackers or veggies
• Canned chicken or tuna, or tofu tuna
• Celery (optional)
• Green onion (optional)
• Mayonnaise
• Mixing spoon
• Salt and pepper to taste

Step-by-Step Instructions

1. In a medium-sized bowl, add the chicken or tuna, mayonnaise, salt and pepper, as well as celery and green onion if you’d like.
    
2. As each item is added, notice what happens to it in the bowl.
    
3. Use a mixing spoon to stir the ingredients together and notice what the ingredients look like after stirring. How are they different than when they were separate?
    
4. Spread your mixture on crackers or bread, or dip some veggies in it. Can you taste each one of the different ingredients in the mixture?

Experiment 2: Solution for Quick Pickles

Materials Needed

• 1 cup water
• 1-2 tablespoons salt
• 1/3 cup apple cider or white vinegar
• 2 tablespoons sugar (optional)
• Bowl, medium sized
• Onion or green onion, sliced
• Small cucumbers, sliced

Step-by-Step Instructions

1. In a separate medium bowl, add the sliced cucumbers, water, salt, vinegar, onion and optional sugar.
    
2. As each item is added, notice what happens to it in the bowl.
    
3. Use a mixing spoon to stir everything together and notice what the ingredients look like in the bowl once they begin to mix together. Did they change? How so?
    
4. Cover the bowl and refrigerate for 30 minutes.
    
5. Observe the bowl’s contents for any changes you can see.
    
6. Sample the quick pickles. Can you taste all the different ingredients in the solution? How is the combination of these ingredients different from those you combined for the sandwich mixture?

What Are We Discovering?

In cooking, combining different ingredients can lead to various mixtures that have distinctive properties. This is chemistry! A mixture is a combination of two or more different ingredients that when combined, retain their original properties. So, when you combine chicken, celery and mayo together, you could separate them back out again (although it might be difficult!). The ingredients are mixed together but don’t go through any chemical changes. On the other hand, when you combine water, salt, vinegar and sugar to make “quick pickles,” the ingredients undergo a chemical change as the solids dissolve into the liquid. It would require additional steps to separate the dissolved solids back out of the liquid. When solids dissolve into a liquid, we call it a solution.

For more chemistry fun, check out fantastic National Inventors Hall of Fame^® Inductee chemists like Margaret Wu, inventor of synthetic lubricants. She sees her kitchen as another laboratory where she can experiment. Her work in chemistry is used in many applications from passenger car engines to industrial wind turbines. Learn more about her incredible story by visiting our website.

Keep the Fun and Learning Going!

For more hands-on STEM fun for your family, visit our blog.