Candy Lab #1 – Acidic Properties

acidic properties homeschool science experiment

Homeschool science experiments at home are so much easier thanks to candy! There are so many kitchen table labs that the kids can do just with leftover candy. Economical, fun, and versatile, hang on to that leftover Halloween candy and use it for science!

Here are a few easy-to-do labs that use candy to teach some basic chemistry concepts.

Testing for Acids

Kids know that candy can be sweet, but candy can also be sour, and that sourness often comes from a natural product called citric acid, or some other food-grade acid. In this simple lab, the kids can test for the presence of an acid by using ingredients found around the house. In this lab, the kids will taste some of the candies. I’m always conflicted about this because generally one of the lab rules is “no eating or drinking!” Explain to the kids that this is a special situation where they are allowed to taste some of the candies (where directed), but in general there’s no eating or drinking of lab materials! This is one of the major homeschool science lab safety rules.

Materials

  • A variety of sweet and sour hard candies (think Skittles, sour gummies, SweetTarts, etc.)
  • Water
  • Baking soda
  • Dixie cups
  • Plastic spoons for stirring

Talk to the kids about acids. Ask them what an acid is; how do they know when something is acidic? Acids can have a lot of different properties, depending on their molecular structure. Some common properties include: taste sour when eaten, can sting when touched, strong acids will corrode, and acids can conduct electricity.

Give the kids a sweet candy and a sour candy and ask them to hypothesize which candy is acidic! Time to see if they’re right!

Procedure

  1. Fill the Dixie cup (or another similar cup) about 1/4 of the way full with water.
  2. Add a candy.
  3. Add a spoonful of baking soda to the cup and observe.
  4. If bubbles form, then there are acidic properties in the candy. The more bubbles, the greater the acidic content!
  5. Repeat this process with another candy.
  6. Ask the kids for their conclusion: was their hypothesis correct? Which candy has acidic properties?

The Science

Just like in your science fair volcano, the baking soda will react in the presence of an acid to create fizzing. This fizzing is evidence of a chemical change, and carbon dioxide gas is being produced.

There are actually two steps occurring in this reaction. The first is when the diluted acid reacts with the baking soda (sodium bicarbonate) to form sodium acetate and carbonic acid. However, carbonic acid is unstable and a decomposition reaction occurs, producing carbon dioxide gas. The gas is released as bubbles. Interestingly, the carbon dioxide gas is heavier than air, so it’ll collect near the bottom of the cup, just above the level of the water. There are more fun experiments you can do to prove that there’s carbon dioxide there, even though you can’t see it.

Experiment

Let the kids play around with different candies. Always ask them to hypothesize first, guessing which candies will have acidic properties and which won’t. Other ideas for this lab include:

  • make a graph showing which candies react with the baking soda and which don’t
  • change the amount of baking soda used – this can be measurement practice
  • change the amount of water or the water temperature to see if that has an effect on the reaction

Clean Up

Liquids can be put safely down the drain. Recycle plastic and paper cups where possible, and throw away or compose any candy solids left behind.

 

 

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