• two ziploc bags, one containing flour and vinegar, the other containing baking soda and vinegar
  • ziplock bag filled with baking soda and a small cup of vinegar

Acid Rain


This investigation considers physical and chemical changes in the context of acid rain. Students examine a flour and vinegar mixture and a baking soda and vinegar mixture, making predictions, observations and explanations regarding the changes they observe. The implications of physical and chemical changes for buildings and plants are then discussed.

Example Handout

  • Grades 4-8
  • Basic familiarity with physical and chemical changes is required.
  • In person and virtual visit options available.
  • For virtual visits, the teacher and/or students will have to supply the materials.


  • Flour
  • Vinegar
  • Baking Soda
  • Ziplock bag (2)
  • Small paper cup (2)
  • Teaspoon 
  • Measuring Beaker

Follow Up and Resources

This can be an effective launch point to dig deeper into physical and chemical changes. Check out the following: 

  • Extend the investigation to include mixing different solids and liquids, for example sugar and vinegar or baking soda and water.

  • Our chemical reactions investigation: Don’t Overreact.


Changes in Matter

  • SC.4.P.9.1: Identify some familiar changes in materials that result in other materials with different characteristics, such as decaying animal or plant matter, burning, rusting, and cooking.
  • SC.8.P.9.2: Differentiate between physical changes and chemical changes.

Earth Structures

  • SC.6.E.6.1: Describe and give examples of ways in which Earth's surface is built up and torn down by physical and chemical weathering, erosion, and deposition.

  • SC.7.E.6.6: Identify the impact that humans have had on Earth, such as deforestation, urbanization, desertification, erosion, air and water quality, changing the flow of water.

The Practice of Science

  • SC.4.N.1.4: Attempt reasonable answers to scientific questions and cite evidence in support.

The Role of Theories, Laws, Hypotheses and Models

  • SC.3.N.3.2: Recognize that scientists use models to help understand and explain how things work.
  • SC.6.N.3.4: Identify the role of models in the context of the sixth grade science benchmarks.
  • SC.7.N.3.2: Identify the benefits and limitations of the use of scientific models.