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Baking Soda in Cookies

This phenomenon examines how baking soda impacts the baking of chocolate chip cookies, specifically the leavening of the cookies. It compares cookies that followed the recipe exactly to cookies that did not have baking soda in them. Through observations, students will see that the cookies without baking soda do not expand the way the original cookies do. Instead, the dough will be more dense and only partially baked after the same amount of time. Students in Iowa are very familiar with chocolate chip cookies, the process and the results of baking them. This provides students with a connection to others outside of their community because chocolate chip cookies are common among many children around the country.

Sioux Center, Iowa

Driving Question


  • How does baking soda affect the way a cookie bakes?

Probing Questions

  • What happens to the final product when you substitute ingredients?
  • What happens to the final product when the quantity of baking soda  is changed?

Classroom Suggestions

  • Students can change the quantities of baking soda in the cookies and record observations.
  • Students can substitute baking powder for baking soda to see if there are any noticeable changes in the cookies.
  • The teacher can connect this phenomenon to density because baking soda primarily causes a noticeable change to density of the cookies.

Relevant Related Resources

Chocolate Chip Cookie Recipe | All Recipes: This is the website that we used for the recipe of the chocolate chip cookies.
Baking Soda vs. Baking Powder | NCSU: This website was the jumping point for our phenomenon. This site looks at how baking soda and baking powder differ in baking. We used this to help us look more in depth at what baking soda actually does.​​​​​​​
What Does Baking Soda Do in Cookies? | 20th Century Cafe: This article describes the reactions baking soda causes in cookies, and it explains the purpose for having baking soda in a cookie recipe.

Iowa Core Alignment


Conduct an investigation to determine whether the mixing of two or more substances results in new substances

Credit Info

Phenomena submitted by Kayla Vande Zande and Caroline Van't Land

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