If you want your cupcake to rise, you need to use baking soda.

Baking soda is a leavening agent. It creates air bubbles (technically, carbon dioxide) in your batter, when heated. Without it, your baked goods will not rise to the desired levels and the airy texture you're looking for will be adversely affected.

Formally known as sodium bicarbonate, it is a white crystalline powder that is naturally alkaline. Baking soda becomes activated when it's combined with both an acidic ingredient and a liquid.

Due to its unique and highly alkaline composition, baking soda can also be used for cleaning, deodorizing, beauty products, insect bite relief, natural mouthwash, putting out fires, weed killer and much more.

My controlled variables that were the same in every batch of cupcakes were: (1) the ingredients; (2) oven temperature; (3) cook time and (4) size of each cupcake. 

• Sept 1. Preheat an oven to 350 degrees F (175 degrees C). Add cupcake liners to a standard muffin tin.. Combine flour, baking soda, and salt in a bowl; set aside.
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• Step 2. Heat the butter and milk in a small saucepan over low heat until the butter has melted. Beat the sugar, eggs, egg yolk, and vanilla with an electric mixer in a large bowl until it has thickened slightly and is lighter in color. Gradually beat in the flour mixture on low speed until just incorporated. Slowly pour in the hot milk, beating until just combined.
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• Step 3. Fill ⅔ of each cupcake liner with batter.. Bake about 20 mins until toothpick inserted into center comes out clean. Cool cupcakes in pan for 10 minutes. Transfer cupcakes to a cooling rack to cool completely.

• Sept 1. Preheat an oven to 350 degrees F (175 degrees C). Add cupcake liners to a standard muffin tin.. Combine flour, baking soda, and salt in a bowl; set aside.
•  
• Step 2. Heat the butter and milk in a small saucepan over low heat until the butter has melted. Beat the sugar, eggs, egg yolk, and vanilla with an electric mixer in a large bowl until it has thickened slightly and is lighter in color. Gradually beat in the flour mixture on low speed until just incorporated. Slowly pour in the hot milk, beating until just combined.
•  
• Step 3. Fill ⅔ of each cupcake liner with batter.. Bake about 20 mins until toothpick inserted into center comes out clean. Cool cupcakes in pan for 10 minutes. Transfer cupcakes to a cooling rack to cool completely.

So … does baking soda really matter for making cupcakes? Yes, I think it does.  Baking soda is activated when it interacts with acid and a liquid, which creates air bubbles. The air bubbles help the cupcakes rise, creating the airy texture. The end result is a light and fluffy dessert that everyone will love and enjoy.

This is important to know because a lot of people don have baking soda in their house and maybe your kid needs to make something for a bake sale and you don want to go out and buy baking soda what would you do. It is important to know what you need for different ingriedients to bake. 

• Wrong measurements used for ingredients
• Using expired ingredients
• Over/under cooking cupcakes
• Over/under filling batter in cupcake liners
• Wrong type of ingredients used
• Not using cupcake liners
• Over mixing batter
• Forgetting to use an ingredient

https://www.allrecipes.com/recipe/218425/cupcake-princess-vanilla-cupcakes/

 Google      https://www.healthline.com/nutrition/baking-soda-vs-baking-powder#baking-soda

https://www.bobsredmill.com/articles/what-does-baking-soda-do#:~:text=Due%20to%20its%20unique%20and,weed%20killer%20and%20much%20more.

I would like to thank my mom and my cousins and my aunt because they helped me come up with the idea. My mom helped with the oven when baking! I also want to thank my mom for taking all the photos and helping me with some spelling.