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How do Chemical Leaving Agents Work?



I always struggle with making baking science concrete. So this year, I decided to take a different approach.

Remember in elementary school when everything was new, and every little thing your teacher did amazed you. High school students are just like that. 

Chemical leavening agents are nothing complicated but when you introduce them to your students they stare at you like deer looking into a head light.

So let's step out of our comfort zone of lecturing and let the students have some fun with a guided discovery approach.

Lesson starts here:

Make sure that your students understand that chemical leavening agents are man made. Below, is a video that I show my students about the history of baking and the science behind chemical leavening.


So here is a full proof way to explain to your students what chemical leavening agents actually do in a recipe.

Baking Soda Bomb!!!

What you will need:
1-? Baking soda ( the more the bigger the "explosion"
Paper towel (5inch square)
Vinegar ( the more the bigger the reaction)
Sandwich baggy (any brand)

Instructions: 
First, take your agreed upon amount of baking soda and place it in the center of the 5 inch square of paper towel. Fold the paper towel into an envelope. (This is your detonation timer)

Then, place your agreed upon amount of vinegar in the baggy.

Next, go to a place were you don't mind if somethings get wet with the vinegar.

Place the timer in the baggy and zip it up in a hurry.

Shake up the baggy, and place on the ground and stand back. 


So what's going on??

Baking soda "sodium carbonate" is alkaline and when placed in the presence of an acid it will react. 

The reaction that takes place is the creation of carbon dioxide and in regards to the experiment can be really fun:)

So in cooking: 

That is the same process of alkaline reacting with an acid is taking place when you make a chocolate chip cookies. The baking soda (alkali) in your cookie reacts with brown sugar(acid), and when these two ingredients combine you get co2 which is the gas that makes all bread products to rise. 

*Will talk about gluten later in regards to making products rise.  

Besides baking soda there is one other chemical leavening agent. 

Baking powder. 

This ingredient speeds up the process of leavening even more for a baker.

 Baking powder is baking soda mixed with an acid (like cream of tartar). So now all you need for leavening to take place is just a little bit of H20.

Chemical leaving agents are used in the production of "quick breads". 

I hope to discuss quick breads in another post.

Please let me know if this is helpful, and don't forget to share:) 

 The video of the experiment is up on twitter check it out @tz7432. 




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