Cookie Chemistry

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Objective

SWBAT apply the processes of diffusion, density, and law of conservation to the process of baking cookies.

Big Idea

Now that we know all about the behavior of molecules and atoms, how does it relate to what grandmother does in the kitchen?

Engage

5 minutes

I like to start this lesson by activating background knowledge and sparking a little excitement. First, I project the image of cookies on the board. I set a timer for 60 seconds and have students list all the words they think of as they stare at the picture, until time is up. After 60 seconds has passed, I have each student share one word they wrote, provided no one else has already said it.

After everyone has had a chance to share, I ask them to repeat the process, except this time, only "scientific" words can be used. (I don't explain what that means to me; I let them use their own judgement.)  We repeat the process again, listing and sharing words. My hope is that the students will be able to use some of the words we have covered in prior lessons to appropriately describe the cookies. If they are unable to do this, I suggest a few words (such as molecules, atoms, solid, diffusion, etc.) and ask how these words may relate.

Explore

10 minutes

In order to learn about the science behind baking the perfect cookie, I have the students complete the TedEd Lesson, "The Chemistry of Cookies". This lesson consists of a video followed by a series of multiple choice, short answer, and extended-thinking questions. Depending on time constraints, I have students either watch the video in class or complete as a flipped homework lesson. (See my reflection for more information on flipped lessons.)

Whether this section is performed in class or at home, the students should review the video as many times as they need in order to be able to correctly answer each question and to be able to confidently discuss the material in class.

In this video I tackle show and explain a great tool to support a Flipped Classroom: 

Explain

15 minutes

Next, I pass out the Cookie Cloze handout* and have students partner read, filling in the blanks with appropriate terms and concepts that will properly illustrate the scientific processes behind baking.

After completing the handout, we compare answers as a class, as I call on random students to give their responses. The random call helps me to assess whether or not they understand the concepts and are ready to move on to the lab. Students who are not ready will work in a small group with me, re-watching the video and pausing to discuss. Once they have a clearer understanding, they can perform the cooking lab.

*The information presented in this handout was adapted from the blog, “The Science of Food”, by Scott McQuery.

Elaborate

30 minutes

Now that students have gotten a solid grasp of the chemistry behind cookie baking, it's time to bake some cookies!

*For this activity, I usually elicit the help of parent volunteers to make sure students are working safely and using proper hygiene practices.

I start by having each student wash, dry, and sanitize their hands. Then I send them to 4-5 stations around the room, each of which is equipped with the following:

  • 1 stick (1/2 cup) softened butter (salted or unsalted)
  • Light or dark brown sugar
  • 1 large egg
  • Flour
  • Chocolate chips
  • Vanilla extract (optional, for flavor only)
  • Mixing bowl
  • Large spoon for mixing
  • Measuring cups
  • Small cookie sheet
  • Toaster oven
  • Oven mitts

Each student group gets the opportunity to bake 1-2 dozen cookies.  Once they have made their treats, they get the pleasure of eating them!

Evaluate

10 minutes

I pass out the Cookie Questions Exit Ticket for students to complete before leaving for the day. This document will help me to assess their knowledge and clarify and misunderstandings they have at the beginning of the next class. It also allows me to determine if the students' understanding is clear enough to apply to other situations.