Lesson 7 of 12
Objective: SWBAT define density, describe how it can be changed through a chemical reaction, and apply the concept of density to the process of cooking pancakes.
I start the lesson and spark the students' interest by playing the Minion Pancake Art video:
Students relate to it not only because they are familiar with the movie, "Despicable Me" and the cute little minions, but also because we have been studying the science behind breakfast foods for the last several days. Based on the short video introduction, most of them have already been able to guess that today is Pancake Day!
I ask the students to guess what food we may be learning about today, to which all of them will quickly respond, "Pancakes"! Next, I ask if any of them have ever stopped to think about the science behind these fluffy breakfast treats. Most will anticipate this question, especially if you have conducted any of the former lessons in this unit. And even if they haven't stopped to think about it before, I can assure you that many have contemplated this concept within the last 5 minutes. I introduce today's topic, explaining to the students that we will learn today how to make the fluffiest, most delicious pancakes, thanks to... wait for it... SCIENCE (of course)!
To introduce the main scientific concept behind today's lesson, I start by having the students look up the definition of gluten from Wikipedia. I then review and describe the formation and molecular composition of gluten, providing a diagram to help the students visualize what gluten looks like in its natural form.
After students have an understanding of the composition, structure, and uses of gluten, I ask them to predict what they think will happen to gluten when it is combined with a leavening agent, such as baking soda. I have them refer to the diagram, which describes the process that takes place, and have them draw what they envision when they picture this process occurring.
I have the students take turns sharing their drawings with the people at their table group, comparing their ideas and asking clarifying questions to understand the thought processes of their peers.
Now that we have grasped a basic understanding of the chemical reactions that take place, I pass out the Pancake Handout* and have students partner read, highlighting the connections between starches and density. After reading and highlighting, I ask them to compose a one sentence description of how cooking pancakes demonstrates chemical reaction that is related to a change in density.
I have each set of partners share their statement aloud. I purposely select students with a stronger understanding to share first, which allows the students with weaker connections to revise their statements before sharing. As each group reads, the class provides feedback to help each other revise their understanding of diffusion as necessary.
*The information presented in this handout was adapted from the blog, “The Science of Food”, by Scott McQuery.
Now that students have gotten a solid grasp of the concept of diffusion and how it relates to cooking, it's time to make some pancakes!
*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 spread them across 4-5 stations around the room. Each station is equipped with the items listed on the The Scientific Secret of Fluffy Pancakes handout.
Each student group gets the opportunity to mix three samples of batter and create 1-2 pancakes from each sample. Once they have made their pancakes and collected data about each type of batter, they get the pleasure of eating their science lab!
This lesson is different than the other food chemistry lessons because it incorporates testing of different recipes, determining which provides the desired outcome and then explaining why. The video gives you important information needed to guide students through this investigation, because it is possible for students to never arrive at their destination without some prompting.
While eating, each group discusses their findings together and compares the batters to the pancakes they produced. They then compose a group summary of their findings, which must include the following ideas:
- A description of each batter and the pancakes that resulted, including size, taste and texture.
- A description of which pancake was most well-liked by the group, accompanied by reasons why this was considered to be the "best".
- A description of which pancake was least preferred by the group, accompanied by reasons why this was considered to be the "worst".
- A description of how the preparation process led to the results of each pancake's size, taste and texture.
- Cooking suggestions for others about how to make the fluffiest, most desirable pancake.
As an additional or alternative assessment, students complete the Pancake Questions Exit Ticket as homework or 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 scenarios.