Wednesday, April 2, 2014

Pancakes

Today in first grade students made pancakes to add to their recipe books. Yesterday they wrote the ingredients to the recipe down to practice their handwriting as well as their fractions and capital and lower case letters. Students put a "T" for tablespoon and a "t" for teaspoon. Today, as they were reading the ingredients and telling their teacher which to put in next, they reviewed these notations and got a chance to see what the different measurements they are. Students noticed that there is a big difference in the size of the tablespoon and teaspoon as well as one cup, half cup, and quarter cup. They were reminded that to be good scientists they needed to measure accurately and follow the directions.

Once they had all the dry ingredients in the bowl, they mixed them up and made a well for the wet ingredients. The reviewed the terms solid and liquid and determined which ingredients fell into these categories. Once all the batter was mixed up the students made a prediction of what they thought would happen when they went onto the griddle. Some students predicted that bubbles would form with a gas inside!


Students moved to the griddle in back where a small pancake was placed on the griddle for each of them and they had the option of putting white or milk chocolate chips on top as well. Students looked closely for the presence of bubbles and made guesses about what kind of gas it might be inside. When the cooking was complete they were able to eat their creations and glue the directions of how to make the batter to their recipe.



Upon surveying the students while they watched their pancakes cook, most thought that this was a change that was permanent and they would not be able to return it to flour, sugar, milk, etc. One student said that it was all mixed together and so it couldn't be unmixed while another student used the evidence of heat being added and bubbles forming to explain why it can't be reversed. Thursday, they will go through all the recipes and talk about if what they made can be reversed or not.

Although the melting of the chocolate chips and the cooling back into a solid is a reversible change, the cooking of the pancake is not reversible. The reason this is not reversible is due to a few chemical reactions going on in the pancakes. First, when the dry ingredients are mixed with the wet ingredients, the proteins glutenin and gliadin combine to form gluten, this is why you shouldn't over mix your pancakes or they will become rubbery. Gluten does a great job of making a stretchy web within the pancake batter that will be able to catch bubbles during the cooking process and make your pancakes fluffy. Here is chef Alton Brown explaining how gluten forms during his bread episode Dr. Strangeloaf.

Next, most recipes call for baking powder. The reason is that baking powder is a mixture of baking soda (a base) and cream of tartar, calcium acid phosphate, or sodium aluminum sulphate, which are acids. When moistened, the acid and base react giving off carbon dioxide gas which are the bubbles that rise in the batter and leaves behind the holes that make the pancakes fluffy. Here is a great article and activity from Scientific American on what makes "Fluffy Pancakes."

The last reaction is what turns your cakes golden brown and gives off the sweet smelling aroma that attracts us to the kitchen, it is called the Maillard Reaction. This reactions takes place between the sugars and the amino acids in the proteins and goes through several rounds of chemical reactions to produce small quantities of hundreds of different flavors and colors, which is why seared meat doesn't look or taste the same pancakes. Here is a nice article and video from NPR that explains it further: 100 Years Ago, Maillard Taught Us Why Our Food Tastes Better Cooked

Click here for some fun facts about pancakes from Los Alamos National Laboratory.

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