Expanding Yeast

In a Reggio-inspired environment, provocations are used as a starting point to encourage interest, involvement, risk, creativity, and sustained shared thinking among the children.  We want to offer them the opportunity to explore and discuss thoughts and ideas without the notion of failure and to come up with a pracitical application of their understanding of things.

In this case, yeast quickly became the focus of discussion while creating the dough for our pizzas.  The children were amazed at how the dough just seemed to expand over a matter of minutes.  They voluntarily checked on the status of our dough as it grew.  This inspired us to choose other recipes that required yeast.  The students looked on again to determine if the yeast would behave the same way.  We then agreed to bake the same item with yeast and without yeast so that children can make a comparison.  They observed a physical difference in the way that they looked and also noticed a difference in taste.

With that in mind, the teacher placed a few items on the table to provoke thought.  She gave them 3 empty bottles, three balloons, and a few measuring cups, and asked the question, “How does yeast work?”

The students recalled what they had learned with Ms. Maryam about how yeast eats “honey” and it starts to breathe air causing it to “puff up.”  “When the yeast eats the honey, it puffs up!’ Nohea and Teagan said.

As the discussion continued the question began to evolve into, what else does yeast like to eat?  Does yeast only like honey?  This evolution created an excellent opportunity to reenforce the scientific method.  Whenever children are given opportunities for hands-on learning they are more likely to remember the material as well as gain the ability to apply what they have learned in other situations.

Once the students determined the questions.  They moved to the second step in the scientific process which is to form a hypothesis.

The students discussed what types of things they like to eat and offer those as a suggestion.  “I know, we can do sugar,” Tirza said.  Teagan even suggested that we use apples.

The students suggested that we put honey in one, sugar in another, and apples in the last bottle.  The teacher reminded the students that we had to add water to the yeast.  “How much water should we use?” the teacher questioned.

“Well how much water did we use the last time?” Nohea was suggesting that we use the same amount of water as the recipe called for.

The students then started to test their hypothesis by adding water to the bottles, beginning their experiment!

The students put 2 cups of water in each bottle.  The students had to make sure that everything was same, so they could see how the one thing that was different changed the reaction.

One of our students proudly shows how much water has been added to the bottle by her classmates.

Once an equal amount of water had been added to each of the bottles, the students then began to add in the yeast.

The students all took turns passing around our yeast packets, carefully pouring equal amounts into each bottle.

They quickly stirred  the yeast into the water so that could add the items they wanted to test.  Once the correct amount of yeast was in each bottle, the students then began to add in the variables.  A variable is the item that is generally being tested.

The students began to add the three items they wanted to test:  honey, sugar, and apples.

The students then covered  each bottle with a balloon so that they could have a visual item to measure the differences.  After covering the bottles, they sat back and were amazed by the results.

The balloons began to expand.  The children noticed that some were larger than others.  Nohea measured each balloon and noted that the bottle that contained honey was the biggest.  She then realized that the bottle with apples was also big, but the bottle that contained the sugar had the smallest balloon.


The following week the students observed that the balloon with sugar deflated over the week, but the bottle that contained honey and apples sustained their gas pressure.

The students then put together a lab report explaining the scientific process they used during the yeast experiment.  They are currently working on a display board to show off the great work that they were involved in.

This activity addressed the following learning goals:


((1)  Scientific investigation and reasoning. The student conducts classroom and outdoor investigations following home and school safety procedures and uses environmentally appropriate and responsible practices. The student is expected to:

(A)  identify and demonstrate safe practices as described in the Texas Safety Standards during classroom and outdoor investigations, including wearing safety goggles, washing hands, and using materials appropriately;

(B)  discuss the importance of safe practices to keep self and others safe and healthy; and

(C)  demonstrate how to use, conserve, and dispose of natural resources and materials such as conserving water and reusing or recycling paper, plastic, and metal.

(2)  Scientific investigation and reasoning. The student develops abilities to ask questions and seek answers in classroom and outdoor investigations. The student is expected to:

(A)  ask questions about organisms, objects, and events observed in the natural world;

(B)  plan and conduct simple descriptive investigations such as ways objects move;

(C)  collect data and make observations using simple equipment such as hand lenses, primary balances, and non-standard measurement tools;

(D)  record and organize data and observations using pictures, numbers, and words; and

(E)  communicate observations with others about simple descriptive investigations.

(3)  Scientific investigation and reasoning. The student knows that information and critical thinking are used in scientific problem solving. The student is expected to:


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