As earlier stated, this integrated language arts and science unit will create the needed foundation for the students to explore other types of microorganisms and for students to be able to use the scientific method as they present and follow through with an experiment related to this unit.
Appendix B lists the most important standards that this unit covers in the areas of science, social studies, and language arts. It will be observed from the list that not all the standards are specific to the seventh grade (in which this unit will be implemented). Suffice to say that most curriculums should be recursive and spiraling in complexity and breadth. It is for this reason, that some of the science standards that the unit targets will be new to students (i.e. science standard 7.4.a-Various microbes compete with humans for the same sources of food) and detailed instruction required; others, will have been introduced in prior years and can be used as springboards (i.e. science standard 6.1.b-Materials can be classified as pure substances or mixtures, depending on their chemical and physical properties); others yet are here included because they closely align to the content of this unit and with modifications the activities could be implemented in those grade levels (i.e. science standard 2.4.b-People eat different foods in order to satisfy nutritional needs for carbohydrates, proteins and fats).
Given that this is an integrated unit, I include social studies and language arts standards that are aligned with the content at hand.
A critical thinking pedagogy: Moving past the lecture
It is not the first time that when talking to a middle or high school teacher we hear their complaints that by the time our students get to them, they have lost all sense of inquiry and self-discovery. That all students want is for someone to tell them what to do, how to do it, and what to say.
This curricular unit looks at ways that we can create activities that will engage all learners and provide teachers and students with activities that reflect both effective teaching strategies and meaningful student tasks around the ways that microorganisms assist us in preparing, processing, and digesting food.
One way of introducing and engaging students is via some overarching open-ended questions. At times, these questions will drive the small anticipatory group discussions to the unit (the hook of the lesson) or to the sample activities here proposed. As such, these questions become the essential questions that we will continue to revisit throughout the unit. In other instances, these questions are posed as a means to activate prior knowledge and set an environment where enquiry and collaboration are highly encouraged and expected. The following is the guiding question to this unit:
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How do we use microorganisms to make food? (i.e. what do cheese, yogurt ,
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ginger ale. and bread have in common?)
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Due to the fact that my work requires that I take into account the needs of English language learners (ELLs) at all times, and that I look for ways of engaging classroom teachers in meaningful discussions with and among students around content area topics, these lessons are to be representative of both effective strategies as well as meaningful to the lives of the students.
Science misconceptions
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All microorganisms are harmful to humans.
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When something is fermented it has gone bad.
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Essential vocabulary
Fungi, yeast, mold, culture, fermentation, release, carbon dioxide, substrate
Outline of suggested sequence of instructional activities
The organization and layout of this unit attempts to be to a student what a cookbook is to the chef. The unit will progress, as a good meal does, through different courses from appetizers, to dessert. The appetizers become the building blocks, or the chemistry principles that will assist the learner to understand the importance that chemistry has. In the case of this unit, we start by looking at elements and compounds in terms of the ingredients in a recipe. That is, at the macro level, and as a way of contextualizing the chemistry building blocks of atoms into molecules, into elements, into chemical compounds, this will be illustrated with the ingredients needed in making pancakes. The basic elements we use are water, yeast, and flour. After these elements are combined they create a compound. At the micro level look at the makeup of each separate element: flour, water, and yeast. Here we study the composition of each ingredient separately.
However, before we can start with a menu, we must ensure that we know who is coming to the meal, or in other words, who are guests are.
Activity #1 - A meal - Introducing the unit
As a means of generating interest in the unit, I will send a note home with the students (please see appendix A) that will serve two separate purposes. First, it will provide the parents with a general description of the unit and second, the letter will serve as a parental permission slip asking for their collaboration in making their child's favorite dish. Most importantly, this letter requests information about any food allergy that will impede their child's full participation in all the activities in the unit.
Given that we are going to be working with live microorganisms, especially fungi, I recommend using an indoor mushroom patch (http://www.fungi.com/kits/indoor.html) to illustrate how mushrooms and yeast are members of the same fungi family. They are relatively inexpensive, easy to maintain, and if purchased well in advance, a great way to begin talking about microorganisms.
Activity #2 - Let's have a potluck party!- Students Sharing
This activity is great to implement early in the year for multiple reasons. It is a way of involving students and their families. Just make sure that you have responses in writing from all the parents so that you are aware of any food allergies or other food concerns. By doing this well in advance, from the beginning of the activity you will be able to ensure everyone's participation.
To begin, the teacher introduces the main goals of the unit and lets students know that throughout the unit they will learn about microorganisms, how to make soda pop, cook the most incredible pancakes, waffles, and other delicious foods using beneficial microorganisms, and that they are going to design and implement the winning science project.
As in a lab experiment, each recipe has a procedure that was followed from start to end that anyone could follow and get similar results. These steps are necessary if anyone wants to replicate the dish. The main point to get across by the completion of the activity is that the ingredients and instructions are to a recipe what materials and procedure are to an experiment.
The teacher models for the students the procedure that students will follow in presenting to their classmates the dish they brought, and copies of the recipe. The teacher orally will describe the name of the dish and the process that they followed. Given that one of the follow up lessons has to do with physical and chemical changes, the teacher will in context integrate such comments throughout the presentation. i.e. making the salad, although all the ingredients were cut into smaller pieces, and the salad dressing was homemade, the changes are physical.
As the teacher is re-telling the steps or procedure involved, he creates a list highlighting the task elements of what the presenter needs to do. i.e. First, name the dish. Second, pass a copy of the recipes to all the students (or direct them to the page where it can be found). Then, give two reasons as to why it is their favorite dish. After, list the steps needed to make the recipe (instructions). Finally, make a suggestion on how to improve the recipe.
Once the teacher has modeled the procedure to follow, in small groups the students present orally, which is their favorite dish. Even though they might not have cooked it themselves, each student will read or describe the steps in the making of the dish by following the outline of the steps created by the teacher.
Once the meal is over, the teacher will create a KWL+ chart. This graphic organizer will build on the students' prior knowledge on what they know (K) about foods, and their questions of what they want to know (W). The following questions might drive the discussion:
What do the dishes that we shared have in common? How are they different? Did any of the dishes contain any live microorganisms? What are some of the changes that took place? How did those changes take place? How is the leftover food changing? What about the food that we ate? Are these chemical or physical changes?
The teacher charts students' responses under what they (L)earned, (K)now, or (W)ant to know. Additionally (+), the teacher draws lines or creates other graphic organizers to show connections between each of the parts of what students (K)now, (W)ant to know, and (L)earned.
We will make use of this KWL+ chart as a review board listing all of the activities students have participated in; as a reflecting tool to answer the questions, did the activities help us to answer a question that we had? What did we learn from the activity? How did it help us understand? In reviewing and making connections, the teacher draws lines or creates another graphic organizer to show connections between each of the parts of what students (K)now, (W)ant to know, and (L)earned. This is the + of the KWL+.
Thus, this KWL+ is our departing point, a roadmap of where we are going, a journal of where we have been, and the end point of our lessons.
Starters or Appetizers
In a fancy meal, the appetizer places the role of getting the juices flowing in order to begin the digestion process. At the same time, it serves as a way to appeal to the person's taste to what is yet to come.
In the classroom this can be seen as the warm up before the lesson is to begin. It represents the activation of ideas and of prior knowledge that begins to generate thinking. Although, this part of the lesson is important for all our students, it is essential for second language learners. Often times this part of the lesson comes in many forms, in activating prior knowledge we can use a graphic organizer or do a brainstorm; we can create an anticipatory guide of the material that is going to be covered, or we can do a three minute individual write up about what students think of when they talk about food. This can then be shared in pairs and later presented to the whole class.
The idea here is to not only activate prior knowledge, and assess how much students know about the topic, but to wet their appetite in order to engage them in the content and in the activities that are to come. This is the first step in the learning cycle. I propose to start reviewing the previous day's KWL+ chart. This is an effective means of generating some discussion as prior knowledge is activated through small group conversation, at the same time that will serve as a "classroom memoir" of where we are, where we are going, and where we have been.
Activity # 3 - Chemical versus physical changes
In order for students to be able to understand the difference between a chemical and a physical change, students create a 3 by 5 inch card with the words chemical change on one side, and physical change on the other. The teacher proceeds to tell the following story to which students will respond when prompted as to whether it is a physical or chemical change, by raising their card with their answer. If possible, this activity is done in real time so that students can observe the changes taking place.
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First I measure and combine in a bowl 1.5 cup of flour, 2 tablespoons
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of granulated sugar, 2 teaspoons of baking power, and 1/2 teaspoon of
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baking soda. Is this a physical or chemical change?
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In a separate bowl, I blend an egg, and 1 1/3
cups of
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plain nonfat yogurt? Is this a physical or chemical change?
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I add the blended liquid ingredients into the dry mixture and mix
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them well. Is this a physical or chemical change?
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After the griddle is hot, I add 1/2 cup of the mixture to it. I let if cook
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until I see the bubbles and the batter is dry on the edges. I flip it with a
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spatula and let it cook on the other side. Is this a physical or chemical
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change?
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I put it in a plate and eat the pancake. Is this a physical or chemical change?
At each of the pauses, when students are prompted to respond by showing the card, the students turn and talk with the person next to them and give their reason as to why they think it is a physical or chemical change that it took place. When the story is completed the students, in pairs, create a definition of what a chemical and a physical change is providing samples from this or other recipe.
Finally, each group shares with the rest of the class their definition and the rationale with examples from the cooking exercise.
Activity # 4 - Main Course
The main goal of this activity is to informally present to students, through active participation, the elements of the scientific method. In order to do so, students are encouraged to do some hands-on exploration.
In the exploration phase students actively explore with the concepts of the unit without direct instruction from the teacher. Here students modify the ingredients of the basic pancake recipe used for the chemical versus physical changes activity with the objective of coming up with the "best" pancake recipe. Students must give their recipe a unique name. The role of the teacher in this phase is to expand the students' thinking process by posing open ended questions and directing students to come up with their own hypothesis, answers, and questions. Some key questions include: What do you observe happening when…? What is your thinking about why…? How could you investigate…? How could you communicate that….? What are some of the changes that you would make…? What questions do you still have…? Why did you….?
As a class we will create a rubric of what we mean by "best" pancake recipe and rate each of the pancakes batches. This rubric should be created prior to the cooking and tasting and it is best done in small groups, before coming up with a class rubric. The following is an example of a data table and rubric created as part of this activity.
Each recipe characteristic is rated from 0 "not at all" to 5 "very much".
In the next phase of the task, once students have had opportunities to explore with the concepts and content, the teacher explains and goes over formal concepts and clarifies misunderstandings or questions. In the case of this activity, we come up with the elements of the scientific method (what are we investigating or which is the problem?; making observations based on real data and coming up with hypothesis or explanations of how one property affects another; create a "fair and valid" experiment that allows us to test one variable at a time; conduct the experiment as designed; collect and analyze data, draw conclusions and present results).
Lab 1. What's for breakfast? Brewer's sugar fungus is for breakfast.
Saccharomyces cerevisae, Brewers yeast, is a living microorganism and as such, careful attention needs to be placed when working with it. When mixing yeast, special attention to temperature is a must. If the water is too hot, the reaction will be to become overactive, but soon it will soon wear out and die. If the temperature of the water is too cool, the reaction is insufficiently active, and rising will be considerably slow. At the right temperature (95 F - 105 F), lukewarm, this living microorganism releases carbon dioxide as it reacts with the sugar or gluten from the flour. It is the liberation of the carbon dioxide as the fermentation takes place that produces mini bubbles that stretch the dough and make it rise. In a sense, the texture of bread is millions of these gas bubbles, each in its own house of dough.
There are different types of flours; each characterized by the different amount of proteins that they have. Some of these proteins create gluten, which with the liquid and kneading develops and becomes the substrate for the yeast. A substrate is the organic material that the microbe uses to get its food from. In the case of yeast, the substrate is either the glucose from the sugar, or from the flour. As soon as the yeast comes into contact with the glucose, the fermentation process begins.
The gluten is what gives the texture, elasticity and volume to the bread or other flour/grain-based recipe. The gluten is the framework or scaffold that will trap the carbon dioxide bubbles created in the process of leavening. The higher the gluten content is, the greater the volume that the bread will have.
Students should be able to come up with these conclusions on their own through experimentation or through making use of the student resources at the end of this unit. The following are some of the multiple research questions or problems that can lead to experimenting with live microorganisms.
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Does the type of flour increase or decrease yeast activity? (Whole flour, all
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purpose, enriched, buckwheat, spelt, etc)
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How much sugar should we add to the batter to reach the maximum yeast
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activity?
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How does the type of flour affect yeast activity?
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What is the effect of temperature on yeast activity?
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What is the effect of sugar on yeast activity?
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What is the effect of yeast on pancakes?
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What effect do chemical leavening agents have on pancakes?
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As an extension, we will be making our own sourdough starter using some of the yeast batter and without yeast so that we can at a later time compare and contrast to other leavening agents. Our guiding question will be what is the best medium for the sourdough bacteria to grow?
Cause and Effect Connecting Words organizer
The purpose of this activity is internalize and use the knowledge that the students have acquired throughout the unit and use it as a means of rehearsing and using connecting words in writing and orally in conversation. Note the parallelism between hypothesis testing and the cause and effect exercise. For example, the cause is to the independent variable what the effect is to the dependent variable. i.e. the more food the more that the yeast grows. The independent variable, or cause (food), has a direct effect on the variable of interest, in this case growth of the yeast.
This activity can also be used as a demonstration class. The teacher can combine the ingredients and then discuss which is the cause and which is the effect with the rest of the class. Additionally, this lesson will engage the students into thinking about carbonated water and will serve as a launch pad to the next activity where students will explore and create their own ginger ales using yeast. Thus, students will be able to explore the similarities and differences between carbonated water, carbonated soda, and ginger ale.
As I stated earlier it is important that these activities integrate all the modalities of language at the same time that both the linguistic and academic needs are taken into account at all times. Additionally, it makes use of ESL strategies that will enhance use and comprehension of the language. This follow-up activity demonstrates how to integrate all modalities.
After the demonstration lesson, the teacher creates as many groups of four students as possible. Each student (in every group) is numbered from 1 through 4. Then, the teacher creates groups of "experts" by calling all the number one students to one group, all the number two students to another group, all the number threes to another group, and all the number four students to the last group. In each group they will become "experts" on the essay that they read. All the number one students read the essay What is the difference between soda and carbonated water (http://tutorials.carbonatedseltzerwater.com/category/carbonated-and-distilled/carbonated-water/). Number two students read Carbonated Drinks (http://tutorials.carbonatedseltzerwater.com/category/carbonated-and-distilled/carbonated-beverage/). Number three students read Making carbonated water (http://tutorials.carbonatedseltzerwater.com/category/carbonated-and-distilled/carbonated-soda/). The last group reads Where can you buy seltzer water? (http://tutorials.carbonatedseltzerwater.com/category/flavored-seltzer-soda-sparkling/)
After each student has finished reading their assigned section, as a group, students discuss their findings on what they read and take notes of the main idea, a couple of supporting facts, and some samples. Finally, each student (now an expert in the topic to be presented) goes back to their original group and shares what he or she learned about carbonation. In the follow up activities, students will be able to make connections between the principles involved in water carbonation and making pancakes using chemical leavening agents or microorganisms.
With the use of the KWL+ chart (see previous lesson), the teacher models how to use/create a Cause and Effect T-Chart. Model how students will use a T-Chart to keep track of the events in following a recipe or in one of the model lessons focusing on cause (why did it happen) and effect (what happened). On the left column, students write the cause and in the right column the effect. i.e. You add baking power to the lemonade. The lemonade fizzles and turns into pop lemonade.
Students then make use of the T-chart to create sentences using different connecting words. After students write sentences using cause and effect connecting words, they read them to a partner and sequence them chronologically according to the steps on the recipe. Students can make use of the following connecting words:
because, so, consequently, therefore, due to the fact, since, as a result, the reason for, thus, nevertheless
Example:
I added baking soda to lemonade. Consequently, the lemonade turns into pop.
Due to the fact that I added baking soda to lemonade, it turned into pop.
I added baking soda to the lemonade. As a result, the lemonade turned into pop.
Students will use the content from the reading about carbonation, as well as the findings from the pancake experiment, to create a cause and effect T-chart. Students will also be able to experiment with baking soda, syrup, lemons and water to experiment hands on creating their own carbonated drink.
Lab 2. What's to drink? Which is the best ginger ale we can make?
Once students have had an opportunity to create a carbonated drink using lemonade, in this activity they explore making their own ginger ale using yeast. This lesson follows the same guidelines and sequence as the previous activity.
Prior to students receiving a basic recipe for ginger ale, they are provided with portions of Chapter 1, Root Beers in American History (Cresswell, 1998). Here students read about carbonated drinks and its history. Students read about health-giving waters, the birth of the soda fountain, from corks to caps, the legacy of prohibition, root beer, and a section on self-sufficiency. The reading can be done as a jig-saw, like in the previous activity, or assigned to the group as a whole and then discussed. Each group has to come up with a main idea and supporting details for each of the sub headings of the text.
Stephen Cresswell (1998) includes many recipes for root beer (p.32), ginger ale (p.33) and pop. Any of those recipes are simple enough to be used as a basic recipe that students can experiment with as they learn about the chemical reactions taking place in the conversion of sugar into carbon dioxide. However, I like the soda pop recipe provided by LearningHerbs.com (http://www.familyherbalremedies.com/how_to_make_soda.html).
This basic recipe calls for 2 to 3 ounces of fresh ginger, 3 tablespoons of lemon juice and 3 tablespoons of orange juice, ¾ cups of sugar, 4 ½ quarts of water, bread or ale yeast and some soda bottles. This recipe will make 8, 16 ounce bottles. Given that students will be experimenting in creating the perfect ginger ale, I recommend that the quantities be cut in half until a "winning" recipe is found. Close attention needs to be placed to the amount of yeast that is added. A very small amount goes a long way!
The following research questions or problems can lead to experimenting with yeast.
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Does water sugar increase or decrease yeast activity?
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How much sugar should we add to the water to reach maximum "pop"?
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How does the type of sugar affect yeast activity?
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What is the effect of temperature on yeast activity?
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What is the effect of sugar/juice on yeast activity?
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How is the effect of chemical leavening agents different to microorganisms?
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The following tables can serve as a means of tracking different recipes in each group, or as a class.
Last word and extension activities - dessert
The need of all students to engage with hands-on experiences cannot be overemphasized enough. This is specially so in the case of English Language Learners, who through these types of concrete activities are able to integrate both language and content as they rehearse new and already known language structures.
The KWL+ chart is the logical point to give closure to this unit. As a guiding map, the KWL+ is a working chart of where we were at the beginning of this unit, and a look as to where we are in our exploration of the most important microorganisms used in cooking.
The following is a list of additional extension activities for each of the curriculum areas:
Language arts: Compare and contrast Matrix: Similarities and differences between yeast, molds, and bacteria (this can also be used as a post-assessment). Students write a persuasive essay and make and oral presentation about the benefits of microorganisms to our society.
Social Studies: Locate the names of the countries where the following specialty foods based on lactic acid fermentation are consumed: Korea (kimchi), Russia (kefir), Egypt (laban rayab and laban zeer - fermented milks) and kishk (fermented milk and cereal mixture), Nigeria (gari-fermented cassava), South Africa (magou - fermented maize porridge), Thailand (nham - fermented fresh pork), Philipphines (balao balao - fermented rice and shrimp mixture).
Mathematics: Graph consumption of cheese, bread, kefir, miso, and other foods made with the use of yeast, molds, or other bacteria.
