Intermediate fermentation bag module

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introductory fermentation bag

Reference: https://www.glbrc.org/outreach/educational-materials/fermentation-bag

what materials are needed

Required:

  1. Dry active yeast (one 4 oz. jar contains approximately 36 teaspoons of yeast, which will make 36 bags)
  2. Warm water source
  3. Small graduated cylinders (100mL)
  4. Measuring spoons (one teaspoon for each feedstock source and the yeast to avoid cross-contamination)
  5. Feedstock(s): sugar, cornmeal, corn stover, sawdust, etc.
  6. Resealable zipper bags (“snack" size) with fill-in labels (see Supplementary Materials for label template).

Recommended:

  1. Rulers to measure bag inflation. See Supplementary Materials for instructions.
  2. Classroom-grade ethanol probe (Vernier or PASCO) or breathalyzer for detecting ethanol levels. See Supplementary Materials for instructions.
  3. 2-4 liter thermos (with spout) for dispensing warm tap water
  4. Paper towels
  5. print this data collection sheet

Pre-experiment questions

  1. What food source will you give to your yeast?

  1. What changes, if any, do you expect to observe with your bag over time?Explain.

  1. Do you expect to see any differences in observations between food sources that your class is comparing? Explain.

During experiment questions

During the experiment: Record your observations and measurements.

Yeast food source: _______________________

Start time:__________  End time:__________  Total time (min):___________

Observations & Measurements: Before After
Record scientific observations & measurements
(changes in appearance, smell, etc)

what are the steps

1. In a snack-size resealable zipper bag, combine 1 teaspoon of sugar (or another feedstock) and 1 teaspoon of yeast.

2. Add 50 mL (1/4 cup) of warm tap water (approx 40° C) and seal bag closed, removing as much air as possible.

3. Mix gently. Lay bag on a flat surface and watch for results – fastest results should be achieved in 15 minutes.**

4. Optional: Measure and compare ethanol and/or CO2 production using ethanol probes, breathalyzers, rulers, etc. Discuss and interpret results.

break point: 45 minute lesson plan

After experiment questions

After the experiment: Analyze and interpret your results.

Summarize what you know about substances in the bag before and after the experiment using this table:

Questions Start of experiment After experiment
What's in the bag?
What evidence do you have?

Propose an explanation for the changes you observed.

Compare your results with the class. What differences did you observe between food sources made of sugar, starch or cellulose?

Propose an explanation for those differences.

break point: 45 minute lesson plan

Class room variations: Guided inquiry

Reference: classroom variations

Overview: Fermentation with a Bag, Bottle and Balloon
Students work in small groups (“research teams") to investigate two guiding questions:

1.) “Which feedstock will produce the largest volume of CO2 gas?"

2.) “What methods could be used to collect data to measure volume of CO2 produced?"

Student teams are given flexibility to choose research questions, feedstock options and data collection methods. Example feedstocks could include, ripe versus unripe bananas, breakfast cereals, sugar, corn starch, sawdust, etc.

Example data collection could include measuring bag volume, time to bag inflation, balloon ininflation circumference, or Vernier CO2 gas pressure sensors.

Suggested materials

Suggested Materials and Supplies:
The suggested materials and supplies listed are necessary to provide flexibility in the inquiry lab.

Teachers may choose to limit the supplies due to time and developmental needs of students. The basic supply list includes the feedstock, containers and simple means to measure the volume/production of CO2 gas.

Classrooms with ethanol, CO2 or pressure probes may choose to use them to provide a more exact data measurement. Various solutions and the use of fruit for a feedstock are options for an extension to the lab presented here.

Instructors and students are encouraged to be creative with investigating different feedstock options, measurement techniques and the effects of different treatments.

Materials:

  1. Feedstock options: Corn starch, sugar, saw dust, snack bag sample of dierent cereals (with nutrition label), (optional): ripe & unripe banana
  2. Solution: Water, salt (optional), corn syrup (optional)
  3. Microbes: Yeast
  4. Glassware: 250ml Erlenmeyer Flasks or at bottom test tubes/round test tube, test tube holders
  5. Other: Snack size and Quart size Ziploc bags, balloons , graduated cylinders, measuring spoons,
  6. thermometers, Optional:s, rubber tubing, tape measure, gram scale.
  7. Safety: Goggles required

Procedure


The following procedure for guiding students through this investigation is presented based on the “5E Instructional Model," this procedure can easily be adapted to different instructional approaches. Learn more about this instructional model here: http://www.bscs.org/bscs-5e-instructional-model.

ENGAGE:

  1. Prior to the introduction of this lab, students are asked to bring in one small snack size baggie with a favorite cereal and a copy or cutout of the nutrition label.
  2. Upon entering the classroom, students participate in a shortened version of the traditional GLBRC lab, “Fermentation in a Bag." This was used as a “Science Starter" or warm-up activity.
  3. An overview of the unit is provided after discussing the initial Fermentation in a Bag activity.
  4. Two essential questions are asked:
  5. “Which feedstock/cereal will produce the largest volume of CO2gas?" and,
  6. “How can data/evidence be collected to measure CO2 gas?"
  7. Prior to division into “research teams" a review of materials/supplies, procedures and safety procedures is provided.
  8. In small groups, students are asked to brainstorm their own questions which could lead to an investigation. (Optional: Distribute a “ClaimsEvidence-Reasoning" sheet to structure student investigation).

EXPLORE:

  • Divided into research teams, students complete the following steps as they plan and carryout their investigation:
  • BRAINSTORM AT LEAST TEN RESEARCH QUESTIONS. SELECT ONE QUESTION TO INVESTIGATE. (Example: How does temperature affect CO2 gas production).
  • MAKE A CLAIM.
  • IDENTIFY DEPENDENT & INDEPENDENT VARIABLES.
  • DECIDE HOW TO MEASURE YOUR DEPENDENT VARIABLE.
  • DESIGN AN INVESTIGATION THAT WILL PROVIDE RICH DATA (EVIDENCE) IN A CONTROLLED EXPERIMENT.
  • CHECK WITH THE INSTRUCTOR BEFORE BEGINNING YOUR INVESTIGATION.
  • CONDUCT AN INVESTIGATION WITH A CONTROL
  • COLLECT DATA
  • DISPLAY DATA
  • PRESENT: USE DATA TO SUPPORT OR REFUTE YOUR CLAIM.

EXPLAIN:

Research teams present preliminary findings during an informal data presentation session.
Teams are asked to restate their “claim" or hypothesis, describe or prepare a data table or graph with their data and provide their reasoning for their results using the data they collected.

EXTEND:

(Optional-time permitting) Students may refine or extend their investigations
to explore new questions or collect new data with revised procedures based on what
they learned in their first investigation.

EVALUATE:

Students summarize findings across all research investigations. Teachers
may provide an exit slip or ask students to provide a brief response to questions from
the investigation.

Commentary and modifications

With the constrains of a typic science classroom, there is rarely enough time, money for supplies or capability for students to do more than surface-level investigations. In this lab, teachers may allow students to design most phases of a true investigation including how to collect data, design and standardize procedures and ask questions that lead to investigations.

Adding cereal as a feedstock to this lab added high interest for students and
provided a surprising nding. In their lab, students found that Cheerios produced more CO2 than Corn Pops. This led to a better comparison of the sugar content by weight andvolume on the cereal labels.

When time is limited, teachers may select the data collection method of choice using 9" balloons (check for latex allergies) or probes (CO2/pressure) from the lab.

To further limit time, teachers may choose to allow a group brainstorm of research questions and then select one or two from the list that all groups will investigate.