Teaching scientific methodology

on the examples of yeast

protocols

Joanna Lilpop,

Educational Research Institute, Warsaw, Poland

Changes in the Core Curriculum in Poland

The Core Curriculum has changed in 2009.

It formulates requirements due to the knowledge on scientific

methodology, including:

designing and conducting experiments and observations,

describing conditions of the experiment,

recognition of the control probe,

conclusions formulation

Furthermore the curriculum describes certain experiments and

observations that should be done during teaching process.

The aims of research – Science Subject Section IBE

“Laboratory of Thinking - Diagnosis of Science

Education in Poland” is to provide information on the level

of scientific knowledge of secondary school (15-years old)

graduates taught according to the new curriculum.

Developing assessment tools for measuring scientific

literacy skills among students (scientific reasoning,

differentiation between facts and opinions, understanding

of popular-scientific texts etc)

Searching for and dissemination of good practices in

teaching science.

Results come from the PISA trial item: Bread dough PISA 2006

standardization test on the random probe of 219 15-years old Polish

students:

1. Students do not know what is the reason why douhg rises

2. Students have basic problems with the experiment desing and the

recognition of the controle probe.

Proposed solutions:

Practical protocols on yeast, as a good practice examples to allow

students to discover the chemistry and biology of yeast fermentation in

open-ended investigation

Assessment tools for scientific literacy to asses the evolution of

student’s knowledge and understanding

Recognized misconeptions

Fermentation causes the dough to rise.

Why does the dough rise?

A. The dough rises because alcohol is produced and turns into a gas. (11%)

B. The dough rises because of single-celled fungi reproducing in it. (44%)

C. The dough rises because a gas, carbon dioxide, is produced. (35%) ***

D. The dough rises because fermentation turns water into a vapour. (8%)

Recognized misconeption 1.

*** indicates the correct answer.

Percentage data comes from standardization test on the probe of 219

15-years old Polish students. The percentage does not sum to 100%

because of omissions and other responses.

The mass of the dough is the same

at the start of each of the four

experiments shown below.

Which two experiments should the

cook compare to test if the yeast is

the cause of the loss of mass?

A. The cook should compare experiments 1 and 2. (28%)

B. The cook should compare experiments 1 and 3. (35%)

C. The cook should compare experiments 2 and 4. (8%)

D. The cook should compare experiments 3 and 4. (28%) ***

Recognized misconeption 2.

Classroom protocols from VOLVOX project

Why does dough rise? What do fungi eat?

Each of the worksheets contains:

The story with the real life problem

Formulation of research question and hypothesis

Detailed procedure of the experiment that allows to solve

to problem

Table to collect data

Place to draw the graph

Questions to help analyze the data

Formulation of conclusion

Problem solving

Classroom protocols from VOLVOX project

Why does dough rise? What do fungi eat?

Each of the worksheets contains:

The story with the real life problem

Formulation of research question and hypothesis

Detailed procedure of the experiment that allows to solve

to problem

Table to collect data

Place to draw the graph

Questions to help analyze the data

Formulation of conclusion

Problem solving

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Why does dough rise?

Origin of the protocol: Estonian

Investigation on how temperature affects the

intensity of yeast fermentation.

Method: measuring the diameter of balloons

placed on the bottles containing yeast dough.

Bottles are incubated in different temperatures.

Quantitative data are collected. Graph may be

plotted.

Advantages: cheap and easy, takes about 30

minutes.

Further investigations: Change of the

independent variable. What gas is collected in

the balloon?

What do fungi eat?

Origin of the protocol: Estonian

Investigation on how concentration of substrates

influence the intensity of yeast fermentation.

Method: measuring the growth of yeast dough

inside the drinking straws.

Quantitative data are collected. Statistical

analysis of data may be performed. Graph may

be plotted.

Advantages: cheap and easy, takes about 40

minutes.

Further investigations: influence of other factors

on yeast fermentation?

Immobilisation of yeast in calcium alginate beads

Origin of the protocol: UK

The aims: Introduction to the techniques of cell

immobilisation, basic studies on fermentation rate.

Method: Yeast cells are immobilised on the alginate

beads and placed in the substrate solution. The

indicator coulour change is observed in the

fermentation lock.

Qualitative or quantitative data are collected.

Advantages: approach to the biotechnology,

procedure spectacular for students.

Further investigations: How immobilisation process

influence the activity of yeast cells?

Examples of assessment tools

How to assess whether students overcome

the misconception?

Assessment tools concering the yeast

investigations

Misconception 1.

– the reason why dough rises

The yeast dough rises because:

A. The yeast cells rise and become bigger (12%)

B. The yeast feed the sugar and reproduce (15%)

C. Fermentation of yeast produce CO2 that spongy the dough (58%) ***

D. Flour reacts with water and produce CO2 that spongy the dough (12%)

Standardization test on the random representative

probe of 917 15-years old Polish students in 2011.

Yeast experiment item Karol wanted to investigate what is the optimum content of sugar for rising the yeast

dough. He thought that the more sugar he adds, the better the dough will rise. To make

the investigation, he prepared dough from flour, water and yeast, and divided it into 5

equal portions. To four portions he added from one to four spoons of sugar. He filed

each of five straws with the different portion of dough to the level of 5 cm. He left those

straws standing in the room temperature. After 10 minutes he measured the level of

dough in each straw.

Straw number

I II III IV V

The quantity of sugar added (in spoons) 0 1 2 3 4

The increase of dough in the straw after

10 minutes (in mm)

6 32 46 41 38

What hypothesis has Karol verified in this experiment?

A. Sugar is not needed for dough to rise. (5%)

B. Ingredients for rising dough are: water, flour, yeast and sugar. (9%)

C. What amount of sugar is the optimum for dough to rise? (36%)

D. The more sugar is added the better the dough rises. (47%) ***

Standardization test on the random representative probe of 917 15-years old Polish students.

Experiment design Question.

Students were analyzing the experiment design and the results of

Karol’s experiment.

Which of the following conclusions is the most accurate?

A. On the basis of the results it is true that the more sugar is added

the more dough rises. (20%)

B. The results strongly deny that the more sugar is added

the more dough rises. (39%)

C. On the basis of only one probe it is impossible to say weather

the more sugar is added the better the dough rises. (39%)***

Other students think, that Karol cannot verify his hypothesis because he

failed in the experiment design. Determine if their statements are

correct.

Statements Is that correct statement?

Karol should additionally prepare the

dough without yeast and sugar.

□ Yes / □ No ***

Karol should place the straws filled with

the dough in different temperatures.

□ Yes / □ No ***

Karol should repeat his experiment

several times.

□ Yes *** / □ No

Experiment design Question – version 2.

Conclusions

Understanding of the nature of science should be a skill of

every well educated citizen of the modern world.

Refreshment of teaching methods is required including:

everyday problems and situations that are familiar to

students

hands-on practice experiments

using scientific inquiry during the teaching process

Adequate assessment tools must be used at classroom

and exams to complete the teaching process.

Where the resources can be found?

PISA Released Items – Science, OECD PISA, 2006.

http://www.oecd.org/pisa/38709385.pdf

Assessment tools by CKE

http://cke.edu.pl/images/stories/0012_Gimnazjum/100826_Informator%20gi

mnazjalny.pdf

Volvox protocols

in Polish: http://www.biocen.edu.pl/volvox

in English http://www.eurovolvox.org

in Estonian http://www.ut.ee/volvox/

„Quality and effectiveness of education - strengthening

of institutional research capabilities.”

The project is co-financed by the European Union under the European Social Fund

Educational Research Institute

Górczewska 8 Str., 01-180 Warsaw, Poland

phone.: +48 (22) 241 71 00, mail: ibe@ibe.edu.pl

Contact: j.lilpop@ibe.edu.pl