1. Teaching scientific methodology
on the examples of yeast
protocols
Joanna Lilpop,
Educational Research Institute, Warsaw, Poland

2. 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.

3. 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.

4. Recognized misconeptions
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

5. Recognized misconeption 1.
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%)
*** 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.

6. Recognized misconeption 2.
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%) ***

7. 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

8. Classroom protocols from VOLVOX project
Why does dough rise? What do fungi eat?
 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
Guided inquiry scheme
Each of the worksheets contains:

9. 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?

10. 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?

12. 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?

14. Examples of assessment tools
How to assess whether students overcome
the misconception?
Assessment tools concering the yeast
investigations

15. 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.

16. 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.

17. 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%)***

18. Experiment design Question – version 2.
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

19. 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.

20. 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/

21. Contact: j.lilpop@ibe.edu.pl
„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