Finding a 
better milk 

Author: Shane McMaster

This resource was developed as a result of participation 
in CSIRO’s teacher professional learning program, 
Teacher Researcher in Partnership Program.

© Finding a Better Milk (created by Shane McMaster) 
(2018). Copyright owned by Queensland Department 
of Education. Except as otherwise noted, this work is 
licenced under the Creative Commons Attribution 4.0 
International Licence. To view a copy of this licence, visit
http://creativecommons.org/licenses/by/4.0/

CSIRO Australia’s National Science Agency



Finding a better milk

Scientific processes in a real-world context

The TRiPP project that I undertook involved 3 days working at the CSIRO lab at QLD Biosciences Precinct 
St Lucia with Dr Simone Osborne. The project centred around food futures and the search for a better 
natural milk to use for infant/baby formula. The project involved simulation on gastric and intestinal 
digestion and then testing the digesta for the degree of digestion, toxicity on intestinal cell lines and 
inflammation response. Within this project I was able to work with advanced equipment in a specialist 
lab environment, conducting relevant and cutting-edge research. Equipment like PC2 fume hoods, culture 
incubators and robotic autosamplers which normally aren’t available in schools was able to be used and 
explored. I also had the opportunity to work with another teacher who was on the project, which was a 
great addition to my experience, working collaboratively. 

The project was very valuable and refreshed, for me, the idea of linking science to real-world contexts to 
make it more relevant and exciting. The procedures we undertook, and the labs within which we undertook 
them are much higher level than what can be achieved in a high school context, however. In order to bring 
the TRiPP experience back to the classroom I took inspiration in the use of the scientific method to solve 
real-world problems, as well as adapting the experiment to a more classroom-friendly method.

Nature of the problem

In keeping with the original research aims of the TRiPP project, the problem given to students will be based 
around researching milk alternatives. Their aim will be to experiment on Cow, Goat and Soy milk to establish 
which is the most easily digested. The intention is to take a small part of the research into milk in the future that 
could be realistically achieved in a year 8 science lab.

Students will extend on their knowledge of the digestive system and chemical changes in this project. As well 
as this they will be exposed to new content around enzymes, protein structures and chemical indicators. 
Students will also develop their science inquiry skills as they learn to apply the scientific method to the context 
of food biochemistry. They will be exposed to equipment and techniques that they haven’t used before such as; 
pipettes, water baths, indicators and volumetric flasks, as well as accurately producing diluted samples and the 
use of controls. Given the level of the students though, the task was scaffolded so that all students conducted 
the same experiment, though it was open-ended in terms of the end results.

Suitable year levels and subject area

This investigation has been designed to be used with year 8 students, though could easily be used with 
years 9 and 10 as well. It only addresses the science discipline of STEAM directly, however students can 
incorporate technology aspects in their reflection. It will pull directly from existing science content 
knowledge as well as address students’ use of the scientific process.

It is being considered that this experiment is adapted to suit a year 12 chemistry unit on food and biochemistry. 
In that case it will be more open-ended and require students to design most parts of the experiment and to 
more thoroughly explain the results and their potential implications.



Curriculum links

Biological Sciences

Multi-cellular organisms contain systems of organs carrying out specialised functions that enable them to 
survive and reproduce (ACSSU150)

Chemical Sciences

Chemical change involves substances reacting to form new substances (ACSSU225)

Science Inquiry Skills

• Collaboratively and individually plan and conduct a range of investigation types, including fieldwork and 
experiments, ensuring safety and ethical guidelines are followed (ACSIS140)

• Measure and control variables, select equipment appropriate to the task and collect data with accuracy 
(ACSIS141)

• Summarise data, from students’ own investigations and secondary sources, and use scientific 
understanding to identify relationships and draw conclusions based on evidence (ACSIS145)

• Communicate ideas, findings and evidence-based solutions to problems using scientific language, and 
representations, using digital technologies as appropriate (ACSIS148)

Learning objectives

Through this project students will complete the following leaning objectives:

• Students will learn to use Biuret indicator to analyse protein content

• Students will learn how to dilute samples for analysis

• Students will learn how enzymes work in protein digestion

• Students will learn how to take accurate measurements using pipettes

Students learning outcomes

By the end of this project it is expected that students will:

• Understand that different milks are digested differently

• Understand how to conduct an experiment based on real-world contexts

• Be able to evaluate experiments to identify its validity and accuracy

• Understand how studying food could support the health of future populations

Format and assessment

The format of this unit will be as a week-long classroom investigation. Students will have to complete a 
scaffolded experimental report template as they plan, conduct and analyse the investigation. The experiment 
will be conducted in groups, with the report being independent. The report is a formative assessment and will 
be assessed via a criteria sheet at the back of the template. Students will be required to self-assess and then 
participate in class discussions about the experiment and their efforts.

ICT

No ICT opportunities are foreseen with this project.



Finding a better milk

Investigation

Context and background

Milk and dairy products have been used for human nutrition long before agriculture was developed. Milk is 
defined as “an opaque white fluid rich in fat and protein, secreted by female mammals for the nourishment 
of their young”. It is used by all mammals, though humans were the first to use the milk of another animal 
to feed their young. Baby formula is used by mothers who cannot, or choose not to, feed their young with 
their own milk. Dairy based baby formula is currently made almost exclusively from cow’s milk. 

Alongside these social issues of the use cow’s milk, some biological concerns have been raised regarding 
the consumption of cow’s milk. In particular, some evidence suggests that cow’s milk is not easily digested 
and in fact causes inflammation, an irritation to the intestines, as it is digested. This can be a particularly 
important issue when looking at the developing guts of babies. 

Milks are composed of three main biological components: Sugars, fats (lipids) and proteins. These are 
digested as they move through the digestive system by enzymes (biological catalysts).

Proteins are made up of long chains of amino acids connected together by peptide bonds. When they are 
digested, they are broken down into chunks that are only two amino acids long and eventually single amino 
acids. Different proteins will be broken down differently however. How easily they are broken down plays a 
big role in how much nutrition can be obtained from them and also whether they irritate the intestines. 

Aim

To determine which milk is most easily digested. Cow’s milk, Goat’s milk and Soy milk will be provided for 
testing. Given that this will be undertaken in a junior science laboratory this investigation will be used to make 
some preliminary conclusions and determine if further study is needed.

What is the independent variable for this experiment?



Risk management

HAZARDRISKMANAGEMENT
Biuret indicator and Irritation and poisoningProtease enzymefrom spills or ingestion

Broken glassCuts and abrasions from 
broken glass

Chemical wastesEnvironmentalcontamination risks

Method background

The Biuret test is a simple test that is used to detect proteins. It uses a blue 
solution of copper sulfate and sodium hydroxide which turns purple when 
a chain of three or more amino acids is present. The copper sulfate reacts 
with the peptide bonds between the amino acids and turns purple. The 
more proteins that are present, the darker the darker the shade of purple. 
Pink indicates a medium amount of proteins. If no proteins are present, the 
solution with be blue. Therefore, the colour can be used to estimate the 
concentration of proteins

This experiment will use protease enzyme, an enzyme that breaks down 
proteins, and a water bath set to 37°C to simulate the body’s digestive 
conditions. The samples will ‘digest’ for 30 min in the water bath 
before being tested.

What is the dependent variable for this experiment?

Example of Biuret test 
colour range

Source: http://brilliantbiologystudent.
weebly.com/biuret-test-for-protein.html


Describe how the dependent variable is going to be measured.


Equipment and materials

• Samples of cow’s, goat’s and soy milk
• 3x 100ml volumetric flask
• 3x 10ml pipette
• Distilled water
• Biuret indicator
• Protease enzyme
• Water bath
• 6x medium test tubes
• Test tube rack
• Permanent marker
• 1x Disposable 1ml pipettes


Sample preparation

For this investigation you will be using a 5% solution of each milk.

1. Label three 100ml volumetric flasks. One each with cow’s, goat’s and soy

2. Use the pipettes to take a 5ml sample Cow’s milk and place it into the labelled volumetric flask. Fill the flask 
up to the line with distilled water and place the stopper on top.

3. Gently invert the flask three times to mix.

4. Repeat steps 2 and 3 for Goat’s and Soy milk.

Protein determination method

1. Label one medium test tube “Undigested cow’s” and another “Digested cow’s”.

2. Using the pipette place 10ml of the prepared Cow’s milk solution into each test tube.

3. Repeat steps 1 and 2 for the remaining milks.

4. Place 1ml of protease enzyme into the “digested” test tubes using the disposable pipette.

5. Place the three “digested” test tubes into the water bath and leave for 15 minutes.

6. After 15 minutes, remove the test tubes from the water bath. Add one squirt of Biuret indicator to each of the 
“undigested” and “digested” test tubes. Gently shake to mix and record observations of colour after 1 minute.

Results

OBSERVED COLOUR

MILK TYPE

UNDIGESTED

DIGESTED

Cow

Goat

Soy





Observations



Analysis of results

Using your results and observations explain which milk, if any, is most easily digested.

Discussion

1. Are these results qualitative or quantitative? How would this affect the reliability of the results?

2. Do the result you obtained match with other groups? Why/Why not?

3. Was your experiment a fair test? Explain your response.

4. What could be done to increase the reliability of this experiment? Suggest two changes that could make the 
experiment more reliable/fair.

Conclusion

Which milk would be best to use in baby formula in the future? Is it possible to make a responsible decision 
from these results? Was the aim successfully fulfilled? How could this investigation be extended using these 
results? (Answer in full sentences and paragraphs)



Self-assessment

Mark yourself honestly based on how you feel you did

ASSESSABLE 
ELEMENTS

DESCRIPTORS

A

B

C

D

E

OVERALL

THE STUDENT WORK DEMONSTRATES EVIDENCE OF:

Planning and 
conducting

Planning of 
investigations that: 

• identify and describe how 
variables are changed, 
measured and controlled 

Accurate collection of 
reliable data 

Planning of 
investigations that: 

• identify and describe how 
variables are changed, 
measured and controlled 

Accurate collection of data 

Planning of investigations 
that: 

• identify variables to 
be changed, measured 
and controlled 

Partial planning of 
investigations that: 

• identify variables to 
be changed, measured 
and controlled 

Use of provided 
investigations methods 

Processing and 
analysing data 
and information 
and evaluating

Use of these patterns and 
trends when explaining 
relationships to justify 
conclusions

Use of these patterns and 
trends when describing 
relationships when justifying 
conclusions 

Use of these patterns and 
trends when justifying 
conclusions 

Drawing of conclusions 

Statements about data

Evaluating

Evaluation of the quality of 
data to justify the explanation 
of how effective modifications 
to methods could improve the 
quality of their data 

Explanation of how effective 
modifications to methods 
could improve the quality 
of their data 

Explanation of how 
modifications to methods 
could improve the quality 
of their data 

Description of modifications 
to methods 

Statements about 
modifications

Communicating

Concise and coherent use of 
appropriate language and 
accurate representations to 
communicate science ideas, 
methods and findings in a 
range of text types 

Coherent use of appropriate 
language and accurate 
representations to 
communicate science ideas, 
methods and findings in 
a range of text types 

Use of appropriate language 
and representations to 
communicate science ideas, 
methods and findings in a 
range of text types 

Use of everyday language 
and representations to 
communicate science ideas, 
methods and findings 

Fragmented use of language 
and representations to 
communicate science ideas, 
methods and findings