Dairy Industry Curriculum Activity

Dairy Industry
Curriculum Activity

Victorian Curriculum Links

Science Understanding

Solids, liquids and gases behave in different ways and have observable properties that help to classify them (VCSSU076)

Changes to materials can be reversible, including melting, freezing, evaporating, or irreversible, including burning and rusting (VCSSU077)

Scientific understandings, discoveries and inventions are used to inform personal and community decisions and to solve problems that directly affect people’s lives (VCSSU073)

The growth and survival of living things are affected by the physical conditions of their environment (VCSSU075)

Science Inquiry Skills

With guidance, pose questions to clarify practical problems or inform a scientific investigation, and predict what the findings of an investigation might be based on previous experiences or general rules (VCSIS082)

Decide which variables should be changed, measured and controlled in fair tests and accurately observe, measure and record data (VCSIS084)

Compare data with predictions and use as evidence in developing explanations (VCSIS086)

Communicate ideas and processes using evidence to develop explanations of events and phenomena and to identify simple cause-and-effect relationships (VCSIS088)

Key Learning Intentions

Students will develop a deeper understanding of the impact of the dairy industry on the environment with increased methane gas production. They will learn how and why methane is produced and how variables affect its production. They will also learn about how biogas is being harnessed for environmental gain.

Background

Cattle are the No. 1 agricultural source of greenhouse gases worldwide. As cows eat their food ruminates in their digestive system fermenting and breaking down and releasing methane gas burps. Each year, a single cow will belch about 100kgs of methane. Methane from cattle is shorter-lived than carbon dioxide but 28 times more potent in warming the atmosphere. With over 264 million dairy cows worldwide the impact of their methane production on increasing global warming is extremely concerning.

Some scientists are considering whether changes in the diets of cows could reduce methane emissions. Recent studies have shown that feeding one type of seaweed at 3% of the diet has resulted in up to 80% reduction in methane emissions from cattle. Fats and oils show the most potential for practical application to farming systems and have shown methane emission reductions of 15–20%

Other scientists have discovered ways in which methane and other gases released when organic matter decomposes can be harnessed and repurposed for good.

When we think of a renewable energy source, the first thing that comes to mind is the sun, the wind, or even water. However, decaying food waste can become a source of renewable power. When organic matter (plant and animal residue) begins to break down or rot, two gases are created: carbon dioxide and methane. These gases are called biogas and when harnessed can become a renewable energy source.

There are many industries that have begun to harness the potential of biogas as a renewable power source and turn waste into energy. Is it possible that the damage of the dairy industry on the environment could be turned into something which could help the environment instead?

Instructions

Materials

Blender or food processor
Funnel
Kitchen Scale
8 empty 600ml plastic bottles with a line marking ¾ of the bottle.
8 balloons
Duct tape
Water
1 measuring cup
1 cup of grass
1 cup seaweed sheet
6 organic food items of students’ choice (fruits, vegetables or grains)

Tune In

https://youtu.be/WshrROiPlD0

Activity
Preparation: Organise the materials for the experiment and place these items on a separate equipment table. The teacher will demonstrate the process of setting up the experiment by blending the grass with water using the funnel to put it into the first bottle with the balloon taped to the top. This will be the control for the experiment.

Each group will need the same equipment but will select their own feed variable for their hypothetical cow. One group will need to select the seaweed sheet option but the other selections are student-directed.

During the experiment, the students will be observing how the fermentation of each different material produces biogas at different rates. Provide each student with a copy of the Student Worksheet to record their own predictions and observations. As a whole class read through the instructions (below) before beginning the experiment.

Instructions:

Divide the students into groups of three or four.

Provide each group with a bottle, a measuring cup and a balloon and allow them to select a food item.

Students need to cut their food item into small pieces and measure 1 cup. This will be blended into a puree. Water may need to be added for some food items.

Students should weigh the puree using the kitchen scale. 60 grams of the puree should be added to the water bottle and extra water added so the mix comes to the marked ¾ line. The funnel may be needed for this step.

The balloon is attached to the top of the bottle and taped in place tightly so no gas is able to escape during the observation period. The bottles are then labeled and placed next to the control bottle.

Over the course of a week, students record their observations on the Student Worksheet.

Discussion

Once you have completed your experiment, organise the students into a discussion circle and invite the students to share their observations and results as part of the discussion.

Discuss the observations students recorded on their Worksheets, including:

What did you see (observe) happening in your experiment?
How did the different variables of biogas emissions compare?
Did anything unexpected happen? If so, can you think why it may have occurred?
How did your predictions compare with your observations?
How would you change this experiment if you were to repeat it?

Break the class into pairs and assign pairs with two of the following questions to answer, ensuring that each question is answered (questions also available on the Student Worksheet):

1. What impact does methane from cows impact on our environment?

2. How does the diet of the cows impact on the amount of methane they produce?

3. What is biogas and how is it created?

4. How is biogas able to be collected and utilised in the real world?

5. Is there a way the dairy industry could harness the biogas created by cows for good?

Once complete, engage students in a class discussion around their answers.