Teacher Preparation:

Overarching learning goal: In this activity students learn that waste has a huge impact on marine environments and recognise that disposing of waste appropriately can help marine biodiversity considerably.

Teacher content information: The Great Pacific Garbage Patch is a vast floating mass of plastic debris that has accumulated in the Pacific Ocean. If students are unfamiliar with the Great Pacific Garbage Patch, begin this activity by asking students to read The Ocean Cleanup information on The Great Pacific Garbage Patch, (theoceancleanup.com/great-pacific-garbage-patch/).

The sad truth of the Great Pacific Garbage Patch is that about 80% of the material floating around in there comes from the land, and much of it is made up of plastic bags, bottles and various other plastic items that we humans use in our everyday lives.

Cool Australia Presents Waste from Cool Australia on Vimeo.

See what other schools are doing by exploring recent case studies in the Waste Authority Western Australia newsletters. (wasteauthority.wa.gov.au/wss)

Discuss with students how they could conduct an experiment to test the breakdown of different types of waste under different conditions. Students could then design their own experiment or use the design below.

Teaching Sequence

Step 1

Explain to students that in this activity, students will conduct an experiment to test the decomposition rates of several types of waste to determine which ones break down quickest. The bags will be tested in seawater and freshwater. This experiment will take several months and can be revisited at several points during this time. Students can work as a class or in small groups.

Step 2

Begin the experiment by asking students to look at the list of Top 10 Marine Waste Items:

hard plastic remnants
cigarette butts
plastic lids
foam packaging
soft plastic remnants
plastic food packaging
plastic drink bottles
fishing line
broken glass and ceramic
straws/cups/plates/cutlery/confection sticks.

Where do these items come from? Which ones are related to industry (e.g. shipping, fishing, energy production etc) and which ones are related to personal consumption and households? You will find that most marine waste is attributed to personal consumption and households. However, it is important to note that waste relating to industrial activity - such as fishing nets and line - have devastating affects on marine life.

Step 3

Select your waste

Select three types of waste from the 'Top 10 Marine Waste Items' list below and find two examples of each. You may find these items at your school (remember to use gloves or tongs to collect waste). Ask students to make some predictions about what will happen to waste in the seawater and freshwater (using the Student Worksheet).

Step 4

Test your waste breakdown

To test your waste breakdown, you will need two buckets 3/4 filled with water. One bucket will represent freshwater while the other will represent seawater. You will need to add salt to this bucket to make the water saline. NOTE: seawater has a salinity of about 3.5% - how many grams of salt will you need per kilo of water? Remember to label your buckets!

Step 5

Watch your waste breakdown.

Add one of each waste items to each of the buckets. Place your buckets next to each other in the sun and leave for 3 to 4 months, checking the waste items every 2 weeks to see if there have been any changes. Record the results on the worksheet and by taking photos.

Assessment/Reflection

Step 1

Ask students to complete the questions on the student worksheet, including the reflection questions.

Step 2

Once complete, ask groups to share the results of their experiments, discussing which type of bag decomposed the fastest and which waste was the slowest. How did this result compare to the expected results suggested by the class prior to conducting the experiment? Also ask students to share the answers to their reflection questions:

Explain the results of this experiment in your own words and why you think some waste broke down faster than others.
Which results of this experiment were you surprised by?
How would you improve this experiment if you were to repeat it?
What does this experiment suggest about the things that we use in our lives and how it might impact on the natural environment, particularly on the oceans?

Homework/Extension

1. Ask students to undertake research into what manufacturers mean by “biodegradable”, for example:

What sorts of products are used to increase the decomposition rates of biodegradable products (e.g. corn starch or bamboo)?
Do any of these products cause other problems for the environment?
Are there government or waste industry guidelines on what biodegradable is or should be, and what do these guidelines require (i.e. that biodegradable products break down within 1 to 10 years)?
Are these guidelines and regulations acceptable for ensuring environmental health?

Students can write a report or create a poster that describes the results of their research.

2. Students could repeat the experiment with other types of waste on the list of Top 10 Marine Waste Items

Seal the Loop - Marine Waste Breakdown

Go to

Summary

Learning intentions:

Students will...

Lesson Guides and Printables

Lesson Details

Curriculum Mapping

Resources Required

Additional Info

In this lesson