In this lesson students consider how materials are remade or recycled into new products for the good of the environment.
They conduct a guided fair test to investigate the effects of recycling processes on paper. They record their observations and compare their findings with others.
View the video clip Visiting a recycling plant. Discuss how once the paper products are sorted from all other types of recyclables and rubbish, the paper products are further sorted into types including cardboard, newspaper and office paper. Display the prepared types of paper and cardboard (see Background information for details). Discuss how the properties of each paper product can be quite different and how this influences the way they are recycled and what they will be remade into.
Explain that in this science lesson the students will investigate how different types of paper and cardboard change during the recycling process.
- Recall from the video the main things that happen to paper products once they are separated and sent to the mill (washing to clean and remove dyes and unwanted materials, broken into smaller parts, put through rollers to squeeze out water and reform into new sheets). Ask students to suggest how the properties of paper change once it is wet.
- Show two jars of the same size with lids, each containing a piece of crêpe paper of the same size. Ask students to predict what will happen to the paper when you put the lid on and shake one (air), then add water to the other and shake (use the shaking method that will be used in the investigation). Demonstrate. Discuss how the water changes the properties of the paper so that it can be recycled.
- Recall from the video that once the paper had been washed clean and softened in the water, it was mixed and blended into fine pulp. Ask students to predict whether all the different types of paper given to them would change with the same amount of blending and mixing.
- Explain that the students will investigate how much blending and mixing different types of paper and cardboard need to get the materials to start breaking apart.
- Distribute the worksheet Paper recycling investigation. Model the investigation before students work in groups to conduct their own investigation. Conference with students as they work.
Teacher note: Full instructions for guiding students through the ‘Paper recycling investigation’ investigation can be found in Background information.
Regroup with student pairs sitting with their completed investigation tables. Compare and discuss findings. Fill out the class table in the class science journal with a representative number of shakes. Explain that in the next lesson the students will make something useful by recycling paper. Discuss which paper might be best to use given their investigation results. Ask students which paper will blend and mix easily but is also ideal to recycle (not tissues or kitchen towel).