Investigating plastic

This task is about the physical properties of plastics.

This is a group task. You will work in your group for the entire task.

Play the game"Can you guess it?" Use the separate Game instruction sheet and Recording slips.
Complete the questions below. Share and discuss your answers with the rest of the class.
Complete the Group self-assessment sheet.

Our science rule for grouping plastic used the following property:

ii)

The science rules that the other teams wrote for our grouping were:

Rule for grouping	Is this an observable property?	Is this a measureable property?

Describe whether it was useful/ not useful to work as a group in this investigation.

Science investigations collect data/evidence to answer questions about the natural, physical world and the wider universe.

How might grouping and classifying plastics by their physical properties be considered a science investigation?

To finish the activity, complete the Group self assessment sheet. The team should discuss each statement, providing specific examples.

Game Instruction Sheet

Can you guess it? Aim of the game: Use a science way of working to separate 6 plastic items into 2 groups.

When we classify things in science, we work in certain ways. Scientists use observable and/or measureable properties to classify materials.

Your group will need to work as a science team to identify a property (observable and/or measurable) that can be used to separate the types of plastic into 2 groups.
Separate your objects into 2 groups according to the property you have chosen.
Record the rule you used to classify your plastic on the Our Rule slip of paper, e.g., the property we used to make our science rule is hardness.
Each team shifts to another team's table. Your team is to look at the objects in the two groups. Discuss amongst yourselves and identify the science rule that this team used to separate the plastic objects. Record your science rule for the two groups on the Their Rule slip of paper. Fold your paper and place in the post box.
Repeat step 3 for another three teams.
After looking at four other teams, each team returns to their own table to answer the question sheet.

Recording Slips

Our Rule

Names in our team: The property that we used to make our science rule is:

Our Rule

Names in our team: The property that we used to make our science rule is:

Our Rule

Names in our team: The property that we used to make our science rule is:

Group self -assessment sheet

Classifying and identifying materials in a science way. Team names:________________________________________________________ Date:________________________________ The property we used to classify (group) plastic in the game was _________________________
1	We thought of different observable properties before we made our rule for classifying.	Yes	No
2	We thought of observable properties that could be measured.	Yes	No
3	In our group we always discussed the different properties before we identified the properties others had used to classify.	Yes	No
4	We could always identify the observable property in the rule others had used to classify.	Yes	No
5	We found it hard to identify an observable property that could be measured in the rule others had used to classify.	Yes	No
6	It is useful for scientists to sometimes work together because:
7	An important thinking process that scientists do when classifying/identifying things is:

Peer assessment
When your team has completed the 'group self-assessment' discuss your results with another team in the class.

Listen to what the other team says about each statement in the 'group self-assessment'.

Ask the team to support their answers with examples from the game.

Task administration:

This task can be completed with pencil and paper and other equipment.

Equipment:

For each group - 6 common plastic objects (e.g., supermarket bag, lunch container, ruler, cup, comb, pen, spoon, glad wrap, empty milk container, etc)., a container with a slit cut in the lid, for a post-box]

NOTE: It does not matter if each group has different plastic objects.

Our trials showed that some of the science language used when investigating and talking about properties (including the word "properties" itself) is confusing to many students because they either apply the everyday meaning or they have a very narrow interpretation of the word. You can check students' understanding before you begin by using the table below, Science words you need to know. Other ARB resources that explore the science language of properties are The best mopper upper, P aper money for Monopoly (version A), and P aper money for Monopoly (Version B).

Science words you need to know:	Example:
classify: sort into groups that have something in common	We can classify fabric by whether it is waterproof or not.
property: a natural part of a material that can be used to identify and describe the material	Some properties are colour, hardness, and bendiness.
material: the stuff that anything is made of. Scientists call it matter.	Some examples of materials are plastic, wood, metal, wool and water.
observable properties: things you can see	Some examples are colour, stretchiness, and smoothness. Some examples are absorbency, stretchiness, and hardness.
measureable properties: things you can measure	Some examples of ways to measure are a ruler, a thermometer, or a scale that describes with words, e.g. very rough, rough, a little bit rough, smooth, very smooth.

It is suggested that this activity follow on from Paper money for Monopoly (version B), which identifies whether the students can identify and describe physical properties.
The task can be done as one complete activity or in two consecutive sessions.
The task is done in small groups (3-4 students).
Ensure that each group has an Instruction Sheet, Recording Slips and Group self-assessment sheet. The Recording Slips need to be cut up. Provide a post-box for them to post their recording slips.
Go through the instructions with the students before they begin the task, and check that they all understand what to do. You may prefer to give the instructions verbally.
The group self-assessment requires that the group 'consults' with another group. An alternative is to bring all the groups together for a class discussion.

Teaching and learning:

Background
The concept of property is an important science concept but it is also difficult to develop. In this task, the focus is on physical properties and the words used to describe these properties. At this level the scientific terms that apply to materials may be unfamiliar to many students; hence some everyday property terms are used in the task. A table that compares some of the scientific and everyday terms of physical properties can be found in Task administration.

Why is classifying and identifying, as a science investigation, important for students to know?
The common thread that links the different types of investigation is the collection of data/evidence to answer a question or understand a science concept. Students need to be aware that during classifying and identifying they are collecting data/evidence in order to answer a question, whether it is to separate materials or identify similar objects. In science investigations, the data is linked to science concepts and in this task the concept is physical properties of plastics. Other materials, e.g., rocks, soil, and wood, can be investigated using classifying and identifying.

Classifying and identifying is a science investigation that tends to be ignored as a type of investigation in the classroom. For further information on other types of science investigations go to science investigations.

Key competencies that could be strengthened through this activity are:
Thinking
Students are encouraged, through the game, to think creatively and critically as they use their understanding of properties to group materials, and to solve how other groups completed the task. The self-assessment task provides a structure for students to reflect on their thinking and problem solving skills, and their ability to work co-operativ90ely.

Nature of science ideas that are a focus of this activity are:
Understanding about science: Students are creating 'rules' for grouping plastic based on their group's collective knowledge and understanding of properties of materials. In doing so they may develop an understanding of what it means to work in a scientific way, in particular how the scientific community works together, providing evidence to support their ideas.
Investigating in science: Students are using their prior knowledge of properties and the purpose of science investigations to engage with a specific type of science investigation – classifying and identifying. In this process students further develop their understanding that science investigations collect data/evidence to answer questions.

Diagnostic and formative information:

The Year 6 trial students knew little about the physical properties of materials. The word "property" caused problems. They were familiar with it in everyday terms of "possessions/belongings” or “home" but its scientific meaning was foreign to most. This is a good example of a word with a specific scientific meaning that is different to its everyday meaning.

When another resource was trialled, some students discussed the object, rather than the material it was made from. An example: a plastic bag can hold things.

Some students had a very narrow view of measuring, usually involving a ruler. Some were able to think of other ways of measuring, but did not develop any sort of scale for making comparisons.

Trial group responses indicate that students were able to collaborate in a collective decision making process. They were highly motivated to play the game. General trends in the trials showed that the students:

Found it difficult to think reflectively about their collaborative effort. Their group self-assessment discussions gave an indication of whether the members had the collaborative skills of working as a team;
Lacked understanding of the purpose of a science investigation; and
Did not recognise classifying and identifying as a science investigation.

Next steps:

Developing scientific vocabulary associated with physical properties

A necessary prerequisite for completing this task is being able to observe, describe and compare physical and chemical properties of common materials (Level 2 in the new curriculum). For ARBs that have this focus go to Other resources.
Change the science context of this activity from plastic to other familiar materials such as soil and/or rocks, wood, metal, or paper to provide further opportunities and experiences to use the appropriate science vocabulary to describe their physical properties.
For more information go to Language barriers.

Developing ideas about classifying plastics
Students can examine more closely the different sorts of plastics (this may be done in the context of recycling).

Developing classifying and identifying as a science investigation
Especially if fair testing is the only investigation that students think of as scientific, look for opportunities to discuss the different sorts of investigations students and/or scientists are carrying out. Some questions to ask are:

What question is being investigated?
Is this the best type of investigation to answer the question? Why or why not?
Why might fair testing not be the best investigation in this particular case? (Other types of investigation can be substituted in this question.)

Extending ideas about measurement

Encourage students to think about how they could compare degrees of a property that cannot be measured with a ruler. Examples of descriptive (qualitative) scales used in science are the Beaufort scale, used to describe the effect of wind forces, (this scale also has a numerical component) and the Modified Mercalli scale that describes the effects of earthquakes at different sites. These sorts of scales are used less in science now because of developments in technology, but are useful for students to construct, especially when they don't have the equipment to measure. 5 point scales are another descriptive scale that students can construct.
Try using some of these scales (the Beaufort scale is an ideal one because weather is accessible to students). Compare different students' judgements using the scale.
Discuss which sorts of scales are more accurate and why. Also discuss which are more useful in particular circumstances.
Some students may be ready to consider the nature of science idea that scientists construct scales so they can make comparisons between two or more objects or events.

Extending to chemical properties
Once students have investigated physical properties, they can explore chemical properties. We cannot see the chemical properties of materials until they react with other substances to form new substances. However, we recommend for hands on investigations to use contexts other than plastic. Mixing baking soda and vinegar is fun and safe (there are some exciting activities in Making Better Sense of the Material World), rusting metals, and, with care, burning (not plastics, as some produce toxic gases) are some contexts suitable for younger students. Asking students to compare the physical properties of the original substances with the new substances produced will provide opportunities for them to practise using their scientific vocabulary.

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Investigating plastic

Investigating plastic