Lesson 28

Lesson 28: Some Waste Can Decay, Some Cannot Decay

Learning Objective

Understanding that some waste can decay

Syllabus Correlations

· Theme: Investigating Materials

· Learning Area: Waste Management

· Learning Objective: Understanding that some waste can decay

Learning Outcomes:

Pupils should be able to:

· state that certain waste can decay.

· give examples of waste that can decay.

· give examples of waste that do not decay.

· state that microorganisms can cause waste materials to decay

Concept(s) Introduced:

· what examples of waste that can and cannot decay;

· the use of microorganisms to decay waste materials.

Skills Covered:

· Observing, classifying, making inferences, interpreting data, making conclusions, comparing and contrasting.

Vocabulary/ New Words:

biodegradable, decay, organic waste, waste

Value(s) Incorporated:

· Having an interest in and curiosity about the environment.

· Being diligent and persevering.

· Realising that science is a means to understand nature.

· Thinking rationally

· Analysing the things around us

Materials Needed:

-

Point(s) to Note:

Explain what waste can and cannot decay as well as the effect of microorganisms on waste materials.

Teaching Strategies
Set Induction	Show the images of waste that can and cannot decay. Ask pupils to identify which waste can decay and also those that cannot decay. Ask pupils how to make the identification. Component: Introduction
Step 1	Play the content component. Teacher explains waste can either decay or cannot decay. Ask pupils whether they know what waste that can decay from the pictures. Play the content component. Teacher explains the concept of decay. Ask pupils what examples of waste that can decay. Teacher highlights common examples of organic waste that can decay such as organic waste. Explain other examples like papers, cardboards and woods. Ask pupils whether they know the term to describe waste that can decay. Teacher introduces the concept of biodegradable waste. Play the content component. Ask pupils what the examples of waste that do not decay are. Ask pupils whether they know the term to describe waste that cannot decay. Teacher introduces the concept of non-biodegradable waste. Ask pupils what happens to this type of waste in long run. Play the content component. Ask pupils what the effects are when non-biodegradable waste is burned to the environment. Explain that the waste may give out poisonous gases that affect human health. Ask pupils what happens when waste do not decay. Explain that there will be accumulation in the environment. Play the content component. Ask pupils whether there is another way to cause waste to decay. Teacher highlights that microorganisms can cause waste decay. Ask pupils what these microorganisms are also known as. Teacher introduces what decomposers are. Play the content component. Ask pupils how decomposers obtain food. Teacher explains that decomposers obtain food by breaking down waste. Ask pupils whether they know how decomposition happens. Show the video on decomposition. Ask pupils to discuss on the benefits of decomposition to the environment. Teacher highlights that decomposition returns nutrients to the soil. Component : Content
Step 2	Play the activity component. Ask pupils to drag and drop examples of waste into the categories of either it can or cannot decay. Tell pupils to observe the waste well to make the correct identification. Component: Activity
Step 3	There are five questions in this component covering the learning outcomes. Questions 1 to 3 are objective questions. Q4 is a drag and drop activity. Pupils drag and drop the correct answers for the questions. Q5 consists of true or false questions. Pupils need to identify whether the statements are true or false. Use evaluation sheets to assess the pupils’ understanding of this lesson. Component: Evaluation
Step 4	A case study on the decaying process. Ask pupils what undergoes decaying process. Ask pupils to discuss the benefits of decay to the environment. Teacher explains the effects of decayed animal to produce nutrients that help soil and in turn help the growth of plants. Healthy grass is the source of food for animals. Component: Extension
Conclusion	Conclude the lesson by playing this component to further reinforce understanding of the lesson. Help pupils to differentiate between waste that can and cannot decay. Emphasise how microorganisms can help to decay waste. Component : Summary