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Activity 13.5 Class 10 Science

Activity 13.5: NCERT book Science Class 10

Ever wondered what happens to waste after it’s thrown away? Activity 13.5 in the Class 10 NCERT Science book explores how different waste materials decompose, teaching us about waste management and the roles of biological and physical processes.

Understanding Waste Decomposition: Activity 13.5 from Class 10 Science

Materials Needed

  • Various household waste materials (e.g., kitchen waste like spoilt food, vegetable peels, used tea leaves, milk packets, empty cartons, waste paper, empty medicine bottles/strips/bubble packs, old clothes, and broken footwear)
  • A pit in the school garden or an old bucket/flower pot
  • Soil (to cover the waste)
  • Water (to keep the materials moist)


  1. Collection of Waste: Start by collecting a variety of waste materials from your homes. This should include both biodegradable and non-biodegradable items.
  2. Burying the Waste: If you have access to a school garden, dig a pit and bury the waste materials in it. If not, use an old bucket or flower pot. Cover the waste with at least 15 cm of soil.
  3. Maintenance: Keep the waste moist by watering it regularly.
  4. Observation: Observe the buried waste at 15-day intervals to note which materials remain unchanged and which ones decompose.


  1. Biodegradable Materials: Over time, materials such as vegetable peels, used tea leaves, and food scraps are likely to decompose and change their form and structure. These materials are broken down by bacteria and other saprophytes present in the soil.
  2. Non-Biodegradable Materials: Items like plastic bags, empty medicine bottles, strips, and certain synthetic fabrics will remain largely unchanged. These materials do not easily break down through biological processes and may persist in the environment for a long time.
Material TypeExamplesDecomposabilityApproximate Time Taken for Decomposition
BiodegradableVegetable peels, Food scraps, Used tea leavesDecomposes easily1-2 months
Paper, Cardboard, Cotton clothesDecomposes fairly easily2-5 months
Natural fabrics (wool, silk)Decomposes1-5 years
Non-BiodegradablePlastic bottles, Plastic bagsDoes not decompose easily450 years
Glass bottles, Metal cansExtremely slow decomposition1 million years (glass); 50-200 years (metal)
Synthetic fabrics (polyester, nylon)Extremely slow20-200 years
Styrofoam and Bubble wrapDoes not decomposeNever (effectively permanent)

Explanation of the Decomposition Process

When organic waste like vegetable peels and food scraps are buried in soil, they undergo a biological decomposition process. Microorganisms such as bacteria and fungi break down these organic substances into simpler compounds. This process releases nutrients back into the soil and is an essential part of the nutrient cycle.

Equation for decomposition:
$$ {C_6H_{12}O_6 \rightarrow CO_2 + H_2O + energy} $$

In contrast, non-biodegradable materials like plastics are resistant to microbial breakdown. They persist in the environment and can be broken down only by physical processes like heat and pressure over very long periods.


  1. Biodegradable materials decompose relatively quickly due to microbial activity.
  2. Non-biodegradable materials like plastics and synthetic fabrics do not break down easily and persist in the environment.
  3. Effective waste management requires understanding these differences to properly handle and dispose of various types of waste.

Questions and Answers

What types of waste materials decompose the fastest?

    Organic materials like vegetable peels and food scraps decompose the fastest due to microbial action.

    Why do non-biodegradable materials not decompose easily?

      Non-biodegradable materials do not provide suitable substrates for microorganisms and hence are not broken down by biological processes.

      What role does moisture play in the decomposition process?

        Moisture is essential for microbial activity, as it enhances the breakdown of organic matter by providing a suitable environment for microorganisms to thrive.

        What can we learn about waste management from this activity?

          Proper segregation of waste into biodegradable and non-biodegradable categories is crucial for efficient waste management and environmental conservation.

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          Activity 13.4 Class 10 ScienceActivity 13.5 Class 10 Science

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