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Question
Take 2 slices of bread. Place one slice in a plate near the sink. Place the other slice in the refrigerator. Compare after three days. Note your observations. Give reasons for your observations.
One slice of Bread
in a plate
near the sink
Other slice of Bread
in a plate
in the Refrigerator
Show answer
Answer
Slice near the sink
Slice in the refrigerator
Warm and damp.
Cold and dry.
Microbes grow well in these conditions.
The cold slows microbes down.
Fuzzy mould appears after three days.
The slice stays fresh for much longer.
The slice near the sink grows mould; the one in the refrigerator stays fresh.
Explanation
- Near the sink it is warm and moist, so mould (a fungus) grows.
- The refrigerator is cold and dry, so microbes cannot grow well.
- So the fridge slice stays fresh much longer.
Warmth and moisture let mould grow; cold slows microbes, so the fridge slice stays fresh.
← Back to: 2.4.1 Key players in cleaning the environment
📖 Important Definitions
- Decomposition — Breaking down of dead matter by microbes into simpler, nutrient-rich substances.
- Manure — Nutrient-rich material formed when microbes break down plant and animal waste.
- Biogas — A fuel gas (mainly methane) released when microbes decompose waste without oxygen.
📝 Summary - What we have learnt
- Fungi and bacteria break plant waste into nutrient-rich manure.
- This breakdown is called decomposition.
- Microbes recycle nutrients back to the soil.
