About Lesson
Practical Activity
AIM:
To investigate conditions necessary for germination
Materials
- Dry cotton wool
- 4 conical flasks
- Bean seeds
- Labels (4)
- Water
- Pyrogallic acid mixed with NaOH
- Ignition tube
Procedure
- Put some dry cotton wool at the bottom of 4 conical flasks.
- In each flask, place 5 healthy bean seeds on top of the cotton wool.
- Label flasks A, B, C and D.
Flask A
- Moisten the cotton wool by adding water.
- Place Pyrogallic acid mixed with NaOH in an ignition tube in the conical flask.
- Cork the conical flask to make sure its airtight e.g.
Flask B
Put flask B in a corner of the classroom e.g.
Flasks C
Moisten the cotton wool and keep the flask in a refrigerator.
Flask D
Moisten the cotton wool and keep the flask in a warm place.
- Record your observations after a few days.
Observations
Flask A
No germination due to absence of Oxygen i.e.
Pyrogallic acid mixed with NaOH absorbs Oxygen present in the flask.
Flask is airtight so no Oxygen enters into the flask
Flask B
No germination due to absence of water.
Flask C
No germination/ seeds took long time to germinate due to low temperature.
Flask D
Germination occurred due to presence of Oxygen, water and favourable temperature.
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