Back to: BIOLOGY NEW LOWER SECONDARY CURRICULUM BOOK 2
Comparing the drainage of sandy clay and loam soils samples
Duration: 80 Minutes
Key question: What is the difference in the water drainage properties of the different types of soil?
What you need
- measuring cylinders (3)
- funnels (3)
- water
- filter papers or pieces of cotton
wool soil samples: sandy soil, clay soil and loam soil
What to do
- In groups, using the materials you
have been provided with, design an experiment to compare the drainage properties of loam, sandy and clay soils.
- Conduct the experiment you
Have designed and then write a report about your investigation.
- Present your report to the rest of the class.
Suggested responses
Observation: Water passes faster through sandy soil than through loam and clay soils. Sandy soil gives the first drop of water and clay soil gives the last drop. So much water is collected in the cylinder with sandy soil and the least water is collected in the cylinder with clay soil.
Conclusion: Sandy soil drains faster than loam and clay soil.
Explanation: Sandy soil has larger air spaces which enable water to drain through more rapidly and on the other hand, clay soil retains more water than sandy and loam soils. This is because clay soil .has few air spaces and small particles. Loam soil has medium drainage.
c) Capillarity
Stimulate the learners’ thinking by asking them how they are able to sip a soda through a straw!
Let them relate it to the rise of water from the bottom layers of the soil to the top layers through soil particles. This is called soil capillarity. Guide them to investigate this in activity 1.3(c).
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