FINDING OUT FOR THEMSELVES

A good order for this session might be:

Section 1 – outside - introduction

• Students look at an example of soil erosion (12)

• All students collect soil samples outside (3)

Section 2 – inside class

• Students examine their soil samples and decide what is in them (6)

• Explain: soil consists of small particles (4)

• Students look for black colour in soil – this may be humus (8)

• Explain: humus is the remains of dead plant and animal matter (7)

Section 3- inside class

• Students examine soil sample – are the particles bound together? (11)

• Explain: soil is bound together by humus (2)

• Explain leaching: dissolving of soluble matter out of the soil, including much of the humus. (1)

• Explain: rain water causes leaching and loss of humus (9)

• Explain: if rain hits soil without much humus it will be washed away (5)

• Notes to summarise the topic (13)

Section 4 – outside - conclusion

• Students look again at soil erosion: can we explain how soil is being washed away? (10)

This moves:

• from known (soils) to unknown (humus and leaching);

• from simple (soil particles) to complex (leaching);

• from particular (this soil) to general (all soils);

• from observation (look at erosion and soils) to reasoning (causes of erosion;

• from visible (soil) to things which cannot be seen (leaching);

• from practical (collecting and looking at soil) to theory (explaining what they see).

(Note: this session does not use abstract ideas.)

The whole emphasis in the session is on students finding out for themselves, although it is a difficult topic and a teacher might at first think that the only approach is through telling the students everything. Always look for an alternative way. Notice also that the observation (practical) and explanation (theory) are mixed together in the way suggested in Summary sheet B15