(2) By using a soap solution instead of the soap, as in (1).
(3) By rubbing on a wash-board.
In each case dry the cloth and compare with an original piece.
After the results of the experiments have been discussed, the pupils may formulate a series of "points" to be observed in the washing of woollen fabrics.
Cotton fibres magnified
Linen fibres magnified
Woollen fibres magnified