Common errors in a demonstration lesson are given below:
(i) The apparatus may not be ready for use.
(ii) There may not be an apparent relation between the demonstration experiment and the topic under discussion.
(iii) Black board summary is not up to the mark.
(iv) Teacher may be in a hurry to arrive at generalization without allowing sufficient time to arrive at this generalization from facts.
(v) Teacher may sometimes fail to ask right type of questions.
(vi) Teacher sometimes may use a difficult language.
(vii) Teacher sometimes takes to talking more which may mar the enthusiasm of the students.
(viii) Teacher may not have allowed sufficient time for recording data etc.
(ix) Teacher has not given proper attention to supervision.