This article completes the survey of mistakes and their causes which affect the presentation of physics and other sciences in schools and in popular science. It is concerned with: commonly used but unsound analogies; diagrams which have been copied carelessly from various sources; misuse of scientific terminology or the use of unsuitable popular terms; the effects of words having different meanings or quantities being given different values in different times and places. As so much understanding depends on finding the relationships between ideas, a section gives illustrative examples of misleading association where there is inadequate basic knowledge. As with parts 1 and 2, only a very incomplete account of the problem is given and it is only by implication that fundamental causes in university education can be indicated.