can be made of this method is in the mere observation of what takes
place. Nothing which the child notices correctly need be rejected,
no matter how far removed from the chief event on the object of the
experiment. Care that the pupil shall see all, and separate the
essential from the accidental, is all that is necessary.

But the original investigator assigns reasons, and with care the
children may be allowed to attempt that. This, however, should not be
carried far; incorrect explanations should be criticised; and the class
should at length be given all the elements of the correct explanation
which they have not determined for themselves. Later, pupils should be
encouraged to name related phenomena, to mention things which they
have seen happen which are due to associated causes, and to suggest
variations for the experiment and tests for its explanation. Good
results may be made to follow this kind of work even with very young
pupils. A child grows in mental strength by using the powers he has, and
mistakes seen to be such are not only steps toward a correct view of the
subject under consideration, but are steps toward that habit of mind
which spontaneously presents correct views at once in study which comes
later in life.

Another method is this: The pupil may know what is expected to happen,
as well as the conditions given, and held responsible for an observation
of what does happen and a comparison of what he really observes with
what he expects to observe. Explanations are usually given a class,
often in books with which they are furnished, instead of being drawn
from them, in whole or in part, by questioning, when physical science is
studied in this way. Indeed, this method is a necessity when text books
are used, unless experiments from some outside source are introduced.