SCOPE AND CONTINUITY OF SCIENCE 17

 ticular service to teachers who have two or more grades in the
 room. By keeping the chart in front of him while he does long
 range planning, the teacher can arrange for pupils from at least
 two grades to work together. By a careful selection of topics
 and problems, it would be possible to develop a two year "block"
 that would have balance as far as the six areas are concerned in
 each year.
 In Large Unit Planning. In planning large units of work
the chart should be of great assistance, especially when the
work cuts across several subject areas. By examining the so-
cial studies and science charts together, for example, many re-
lationships will be noted and occasions for integrating work will
suggest themselves.
 In Selecting Appropriate Materials of Instruction. In doing
long range planning, the teachers will again find the chart of
use in the selection of appropriate materials. Certain needs,
such as for films that are to be rented, can be anticipated far
enough in advance to permit proper ordering. Where under-
standing certain concepts calls for extensive use of library ref-
erences, the books can be assembled in time. A proper variety
of materials can also be planned. The chart will help the teacher
anticipate situations where experimenting, observing, field trips
and other forms of out-of-door education will be helpful. Some
forms of out-of-door education, such as a camping trip or excur-
sion to a State park, are extremely valuable but must be antici-
pated well in advance lest the opportune time both come and go
before the class can make the necessary plans.

Enlargement of Concepts from Lower to Upper Grades:
A Sample Treatment
 The organization of science work should provide for the
growth of children through constantly enlarging experiences.
Simple ideas introduced in the primary grades will lay a foun-
dation for understanding more complex ones in the middle and
upper grades. Most of the ideas introduced in the primary
grades are based on first hand experiences or observations. In
the middle and upper grades many of the ideas come from indi-
rect experiences representing events far away in time or space.
Furthermore, with more complex concepts, several ideas have to
be held in mind at once in new relationships in order to arrive
at a new or deeper understanding.
 The following sample treatment of the enlargement of con-
cepts on weather is presented here to show that what the casual
observer might call repetition is really extension. For example,
compare Number 8 under primary grades "wind is air in motion"
with Number 10 under intermediate grades, "Cold air is heavier