TEACHING SCIENCE IN SECONDARY SCHOOLS


 Fortunately, the things that must be had for experimental
chemistry are inexpensive. Many of the most useful chemicals
are cheap, and it is surprising what a nice assortment of simple
glass and porcelain utensils a few dollars will buy. In contrast
to physics, there is little advantage in bringing substitutes for
this apparatus from home; for a cup costs more than a test tube,
a saucer as much as an evaporating dish, and drinking glasses, if
used instead of beakers, are sure to break when heated.
 1. FURNITURE FOR THE SIMPLEST LABORATORY
 a. Shelves. The first things to build are shelves along the
walls, head high and a foot more, shallow (not more than 6
inches in depth), the upper rows 10 inches apart in the clear for
ordinary bottles, the two lower rows 15 inches apart for taller
ones. Locate these in the place most convenient for student ac-
cess. There may be two or more sections; the total running
length should be from 10 to 15 feet. These are the students'
shelves.
 There should be another set of shelves from which students
are not permitted to take supplies. They should extend to the
height you can reach while standing on a chair. Shelves should
be 10 inches wide and 10 inches apart for storage of chemicals
in original packages. The two lower shelves should be 16 inches
wide and 24 inches apart, for glassware and other apparatus.
Use all the length conveniently available; upon these shelves
your laboratory will grow.
 It is rarely possible, in the small school, to have a special store-
room. It is not a necessity; it is really an advantage for students
to see constantly the chemicals in the form purchased. These
must be protected against indiscriminate use, however. A few
chemicals and pieces of apparatus should be kept under lock
and key to prevent certain mischievous uses which are obvious:
for example, the blue-glass plates, the labels, gold leaf, platinum
wire, magnesium ribbon, denatured alcohol, yellow phosphorus,
metallic sodium and potassium, mercury, and carbon. bisulfide,
should be locked in a carpenter's toolbox, a small trunk, or a
strong box with hasp and padlock. Sometimes glass and porce-
lain must be similarly protected; ordinary chemicals are rarely
molested.