64 TEACHING SCIENCE IN SECONDARY SCHOOLS

 SECTION 6. AUDIO-VISUAL DEVICES
 Audio-visual aids provide sensory experiences which, added
to common teacher-textbook situations, will vitalize science
teaching. The term "aids" implies addition, but the proper use
of these materials demands their incorporation into the course
as an integral part.
 The visual aids are numerous and flexible. The teacher will
spend much time examining and appraising them to fit par-
ticular needs. The science course that is well rounded with ade-
quate audio-visual aids will give high returns to students in
interest, learning, and retention.
 The blackboard is one of the most common and least effective-
ly used visual aids. Can the students see it? A small investment
in a fluorescent light can "light the way." Is it kept clean? Is
the handwriting plain? Are the diagrams and sketches clear?
Use of colored chalk will simplify labeling and make parts of dia-
grams stand out more clearly.










THE BULLETIN BOARD-
 The bulletin board is the most variable, the least often varied,
 aid. Keep it current, attractive, and interesting. Opportunity
 for students to handle the bulletin board material is afforded.
 Student competition in this activity is a good motivation. File
 much of the material for future use. Posters, charts, and the like
 may be obtained free, or at nominal charge, from many com-
 mercial sources such as DuPont, Westinghouse, General Motors,
 General Electric.