OVER HEAD PROJECTOR:
The over head projector is the most used in all a.v. aids.
It projects transparencies with brilliant screen images suitable for use in a
lighted room. The teacher can write or draw diagrams on the transparency while
he teaches; these are projected simultaneously on the screen by the OHP.
During presentation:
§ Keep the screen
above the heads of the participants.
§ Keep the screen in
full view of participants
§ Make sure you are
not blocking any ones view when presenting.
§ Darken the room
appropriately by blocking out sunshine and dimming near by.
§ Turn the screen
off between slides if you are going to talk for more than two.
§ Talk to the
audience, not to the screen
Purposes:
§ To develop concepts
and sequences in a subject matter area.
§ To make marginal
notes on the transparencies for the use of the teacher that can carry with out
exposing them to the class.
§ To test students
performances, while other classmates observe.
§ To show
relationships by means of transparent overlays in contrasting color.
§ To give the
illusion of motion in the transparency.
Advantages:
§ It permits the
teacher to stand in front of the class
while using the projector, thus enabling her to point out features appearing on
the screen by pointing to the materials
at the projector it self and at the same time, to observe the students reactions to
her discussion.
§ Gains attention of
the student
OVER HEAD
TRANSPERENCIES:
Transparencies are popular instructional medium. They are simple to
prepare and easy to prepare and easy to operate with the over head projector
which is light weight.
A 10*10 inches sheet with printed, written or drawn material
is placed on the platform of the projector and a large image is projected on a
screen behind you.
The projector is used from near to the front of the room
with the teacher standing or sitting beside, facing the student.
Guidelines for making
effective transparencies:
· Have one
main idea an each transparency.
· Include only
related figures and diagrams.
· Use simple
lettering style in writing.
· Use diagrams
in proposition to its lettering.
· Keep the
message clear and simple.
· Emphasize
the key messages.
· Use color
and lettering with discretion.
Advantages:
· Permits face
to face interaction with the students.
· Can be used
in daylight conditions.
· Can present
information in systemic developmental sequences.
· Requires
limited planning and can be prepared in variety of inexpensive methods.
· Easily
available.
THE OPAQUE PROJECTOR
Opaque projector is the only
projector on which you can project a variety of materials ex: - book pages,
objects, coins, postcards, or any other similar flat material that is
non-transparent.
The opaque
projector will project and simultaneously enlarge, directly from the originals,
printed matter, all kinds of written or pictorial matter in any sequence
derived by the teacher. It requires a dark room, as projector is large and not
reality movables.
Advantages:
· Stimulates
attention and arouses interest.
· Can project
a wide range of materials like stamps, coins, specimen, when one copy is
available.
· Can be used
for enlarging drawings, pictures and maps.
· Does not
require any written or typed materials, hand-written material can be used.
· Helps
students to retain knowledge for longer period.
· Review
instructional problems.
· Test
knowledge and ability.
· Simple
operation.
Disadvantages:
· Costly equipment.
· Needs to use
it with care.
· Needs a dark
room for projectio
SLIDE PROJECTOR
A
slide is a small piece of transparent material on which a single pictorial
image or scene or graphic image has been photographed or reproduced otherwise.
Slides
are a form of projected media that are easy to prepare. They are still pictures
on positive film which you can process and mount individually yourself or send
to a film laboratory. The standard size of the slides is 2 “X 2 “any 35mm
camera will make satisfactory slides.
Types of slides
1. Photographic
slides: 2” X 2”
3” X 4”
a) Black and
white
b) Colored
2. Hand made
slides: can be made with
a) Acetate sheet
b) Cellophane
c) Etched glass
d) Plain glass
e) Lumarith
Slides can
be made from photographs and pictures by teachers and pupils taking photographs
and snapshots when they go on fieldtrips for historical, geographical, literacy
or scientific excursions.
The arrangement of slides in proper sequence, according to
the topic discussed, is an important aspect of teaching with them.
Advantages:
1. Requires only
filming, processing and mounting by self or laboratory.
2. Results in
colorful, realistic, reproduction original subject.
3. Preparation
with any 35mm camera for most uses.
4. Easy to revise
and up-date.
5. Easily
handled, stored and re-arranged for various uses.
6. Can be
combined with tape narration or can control time for discussion.
7. May be adapted
to group or individual use
FILMSTRIPS
Film strips are sequence of transparent still pictures with individual
frames on 35mm film. A tap recorded narration can be synchronized with film
strip.
Each strip contains from 12 to 18 or more pictures. It is a
fixed sequence of related stills on a roll of 35mm film or 8mm film.
PRINCIPLES
1. Preview
filmstrips before using them and selected carefully to meet the needs of the
topic to be taught.
2. Show again any part of the filmstrip needing
more specific study.
3. Use filmstrip
to stimulate emotions, build attitudes and to point up problems.
4. It should be
introduced appropriately and its relationship to the topic of the study brought
out.
5. Use a pointer
to direct attention, to specific details on the screen.
Types of filmstrip:
1) Discussion
filmstrip: it is continuous strip of film consisting of individual frames
arranged in sequence usually with explanatory titles.
2) Sound slide film: it is similar to
filmstrip but instead of explanatory titles or spoken discussion recorded
explanation is audible, which is synchronized with the pictures.
Advantages:
1) Are compact,
easily handled and always in proper sequence.
2) Can be
supplemented with recordings.
3) Are
inexpensive when quantity reproduction is required.
4) Are useful for
group or individual study at projection rate are controlled by instructor or
user.
5) Are projected
with simple light weight equipment.
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