School science — 2: The home‐made back‐projector

Abstract

A lesson involving the demonstration of a scientific technique or the manipulation of a scientific intrument is often very difficult to perform, owing to the small size of the apparatus involved. This makes it difficult for a whole class to see at one time. To enable the pupils to see clearly what is happening in such cases, eg a class learning to use a balance, one can use a simple technique based on the slide projector and a daylight rear projection screen. It should be noted that any demonstration system should be readily available, easily set up, and convenient to use. The daylight rear projection screen helps to solve this problem. It is easily made. It requires no black‐out system. It is easily set up and above all it is most effective when viewed from the back of the class. Its only slight disadvantage is its narrow angle of view. To make such a screen is simple in the extreme. A piece of screen material was purchased for about £1 from the local photographic shop and mounted on the end of a large fibrite box, which had previously contained cornflakes. The size of the screen was 24in x 26in. A long box of about 4ft is necessary, to shield the screen from as much extraneous light as possible from the rear. The slide projector is mounted immediately at the back of the box and focussed on the screen.

Citation

Edwards, R.M. (1967), "School science — 2: The home‐made back‐projector", Education + Training, Vol. 9 No. 11, pp. 488-489. https://doi.org/10.1108/eb015889