AIM OF THE EXPERIMENT: To split light into colours.
MATERIALS: a bowl holding a litre of water, a small bottle of clear nail varnish.
MATERIALS: a bowl holding a litre of water, a small bottle of clear nail varnish.
Изображение
Stand the bowl of water on a table where no direct light falls on it.
Hold the brush from the bottle of varnish over the bowl until a drop of varnish falls into the water.
Watch the surface of the water. Move your head about to look at the water from different places.
RESULTS: Rainbow colours shimmer on the thin layer of varnish spread over the water.
WHY? The varnish forms a thin film on the surface of the water. When light falls on the surface of the film, each ray is partly reflected by it. The rest of the ray reaches the bottom surface of the film and is reflected there too. The reflected rays add together, and we see shimmering rainbow colours. But we see them only when the film is of a certain thickness. If the film is too thick or too thin, the time the ray needs to pass through it and come back is either more or less than it should be, and there is no rainbow. METHOD:
Hold the brush from the bottle of varnish over the bowl until a drop of varnish falls into the water.
Watch the surface of the water. Move your head about to look at the water from different places.
RESULTS: Rainbow colours shimmer on the thin layer of varnish spread over the water.
WHY? The varnish forms a thin film on the surface of the water. When light falls on the surface of the film, each ray is partly reflected by it. The rest of the ray reaches the bottom surface of the film and is reflected there too. The reflected rays add together, and we see shimmering rainbow colours. But we see them only when the film is of a certain thickness. If the film is too thick or too thin, the time the ray needs to pass through it and come back is either more or less than it should be, and there is no rainbow. METHOD: