A Contribution for the Construction of Parabolic Mirrors

TL;DR

This paper introduces a low-cost, practical method for constructing parabolic mirrors using spinning liquid plaster and simple materials, enabling educational exploration in schools and universities.

Contribution

A novel, inexpensive procedure for creating parabolic mirrors using rotational casting of plaster and subsequent molding techniques.

Findings

Successfully produced parabolic mirrors with simple materials.

Method suitable for educational purposes in schools and universities.

Provides a practical demonstration of physics principles involved in paraboloid formation.

Abstract

We present a new procedure for the construction of parabolic mirrors using low cost materials. We build a spinning system composed of nylon threads, fish hooks and a plastic bucket. We pour liquid plaster into the bucket and set it in constant rotational motion relative to the earth. A liquid substance assumes a parabolic profile when spinning at constant angular velocity relative to an inertial frame under the influence of an uniform vertical gravitational field. By keeping the bucket under rotation for a long time, the plaster solidifies into a parabolic format. We utilize this solidified plaster paraboloid as a model to construct a counter-mould of glass fibre and resin. Over this counter-mould it is placed stretched laminated foil and then it is poured thick plaster over it. In this way it is obtained a parabolic mirror made of laminated foil and plaster. Our only objective here is to present a new method for the construction of parabolic mirror using low cost materials. This allows further exploration of this procedure by teachers and students either in high-schools or in universities.