PRIMARY PHYSICS
forces, energy and optics: the principles behind Newton’s science
Primary Physics: forces, energy and optics: the principles behind Newton’s science is the latest addition to the international award-winning series Primary Physics. They are easy-to-follow workbooks for young children, teachers and parents, that use simple, hands-on experiments to produce a firm foundation and genuine understanding of scientific principles. The instructions are simple, without complicated equations, and lead students to think and solve problems. The topics covered in Primary Physics: forces, energy and optics: the principles behind Newton’s science are: Newton’s 3 Laws of Motion, gravity and planetary orbits, forces, energy, optics and also a special section to accompany an amusement park excursion.
Primary Physics: forces, energy and optics: the principles behind Newton’s science is really all about our everyday life. Isaac Newton strove throughout his life to understand the laws of nature—why things work the way they do: why an apple falls off a tree to the ground, why the planets can be seen to move in the night sky, why the moon circles the earth, what causes the tides. In order for us to appreciate the genius of Newton’s science, it is important to study the foundations upon which his work is built. The lessons in Primary Physics: forces, energy and optics: the principles behind Newton’s science introduce students to Newton’s work through a carefully designed series of hands-on experiments and the beginning of the scientific method that Newton promoted and scientists have used ever since.
At the end of this book are instructions for you to carry out some of the very same experiments that Newton did with light. When you have completed this book, you will have a greater understanding of how everyday events in our lives are operating under the laws of physics, and Newton’s contribution to bringing them to us.
NOTE: This book is comprised of “First Science Books 3 and 4” plus some additional experiments and an important section on optics. The format is more appropriate for the older primary students.
Author’s Note
It is commonly claimed in textbooks, academic journals, diagrams, and online resources that white light dispersed by a prism can be recombined into white light by passing it through a second, identical prism oriented in opposition to the first. Despite how widespread this claim is, it is incorrect. Attributions of this claim to Isaac Newton are also wrong.
In Opticks, Newton explicitly describes using two prisms with a lens placed between them. He demonstrates that the lens is essential for recombining the dispersed colours into white light. Two prisms alone will not achieve this result. Newton is clear on this point.
It is striking that so many reputable textbooks and educational resources continue to repeat this error. Centuries of misrepresentation of Newton’s findings have gone largely unchallenged, and this deserves correction for the benefit of both teachers and students.
I personally attempted for four years to recombine white light using only two prisms, following the procedure commonly described in textbooks, and consistently failed. This led me to re-examine the original sources, including Newton’s Opticks, where it became clear that Newton’s work has been inaccurately reported. Light does not recombine after passing through two prisms alone, and Newton explicitly states this.
Teachers who repeat the experiment correctly—using a lens as Newton did—can return to their classrooms with a more accurate and far more interesting account of scientific investigation: one that shows how experimental detail matters, and how even long-standing claims can be wrong.
Videos demonstrating the correct reproduction of Newton’s two-prism experiment can be found under “Newton’s Two Prism Experiment – MITK12Videos”.
