John Henry Poynting was more than just a Victorian scientist collecting data. He gave us language to describe the movement of energy. Born 9 September 1852 in Monton, Lancashire, died 30 March 1914 in Birmingham. However, his true heritage is not mentioned on his birth certificate. This is in the Poynting vector.
He spent his career at Mason Science College (later University of Birmingham). He taught physics there from 1880 until his death. That’s 34 years to teach, experiment and rewrite the rules.
In 1884 and 1885 he published papers that changed everything. We knew about electricity and magnetism before Poynting. There is no simple formula to explain how energy actually flows in the universe. he solved the problem. His theorem showed that the energy flow at any point can be calculated using only these two forces. This is called the Poynting vector. This is the basic concept of electromagnetism. Without this, our understanding of the movement of light, the passage of radio waves and the operation of antennas would be compromised.
He also studied radiation. He wrote a paper about light pressure. Sound abstract? it is not. This means that light can push objects. he proved it.
Then he became interested in the Earth itself. He spent 12 years doing experiments to calculate the average density of the earth. This continued until 1891. He did not stop there. In 1893, he determined the gravitational constant. This number represents the strength of gravity. This is a fundamental building block of physics.
In 1894, he published his findings in “The Average Density of the Earth”. Then in 1913 he published The Earth, Its Shape, Dimensions, Weight, and Rotation*. He wanted to know exactly what our planet is made of and how it moves.
The Poynting vector is still the usual way to describe the directed energy flow of an electromagnetic field.
Why is this important today? The Poynting vector is used every time the phone is started. The wireless signal sent from the tower to the device is controlled by the Poynting vector. He doesn’t just crunch numbers. He draws an invisible map.
he is a professor. he is a researcher. he is very accurate. But most importantly, he was clear. Now when you look at electromagnetic energy diagrams, you look at his work. It’s very simple. It is elegant. It’s everywhere.
