James Clerk Maxwell (1831 – 1879) was a British scientist famous for his mathematical synthesis of the forces of electricity and magnetism into what is now known as the electromagnetic force. He is one of the most important figures in the history of physics.
Maxwell was born in Dumfrieshire, Scotland where he received an early education from his mother until she passed away when Maxwell was eight. A short time later he was enrolled at Edinburgh Academy where he excelled in mathematics. In April of 1847 Maxwell’s uncle took him on a trip to the private laboratory of physicist William Nicol where he was captivated by the experiments and demonstrations he witnessed and was determined thereafter to become a physicist. He entered Cambridge University three years later, earned top honors in mathematics, and after graduating became a professor in King’s College, London.
It was during his time as a professor at King’s College that he began formulating his theory of electromagnetism. Electric fields changing in magnitude create a magnetic field. Additionally magnetic fields changing in magnitude creates an electric field. Thus these fields moving together as a wave can create a continuous chain of creating. Maxwell realized that he could combine both the magnetic and electric fields into a single electromagnetic field through a series of equations, which we now refer to as the Maxwell equations. When Maxwell calculated the speed of these waves he obtained 186,000 miles per second, and so in 1864 he was able to conclude that light consists of electromagnetic waves. Eventually it was realized that light consists of only a small portion of the electromagnetic wave field with longer and shorter wave lengths being possible, eventually leading to discoveries such as radio waves and x-rays.
Maxwell also did other important work in optics. He presented the first color image in photography during a lecture in 1861, the same year he was elected the the Royal Society of London. In 1874 he was appointed director of the Cavendish Laboratory. However he did not hold this position long as he died five years later at the age of 48 due to stomach cancer. Even though his life was cut short his accomplishments and contributions to science were immense.
The battery has revolutionized the way we live, producing a reliable and portable power source for a wide range of products. The concept of batteries has a rich history that spans centuries, possibly even millennia. As far back as the 1st century AD, civilizations may have been experimenting with battery concepts, with artifacts discovered around Baghdad that resemble battery-like devices. However, the true purpose of these devices remains controversial.
Alessandro Volta and the Birth of the Battery
A Voltaic Pile
At the turn of the 19th century electricity was becoming an increasing topic of study. People were finding various ways to produce or store electric current but there was as of yet no way to produce a continuous flow of electricity.
In 1799 the Italian physicist Alessandro Volta solved this problem and first reported his findings in a letter to the Royal Society in 1800. Called a Voltaic pile, Volta stacked zinc, copper, and brine-soaked paper in layer after later, sometimes referred to as a voltaic cell. Adding a wire to both ends produced an electric current, with additional layers creating a stronger current. These additional layers stacked on top of each other created the voltaic pile. Volta realized that somehow the piles of metal disks were producing the current, an effect called an electromotive force.
In 1810 Humphry Davy showed that it was the chemical reaction between the two metals (electrode) and the liquid solution (electrolyte). Various difference metals and solutions can be used all to create an electromotive force.
The voltaic pile marked a significant milestone in the history of electricity. It was the first true electric battery, setting the stage for the development of modern batteries.
Unleashing the Power of Chemical Energy
A battery is then a chemical means of generating electricity. It works through a “redox” reaction, which is the process of reduction (one substance gaining electrons) and the process of oxidation (one substance losing electrons) occurring simultaneously. To perform the redox reaction most batteries consist of two electrodes – an anode (negative electrode) and a cathode (positive electrode) – separated by an electrolyte, which is a conductive material. The electrodes are typically made of two different materials, and the electrolyte allows ions to flow between them while preventing contact. When the battery is connected to an external circuit, the redox chemical reaction occurs within the battery, producing the flow of electrons from the anode to the cathode, creating an electrical current that can be used to power devices.
Volta’s battery is called a wet battery. While it did produce a controlled, continuous flow of electric current it was not very practical. There were significant limitations with its capacity, size, and portability. The battery was a large and cumbersome device and had a low energy density compared to modern batteries. What it was however, was a groundbreaking invention that paved the way for further development of battery technology. It was not until a dry battery was invented, which replaced the liquid electrolyte with a paste, that batteries portable and practical.
The Rise of Practical Batteries
The battery has undergone significant changes in the past two centuries since the invention of the voltaic cell. Here are a few notable improvements:
Daniell Cell: In 1836, the British scientist John Frederic Deniell invented a new cell using copper sulfate and zinc sulfate, separated by a porous pot, to create a longer-lasting source of power.
Lead-Acid Batteries: In 1859 the French physicist Gaston Plante invented the first rechargeable battery.
Leclanche Cell: In 1866, the French engineer Georges Leclanche patented a new kind of battery – a predecessor to the modern dry cell battery. It used a zinc anode and a manganese dioxide cathode wrapped in a porous material, dipped in a jar of ammonium chloride.
Nickel-Cadmium Batteries: In 1899 the Swedish inventory Waldemar Jungner invented the first alkaline battery.
Lithium-ion Batteries: Lithium is the metal with the greatest electrochemical potential. These batteries did not come to market until the 1970s and offer the highest densities and can hold its charge for the longest period of any battery.
A Modern Electric Vehicle Battery System (Credit: aec.org)
Peering into the future batteries will increasingly play a role in society. Emerging technologies such as artificial intelligence (AI), renewable energy storage, advanced portable devices, and electric vehicles (EVs) will need powerful batteries to conveniently function. As a result many of these industries are investing heavily in battery technology. Improved battery technology will enable the widespread adoption of many of these technologies, removing their limitations and making the more appealing to consumers.
Benjamin Franklin (1706 – 1790) achieved much in his life as a scientist, while still having time for success in business as a profitable entrepreneur in printing and writing, an innovative investor, a statesman critical in forming legislation for a new nation, a diplomat allowing a new nation to form, a philanthropist with an eye to be benefit of future generations, and above all – a visionary. Due to his wide range of extraordinary abilities he is one of the most accomplished and remarkable men in American history.
Ben Franklin was born in Boston and at an early age fell in love with reading. At age 12 he began an apprenticeship to his brother James, a printer, where he learned the printing trade. After five years he fled to Philadelphia looking for a new beginning to life and shortly after arrival in the city he quickly relocated to London on a promise from the Pennsylvania Governor that he could get some equipment to start a newspaper. When the promise fell through he returned to Philadelphia and founded The Pennsylvania Gazette. He continued to have success as an author when he published Poor Richard’s Almanack, a publication covering various topics which he continued for 26 years.
By the age of 42 Franklin was wealthy enough to retire from the printing business, where he became a gentlemen and began to engage in the curiosities of the day. This was the beginning of his short, but important time in life as a scientist and inventor. Some of his more famous inventions were the Franklin stove and the bifocal glasses, but his most famous scientific work is in electricity. The kite experiment that Franklin is supposed to have carried out was used to prove the lightning and electricity are the same phenomenon. This led to the invention of the lightning rod placed on buildings used to prevent fires.
As events in the American colonies continued to advance towards revolution Franklin eventually gave up his scientific inquiries and devoted the remainder of his life to being a politician, statesmen, and eventually a peacemaker. He was one of the founding fathers of the United States and played critical roles in shaping its destiny.
