Famous Discoveries in Physics and Bacteriology

Study Notes

Wilhelm Conrad Röntgen

German physicist Wilhelm Conrad Röntgen discovered X-rays in 1895.
X-rays were discovered when Röntgen observed that electrically charged vacuum tubes emitted rays that made a fluorescent screen glow.
These electromagnetic rays can penetrate human skin to expose photographic plates but are blocked by metal and bone.
Röntgen was awarded the first Nobel Prize in Physics in 1901 for his discovery.
He bequeathed the prize money to scientific research and never patented the X-ray.
Röntgen is also known for his discoveries in mechanics, heat, and electricity.

Kitasato Shibasaburo

Japanese bacteriologist Kitasato Shibasaburo developed serum therapy to protect against tetanus and diphtheria.
In 1890, Kitasato discovered that injections of his tetanus serum, which contained the antitoxin produced in the blood of an animal exposed to the tetanus bacteria, conferred immunity on the animal to which it was given.
He applied the same principle to protect against diphtheria.

Ivan Pavlov

Russian physiologist Ivan Pavlov researched the digestive secretions of dogs.
Pavlov found that dogs learned to associate the arrival of food with the sound of a bell.
After a while, the dogs still salivated in response to the bell being rung even if no food was provided.
This is now called classical, or Pavlovian, conditioning.
Pavlov won the Nobel Prize in Physiology or Medicine for his work in 1904.

Jules Henri Poincare

Mathematical physicist Henri Poincaré investigated causes for changes in the solar system.
While trying to prove that the solar system is stable, Poincaré discovered that even tiny changes in initial conditions often result in large and unpredictable changes in outcome.
This is called chaotic behavior.
Poincaré's findings about chaos, published in 1908, were overlooked but became the foundation for chaos theory several decades later.
Poincaré also wrote papers on electromagnetism that informed Einstein's work on relativity.

J.J. Thomson

English physicist J.J. Thomson was one of the first scientists to describe the structure of atoms.
Thomson identified "corpuscles" (later called electrons) using a cathode ray tube.
These particles have a negative electric charge and are about 2,000 times lighter than a hydrogen atom.
In his plum pudding model, Thomson suggested that every atom consists of electrons and an amount of positive charge to balance their negative charges.
Thomson thought the positive charge was spread throughout the atom and the electrons existed within it.
His discovery revolutionized theories surrounding atoms and electricity.
He also confirmed the existence of isotopes - elements that each have several types of atoms, chemically identical but differing in weight.

Svante Arrhenius

Swedish physicist Svante Arrhenius studied physics at the University of Uppsala.
In the 1890s, Arrhenius linked human activity with rising global temperatures.
He suggested that past ice ages might have been caused by fewer volcanic eruptions, reducing the amount of gases such as carbon dioxide in the atmosphere.
Arrhenius argued that these gases retain heat, so reducing them would cool down Earth.
He noted that burning fossil fuels would increase these gases and make the Earth warm up.

Description

Explore the groundbreaking contributions of Wilhelm Conrad Röntgen and Kitasato Shibasaburo. Learn about Röntgen's discovery of X-rays and his impact on physics, alongside Kitasato's development of serum therapy for tetanus and diphtheria. This quiz covers key historical milestones in medical and physical sciences.