19th and 20th Century Scientific Advancements

19th and 20th Century Scientific Advancements

• Science became intimately linked with progress at the turn of the 19th century.
• Fundamental ideas were rewritten in the 20th century, at both subatomic and cosmological levels, due to discoveries.

Wilhelm Conrad Röntgen

• German physicist who made key advancements in physics and medicine.
• Discovered X-rays in 1895.
• Found electrically charged vacuum tubes emitted rays that made fluorescent screens glow.
• Electromagnetic rays passed through human skin, exposing photographic plates, but were blocked by metal and bone.
• Awarded the first Nobel Prize in Physics in 1901.

Ivan Pavlov

• Russian-born, abandoned religious career for a career in medicine.
• Became professor at Military Medical Academy, St. Petersburg.
• Was director of physiology department and researched digestive secretions of dogs.
• Discovered dogs learned to associate food with a bell's ring (classical/Pavlovian conditioning).
• Awarded the Nobel Prize in Physiology or Medicine in 1904.

Kitasato Shibasaburo

• Japanese physician and bacteriologist.
• Studied in Tokyo and Berlin, developed serum therapy to prevent tetanus and diphtheria.
• Discovered tetanus serum containing antitoxin produced from animal blood exposed to tetanus bacteria.
• Developed principle to protect against diphtheria.

J.J. Thomson

• English physicist who described the structure of atoms (one of the first).
• Identified "corpuscles" (later called electrons).
• Used cathode ray tubes to identify particles with negative electric charges.
• Suggested that every atom contains electrons and an amount of positive charge (plum pudding model).

Jules Henri Poincaré

• Mathematical physicist who noticed small initial changes lead to unpredictable outcomes (chaotic behavior).
• His work on chaos was key in developing chaos theory.

Svante Arrhenius

• Studied physics in Sweden, became professor at University of Stockholm.
• Suggested that past ice ages might have been caused by fewer volcanic eruptions causing gas buildup in the atmosphere, cooling the earth.
• Linked human activity with rising global temperatures (pioneering idea of climate change).

Annie Jump Cannon

• American astronomer, leading authority on star spectra in 20th century.
• Studied physics and astronomy at Wellesley College.
• Joined Harvard College Observatory to process astronomical data.
• Pioneered star classification system (Harvard Spectral Classification).
• Classified 350,000 stars over 44 years.

Henrietta Swan Leavitt

• Studied astronomy at Radcliffe College.
• Examined luminosities of stars from thousands of photographic plates at Harvard College Observatory.
• Discovered pattern of brightness in Cepheid variable stars (pulsating stars).
• Crucial for measuring distances between Earth and other galaxies.
• Discovered over 2,400 variable stars and 4 novae.
• Developed a standard for photographic measurements (Harvard Standard).

Harriet Brooks

• First female nuclear physicist in Canada.
• Studied under J.J. Thomson and Ernest Rutherford.
• Worked in Marie Curie's laboratory.
• Discovered that one element could change to another through nuclear decay.

Srinivasa Ramanujan

• Born in Madras, India.
• Significant contributor to mathematical analysis and number theory, despite limited formal training.
• Sent letter with 120 theorems to G.H. Hardy, leading to his work at Cambridge.
• Awarded Bachelor of Science degree in 1916.
• Second Indian to become a Fellow of the Royal Society.
• Died in 1920 from tuberculosis.

Erwin Schrödinger

• Studied physics at University of Vienna, then in Germany and Zurich (Switzerland).
• Developed wave equation in quantum physics, revolutionizing understanding of atomic particles.
• Rather than orbiting the nucleus, electrons are distributed in clouds of probabilities.
• His wave mechanics changed the way the world views atoms and quantum mechanics.

Ronald Fisher

• British statistician and geneticist.
• Pioneered application of statistics to scientific experimentation, publishing a paper in 1918.
• Reconciled apparent inconsistencies between Charles Darwin's natural selection and Gregor Mendel's experiments.

Harold Urey and Stanley Miller

• Investigated early Earth conditions in the lab.
• Simulated primitive atmosphere with water, hydrogen, methane, and ammonia.
• Used electrical sparks to mimic lightning.
• Showed how simple carbon-based compounds could form (precursors to life) under these conditions.

Other notable figures and advancements are discussed in different areas.

Explore the significant scientific advancements of the 19th and 20th centuries, focusing on key figures like Wilhelm Conrad Röntgen and Ivan Pavlov. Discover Röntgen's groundbreaking work on X-rays and Pavlov's revolutionary studies in classical conditioning. This quiz will test your knowledge on these pivotal moments in science.