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Santiago Ramón y Cajal

• Santiago Ramón y Cajal, a Nobel Prize-winning neuroscientist, used microscopes to study the nervous system.
• He discovered that the nervous system is composed of independent cells that communicate.
• Born in northern Spain, Ramón y Cajal was a rebellious child with a passion for drawing.
• His father, a doctor and anatomy teacher, persuaded him to attend medical school.
• Cajal's artistic talents combined perfectly with his scientific interests in the fast-developing field of neuroscience.
• Cajal used a microscope for the first time while training to become a doctor.
• He used his savings to buy his own and observed and drew muscle tissue structures on an increasingly small scale.
• He received a better microscope in 1885 where his work became focused on histology/anatomy at the microscopic level and commenced nervous system investigations.
• Microscope use for nervous tissue examination was limited before the 1870s due to low magnification and poor resolution.
• Advances in optical lenses and better tissue stains improved cell visibility.
• Cajal saw brain tissues stained using Golgi's tissue-staining technique while a professor of histology and pathological anatomy at the University of Barcelona in 1887.
• Having modified Golgi's tissue-staining technique, Cajal produced hundreds of illustrations of the human brain and nervous system.
• In 1887, seeing Camillo Golgi's method amazed Cajal, marking a career-changing event.
• Cajal later wrote that the nerve endings were visible, so he improved Golgi's method until nerve cells in the brain, eye and spinal cord of embryonic creatures were completely visible
• He hand-drew the cells seen through his microscope with detail, creating scientific illustrations.

Neuron Doctrine

• Cajal continued his modified staining technique on nervous tissue from different animals for six years.
• He observed in 1889 that the brain and nervous system contain billions of nerve cells that communicate through electrical and chemical transmission across synapses.
• Cajal's observations went against the reticular theory: nerve fibers were fused to form a continuous network
• Wilhelm Waldeyer, a German anatomist, coined "neuron" to mean nerve cell and supported Cajal's "neuron doctrine" stating that the nervous system's basic units are discrete cells (neurons) with connectivity determining function.
• The neuron doctrine replaced the reticular theory by the end of the 19th century.
• The neuron doctrine was widely accepted in the 1950s, when electron microscope images revealed synapses' existence.
• Cajal and Golgi were jointly awarded the Nobel Prize in Medicine or Physiology in 1906 for their studies on the nervous system; Golgi insisted that nerve cells were physically connected.

Max Planck

• Max Planck's quantum theory altered scientists' interpretation of the subatomic level, refuting traditional physics.
• Energy isn't emitted continuously; it comes in fixed packets called "quanta."
• Born in Kiel, Germany, Max Planck was the youngest of six children.
• Planck showed an aptitude for mechanics, mathematics, and music at the Maximilian gymnasium.
• He chose to study physics in college due to his interest being sparked by a tutor.
• At 21, he received a doctoral degree in 1879 from the University of Munich after submitting a thesis on thermodynamics.
• In 1889, Planck became professor of theoretical physics at the University of Berlin, where he stayed until his retirement in 1926.

Black Body Radiation

• The physicists of the 1890s were focused on "black body" radiation to explain the absorption and emission of light..
• In 1859, Gustav Kirchhoff defined it as an electromagnetic radiation absorber.
• Black body radiation was a hypothetical body that absorbs all electromagnetic radiation, including light, that falls on it.
• When heated, it radiates energy as electromagnetic waves with wavelengths of visible, ultraviolet, and infrared light.
• However, hot object wavelengths do not match traditional thermodynamic predictions.
• In 1894, Planck focused on black body radiation in Berlin, to match theory with observation.
• Planck showed support towards Albert Einstein in Germany, and created a professorship for him at the University of Berlin in 1914.

Planck's constant

• Atoms do not vibrate continuously at any frequency but only at whole-number multiples of a base frequency.
• He calculated the value of h, Planck's constant which is a fundamental physical constant with the same numerical value everywhere in the known universe..
• Photons (light particles) do not emit energy in a smooth wave with measured quantums.
• The quantum is the smallest packet of energy and stems for the Latin quantum, meaning "how much".

Planck's Radiation Law

• Planck's radiation law explained that the temperature of an object related to energy in electro radiation.
• With his equation, the energy (E) in a photon equals its electromagnetic radiation frequency (v) multiplied by Planck's constant (h). (E = hv)
• Planck presented light as packets to the German Physical Society in 1900, overturning physical theory, beginning a revolution in physics, & today is the origin of quantum theory.
• Albert Einstein confirmed Planck's hypothesis in 1905 when he extended it to explain photoelectric effect & the existence of discrete energy packets during light transmission.
• Defining his constant h allowed Planck to measure the Planck length which is the smallest measurement.
• The smallest measurable unit of time is 5 x 10^-43 seconds which refers to the time it takes for a photon to travel at light speed.

Nettie Stevens

• Nettie Stevens made the discovery that an animal's sex is determined by particular chromosomes.
• She was among the first women to have her contributions to genetics recognized.
• In 1900, Stevens graduated from Stanford University with a master’s in biology and earned a doctorate at Bryn Mawr College in 1903.
• Although her scientific career did not begin until she was 39, Stevens is credited today for her vital breakthrough in early genetics.

Sex Determination

• Scientists had divided opinions on how biological sex was determined at the beginning of the 20th century.
• Stevens's research on the chromosomal behavior of mealworms ended the debate that external factors, such as nutrition or temperature, were the cause.
• Her study noted that male reproductive cells contained both X and Y chromosomes, while female cells only had X chromosomes.
• She concluded the organism's sex was controlled by the chromosomes its parents passed down and she published in 1905.
• Her research made the connection between physical traits and chromosomes, the discovery was not widely acknowledged until after death.

George Washington Carver

• African American agriculturalist George Washington Carver helped boost South by improving nutrient depleted soil and using crops instead of cotton.
• He developed commercially viable products that could be derived from crops grown instead of cotton.
• Carver pursued an education following the abolition of slavery in 1865.
• After earning a master's degree in agriculture in 1896, he was made director of agriculture at the Tuskegee Institute.
• Carver later improved southern agriculture.

Restoring the Economy

• In the Southern US main crop in the late 19th century was cotton, the land was depleted of vital resources
• Carver pushed farmers to grow nitrogen-rich crops like peanuts, sweet potatoes, soybeans to replenish the soil help improve soil.
• Creating 400 usable marketable products like oils, dyes from alternative crops, Carver boosted the South & saw them become part of the American agricultural industry.

Thomas Hunt Morgan

• US geneticist and zoologist, Thomas Hunt Morgan, won a Nobel Prize for his work on heredity and chromosomes related to genetics.
• Morgan was born to a wealthy family in Kentucky in 1866 and was fascinated with the natural world.
• He was just 16 years old when Morgan attended the University of Kentucky to study sciences and carried postgraduate work in morphology and physiology.
• By 1890, Morgan had gained his PhD in zoology where he later combined teaching with research into embryology.
• Morgan made advances during his tenure at Bryn Mawr before receiving lasting fame through genetics later on.

Inheritance

• Morgan took up the role of professor in New York at Columbia University in 1904 to begin his work in heredity.
• Research was initially held in inherited characteristics, but it had been inconclusive/partial.
• Gregor Mendel theorized about genetics after studying qualities in pea plants in 1866.
• Morgan questioned much & favored controlled experiments to understand heredity.

Fly Room

• His experiments used Drosophila or fruit flies which had a wide range of traits, and had fewer chromosomes carrying genetic information, also reproduced at great speed.
• In 1908, Morgan set up a Columbia lab, known as the "Fly Room" where with partners he breds millions of the flies.
• Key discovery came when white eyed male fly was bred with red eyed female.
• Offspring had red eyes, indicating recessive whiteness.
• By breeding these offspring, 1 in 4 in the 2nd generation offspring had white eyes due to the white eye male breeding.

Sex Chromosome traits

• This showed that the white-eyed trait connected to the sex of the fly.
• Experiments show physical/sex linked traits being the determinant sex factor and chromosome.
• Males are X & Y while females are XX.
• Morgan deduced white eyes/traits are seen only in males being carried on the Y sex chromosome, genes occupying chromosome location & producing genetic maps.
• Through fly experiments, Morgan said the chromosomal inheritance theory and Mendel value are accurate, applying plants animals; Morgan shifted studies on the inheritance topic, launching genetics research in the field.

Marie Curie

• Marie Curie was a pioneer and scientist who discovered more about radioactivity.
• Curie discovered elements and helped with the use of radiotherapies for cancer.
• In Warsaw, Poland Maria Skłodowska life was difficult from a young age.
• Her mom and eldest sister died by the age of she was 10, and women were banned from attending college although she was bright.
• Marie studied secretly while working to make money for college.
• Meeting her husband while enrolled at Sorbonne college in Paris, she created a team with Pierre Curie as she met the physical elements.

Discoveries

• Fascinated by Henri Becquerel, curiosity led Curie to radium investigation & had Pierre join to research in this field.
• Working hard in the analysis of radium ore(pitchblende) the pair pinpointed radioactive elements of polonium and radium.
• Awarded with Becquerel for their findings, the Curie pair got the Nobel Prize in Physics in 1903.
• During the time of studying elements, Pierre abandoned personal research, joining Curies research, publishing landmark papers.
• The study of physics at Sorbonne opened after Pierre died, resulting in her second Nobel in 1911 for Chemistry, studying value & dangers of radioactivity.
• Curie coined "radioactivity" & was unaware of radiation side effects to disintegrating atoms of uranium samples in her desk.

Value & Danger

• Power of uranium rays & dangers of its other radioactive substances makes are harmful as Curie had dangerous radiation sickness.
• Scientists, discovered knowledge shared should'nt be for profit to help applications in medicine/science.
• They used winnings from award in fund of 20 mobile X-ray units, which is the French name for the littles Curie to the save wounded soldiers.
• Due to detrimental effects in over exposures scientist prove that, Curie, would die from anemia at an old age, a marrow issue, due to exposures.

Ernest Rutherford

• Ernest Rutherford transformed our understanding of the atom by researching the heart of matter and identifying its components.
• Elements, the existence of the gamma and beta radiation through the process.
• Rurtherford was from a farming background, winning a scholarship to Canterbury College.
• He graduated top for 3 degrees where he worked with physicist JJ Thomson & had a recommendation in Physics, leading to a professorship at the McGill University (1898) for age of 27.
• Working in what he discovered in Montreal he won a Nobel Prize.
• Henri Becquerel had just made discovered radioactivity and soon Thomson identified: a negatively charged subatomic particle, the electron Rutherford studied uranium-emitted radiation, calling them alpha/beta radiation.

Models

• He showed that alpha radiation consisted of positively charged particles.
• First transmutation with Rutherford equipment that uses nitrogen molecules and oxygen.
• He broke the machine, touching "ghost matter".
• Studying the degree of which "black body" electro radiation, light, hung up to the body he saw his Nobel.
• At the period scientists have been theorized sources or radiation is the source the frequency.
• By 1899 Planck had discovered the only at most atoms had the potential to vibrate a bases that multiplied by the atomic number for the element is “h".
• As an exampole, atoms could vibrate at at most the number 10 only.

Nuclear Power

• One-dimensional atoms was given it all this constant being used everywhere. By this, one can expect that the photons are only being pushed and manipulated and not given other choices to exist.
• E=hv is equal constant.
• Given this and presenting in Germany, the quantized physical physical society theory and initiation of new research in Physics, in the 1900s and 1905 by einstein and later the discovery of the light.
• With this, his value that, and this constant to the lowest unit measurement with the use is equal 1.6 times negative 35 power while for the measure is five times it by for and negative while for the measure is five times negative 43 power.
• In this is stated that most of the fundamental 20th-century scientific studies.

Rutherford - In the Atom

• Atoms became smaller releasing electrons by byproduct of its process and rates predictable was how half could be predicted.
• In the United Kingdom that he is also to perform other tasks such that he was to be the face of the University of Manchester.
• At the point, he introduced, the plum of this being the positive charge electron is at the thin layers of its side the atoms will albeit being not deflected.
• For what at the central will, in the 1911 he published as being all in one place.
• 1n 1919 came the succeeding and he would eventually be known for particles and all of the side actions.

Nettie Stevens

• Female biologist Nettie Stevens discovered animal's sex chromosomes
• Female scientists have had contributions recognized, but were overlooked
• Graduated from Stanford with masters in 1900, & from Bryn Mawr College in 1903 when she was 39 but later had vital breakthroughs.

Sex Chromosomes

• At the time, opinion split into biological sex determination in the 20th century
• Stevens' analysis of mealworms found sex was not nutrition/temperature
• Male reproductive cells had x/y chromosomes and is the cause of biological sex
• Her chromosomal analysis linked traits of certain organisms
• This chromosome knowledge not known until after death

G. Washington Carver

• African American Agricultural Scientist GW Carver boosts South using new science.
• Soil improvement, cultivation & crop development for financial gain by his hands
• Following years of educating, the Tuskegee Institute got the new agricultural scientist and director, GW Carver, as the head
• Carver worked to fix southern agriculture.

Restoration projects

• He was in charge with the task to reverse all damage done by the previous agricultural practices in South.
• Working with alternative crops like potatoes & soybeans to make soil better for farmers, he also created tons of alternate options for financial independence
• GW Carver and his team made many products for agriculture and saw the South grow from it.