The Pangea Puzzle, Ice Halos, & Raindrops: The Influence of Alfred Wegener

Ever since the continents were all mapped, people had noticed that many coastlines, like those of South America and Africa, looked as though they would fit together if they could be moved like puzzle pieces.

Alfred WegenerWith his revised publication of The Origin of Continents and Oceans in 1915 (originally published three years prior), Alfred Wegener was one of the first to suggest continental drift and plate tectonics. In his work, he described a ‘super-continent’ he called Pangaea had existed in the past, broke up starting 200 million years ago, and that the “pieces drifted” to their present positions. Citing similar ancient climates, rock structures, and fossil evidence.  [ Frank Taylor, an American scientist, had published a similar theory in 1910 but his work attracted little attention. ]

When continental drift was first proposed by Alfred Wegener in the early 1900s however, it was met with skepticism by the scientific community. The proposal remained controversial until the 1960s, when it became widely accepted over a fairly short period of time. Today, the theory of plate tectonics is key to the study of geology.

However, Wegener is not only the father of the theory of continental drift, he was also the first to describe the process by which most raindrops form. This process is now called the Wegener-Bergeron-Findeisen procedure.

The Pangea Puzzle, Ice Halos, & Raindrops: The Influence of Alfred Wegener @EvaVarga.net

Photo by Greg Clements (Field Studies in Greenland)

During Wegener’s lifetime the process by which cloud particles reach raindrop size was not known, but there was some idea how much rain, even during summer, began as snow in the clouds. In 1784, Benjamin Franklin had suggested this, and in 1904, Wilson A. Bentley, who spent a lifetime studying snow crystals and raindrops, found supporting evidence for the conjecture.

“Perhaps the only thing that saves science is the presence of mavericks in every generation.” ~ Alfred Wegener

In his 1911 publication, The Thermodynamics of the Atmosphere, Wegener noted that ice crystals invariably grow at the expense of super-cooled droplets because the crystals have a lower equilibrium vapor pressure. He then suggested that raindrops might result from this competition between ice crystals and super-cooled cloud droplets. Read more in the article Introducing Precipitation from the Eyewitness Companions: Weather from DK Publishing.

Wegener had hoped to document this process in real clouds, but other projects intervened and he never returned to the subject. Thus, it was left to Tor Bergeron and W. Findeisen to develop and prove the theory in the 1930s.

He also explained two rare ice crystal halo arcs that bear his name as well. Ice crystals often form in the frigid air just above the Greenland ice cap and can produce spectacular halos. In a 1926 article, Wegener explained two relatively rare arcs that appear opposite the sun and are now named in his honor.

Biography

The Pangea Puzzle: The Impact of Alfred Wegener @EvaVarga.netBorn in Berlin on November 1st, 1880, Alfred Wegener, was a German climatologist and geophysicist.

From an early age he took an interest in Greenland. He studied in Germany and Austria, receiving his PhD in astronomy in 1904. No sooner did he finish his dissertation than he dropped astronomy to study meteorology, the new science of weather.

At a time when the conquest of the North and South Pole began to enjoy enormous international public attention, Wegener made his first expedition to Greenland as the official meteorologist on a two-year Danish expedition in 1906.

Wegener experimented with kites and balloons, pioneering the use of balloons to track air circulation. That same year, he and his brother Kurt set a world record in an international balloon contest, flying 52 hours straight. When he returned he took up teaching meteorology at the University of Marburg.

He was the first to use kites and tethered balloons to study the polar atmosphere.

His fourth and final expedition was in 1930 as the leader of a major Danish expedition to Greenland. He celebrated his fiftieth birthday on November 1, but shortly afterwards the team got separated, and he was lost in a blizzard. His body was found halfway between the two camps.

The Pangea Puzzle: The Influence of Alfred Wegener @EvaVarga.netBring it Home

Science MilestonesVisit my Science Milestones page to learn more about scientists whose discoveries and advancements have made a significant difference in our lives or who have advanced our understanding of the world around us.

The Father of Genetics: Gregor Mendel

When my son was diagnosed with congenital nystagmus as an infant, I became increasingly interested in heredity or the passing of phenotypic traits from parents to their offspring. Both my brothers also have nystagmus and it was now clear that I carry the gene as does my daughter.

The Father of Genetics, Gregor Mendel @EvaVarga.net

This post contains affiliate links.

Nystagmus is inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two copies of the X chromosome), one altered copy of the gene in each cell can cause the condition, although affected females may experience less severe symptoms than affected males.

Genetics is the study of genes, heredity, and genetic variation in living organisms.

Single gene inheritance is also referred to as Mendelian inheritance as it follows transmission patterns Gregor Mendel, a late 19th-century scientist and Augustinian friar, observed in his research on peas. As a result of his work, he is known as the Father of Genetics.

Mendel studied ‘trait inheritance’ or how different traits are passed on from parents to their children. He observed that organisms (pea plants) inherit traits by way of discrete “units of inheritance”. This term is a somewhat ambiguous definition of what is referred to today as a gene.

The four types of Mendelian inheritance patterns he described include:

Autosomal: the gene responsible for the phenotype is located on one of the 22 pairs of autosomes (non-sex determining chromosomes).

X-linked: the gene that encodes for the trait is located on the X chromosome.

Dominant: conditions that are manifest in heterozygotes (individuals with just one copy of the mutant allele).

Recessive: conditions are only manifest in individuals who have two copies of the mutant allele (are homozygous).

Biography

The Father of Genetics, Gregor Mendel @EvaVarga.netJohann Mendel was born July 20, 1822, in Heinzendorf bei Odrau, a small village in the Czech Republic (formerly the Austrian Empire). His parents were small farmers who made financial sacrifices to pay for his education.

He entered the University of Olomouc in 1840. He took courses in physics, mathematics and philosophy. He was advised by a professor to join the Abbey of St. Thomas in Brünn as a monk when he was 21 years of age to help offset the cost of his education.

The Abbey actually had a good reputation for its teaching of sciences, and its director, Abbot Franz Cyril Napp, was particularly interested in heredity of traits in plants and animals on farms. Upon joining the Abbey, he took the name Gregor.

My scientific studies have afforded me great satisfaction; and I am convinced that it will not be long before the whole world acknowledges the results of my work.  ~ Gregor Mendel

After completing his studies, he returned to the monastery in 1854 and took a position as a physics teacher at a school at Brünn, where he taught for the next 16 years. The monastery had a 5 acre garden, and two former professors encouraged Mendel to pursue his interest in heredity by using the garden for experiments.

Mendel set himself the very ambitious task of discovering the laws of heredity. To achieve this, he embarked on a highly systematic, eight year study of edible peas, individually and carefully recording the traits shown by every plant in successive generations. His work involved growing and recording the traits in about 30,000 plants.

One of the keys to his success was breeding from closely related pea varieties which would differ in only a small number of traits. The seven traits of pea plants that Mendel chose to study: seed wrinkles; seed color; seed-coat color, which leads to flower color; pod shape; pod color; flower location; and plant height.

In 1866, he published his heredity work, though it was not immediately recognized for the wealth of information it contained.

Bring it Home

? Explore genetics in more depth with a Genetics Unit Bundle from Amy Brown.

? Use M&M’s to visually see the genetic probability that an offspring will carry a certain trait. Just don’t each them all before you finish!

? Explore the genetics of sickle cell disease through Punnett squares, pedigrees, and an optional chi-square analysis with this classroom activity from the Howard Hughes Medical Institute.

? Enjoy this 3-D animation, available in both basic and advanced detail, which depicts the molecular machinery responsible for quickly and accurately copying DNA.

? Here is a cute video of an interview with Gregor Mendel from Untamed Science.

? Download the free printables from Stephanie Harrington and enjoy the book Gregor Mendel: The Friar Who Grew Peas.

? Create a DNA model of your own using pipe cleaners and beads or if you prefer, Lego bricks.

? Erect a DNA Double Helix Table Sculpture Puzzle

? If you still have those M&Ms, consider this Easter egg and M&M genetics activity from All Things Beautiful!

Science Milestones

Visit my Science Milestones page to learn more about scientists whose discoveries and advancements have made a significant difference in our lives or who have advanced our understanding of the world around us.

The bloggers of the iHomeschool Network have teamed up to create fun and original unit studies on fascinating people who were born in July.

The Silent Killer: Ecology Lessons with Rachel Carson

Ecology Lessons with Rachel Carson @EvaVarga.netThis post contains affiliate links.

Marine biologist and author Rachel Carson, whose writing on pesticides helped to launch the modern environmental movement, was born on 27th of May in 1907 in Springdale, Pennsylvania. Carson published her famous work Silent Spring in 1962 which documented the dangers of indiscriminate use of synthetic pesticides, especially on bird populations. Though its publication was met with strong opposition from the chemical industry, the scientific community largely supported her conclusions. Silent Spring also served as a rallying point for the young environment movement just gaining momentum at the time of its publication.

In nature nothing exists alone.

The book fueled public interest in environmental and public health issues and, within a few years, the Nixon Administration formed the Environmental Protection Agency. Much of the EPA’s early work focused on issues raised by Carson’s work such as a 1972 law regulating pesticides and a US ban on the agricultural use of DDT.

Biography

Rachel CarsonRachel grew up in a tiny, wooden house with no electricity, heat or plumbing. As a young girl, she was fascinated with the outside world. She spent a great deal of time in the woods and beside streams learning the names of birds, insects, and flowers.

Rachel’s best friend was her mother, Maria Carson, with whom she enjoyed taking long walks with in their nearby woods. Maria had been a teacher before she married and she taught Rachel the names of plants, birds, insects, and animals they encountered. It didn’t take long before Rachel was able to identify dozens of wild things.

Those who contemplate the beauty of the earth find resources of strength that will endure as long as life lasts.

In Rachel’s second year of college, she took a biology course that sparked her interest in this area. She graduated from college with honors and decided to specialize in Marine Biology- the study of animal life in the ocean. In 1929, she won a full scholarship to John Hopkins University in Baltimore, Maryland to obtain her graduate degree in this field of study.

After graduating from Johns Hopkins in 1932 (MA in Zoology), she began a career in the federal service as a scientist and editor and rose to become Editor-in-Chief of all publications for the U. S. Fish and Wildlife Service.

In addition to the well known Silent Spring, she wrote several other articles designed to teach people about the wonder and beauty of the living world, including “Help Your Child to Wonder,” (1956) and “Our Ever-Changing Shore” (1957). Woven throughout her writing was the view that human beings were but one part of nature distinguished primarily by their power to alter it, in some cases irreversibly.

Man is a part of nature, and his war against nature is inevitably a war against himself.

Rachel Carson died in 1964 after a long battle against breast cancer. Her witness for the beauty and integrity of life continues to inspire new generations to protect the living world and all its creatures.

Ecology Lessons with Rachel Carson @EvaVarga.netBring It Home

With Rachel Carson as a guide, students can learn how environmental concerns affect their lives and community. High students should be encouraged to read Silent Spring. Middle school students may be more comfortable reading selected chapters; I recommend the first chapter “A Fable for Tomorrow,” which can be previewed online. [Tip: Do a search on the chapter title to find the full text, which is available from various sources.]

  • Read a biography:
  • Watch the compelling documentary film American Experience: Rachel Carson’s Silent Spring
  • Have the students write a short story about how they think the world will change in the next ten years.
  • Ask students how they perceive our oceans being polluted today and let them come up with ways we can contribute to the efforts of protecting our sea life.
  • Have students research the toxic effects of DDT on the body, where it might be used today, and what alternatives can be used in its place.
  • Ask students to make a booklet on ways to live that can reduce an individual’s impact on the environment. Examples of subjects include saving water, gardening, cleaning and maintenance around the house, your car, renewable energy, air pollution, and the environmentally aware consumer.
  • Interview a person who has lived in the community for 30 years or longer. Suggested questions might include:
    • How has our community’s environment changed over the time you have lived here?
    • What was the environment of our community like when you first lived here?
    • What changes made the greatest impact on the environment?
    • Have the changes been for the better? Why do you feel this way?
    • In retrospect, compare the benefits and detriments of the impact of people on the land.

What about us? Can we avoid the “silent spring” that Carson predicted? In the 53 years since Silent Spring first appeared, people have grown far more aware of our impact on the environment. But we still use many potentially deadly chemicals.”There remains, in this space-age universe,” wrote Rachel Carson, “the possibility that man’s way is not always best.” We would do well to remember her warning.

Science Milestones

Science Milestones: Mendeleev & The Periodic Table of Elements

Creating what is arguably the most iconic symbol ever seen in science, Dmitri Mendeleev was passionate about chemistry. He was also an educator and his deepest wish was to find a better way of organizing the subject. Mendeleev’s wish led to his discovery of the periodic law and his creation of the periodic table.

mendeleev

Biography

Dmitri Ivanovich Mendeleev was born February 8, 1834 in Verkhnie Aremzyani, in the Russian province of Siberia. He was the youngest of at least 16 children. He first trained to be a teacher like his father, winning a place at his father’s old college. He continued his studies at St. Petersburg and graduated in 1856 with a master’s degree in chemistry. In 1863 Mendeleev was appointed to a professorship and in 1866 he succeeded to the Chair in the University.

Mendeleev is best known for his work on the periodic table; arranging the 63 known elements into a Periodic Table based on atomic mass, which he published in Principles of Chemistry in 1869. His first Periodic Table was compiled on the basis of arranging the elements in ascending order of atomic weight and grouping them by similarity of properties.  He predicted the existence and properties of new elements and pointed out accepted atomic weights that were in error. His table did not include any of the Noble Gases, however, which had not yet been discovered.

“In a dream I saw a table where all the elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper.”

As new elements that he had predicted were discovered, Mendeleev’s fame and scientific reputation were solidified. In 1905, the British Royal Society gave him its highest honor, the Copley Medal. In the same year he was elected to the Royal Swedish Academy of Sciences. Element 101 is named Mendelevium in his honor. He died two years later of influenza.

mendeleevBring it Home

Science Milestones

To learn more about those born in the month of February, visit the iHomeschool Network’s Birthday Lessons.

 

Science Milestones: Linus Pauling & Molecular Medicine

As an Oregon State University alum, Linus Pauling’s memory invokes a sense of pride. Not only was he one of the greatest scientists of our modern age, but he was also a much respected and beloved defender of civil liberties and health issues.

My father, when I had just about reached my ninth birthday, wrote a letter to the Portland Oregonian, asking for advice as to what books to get for me. He said that I seemed to have an unusual interest in reading, especially history. Then he went on to say, “And don’t say the Bible and Darwin’s Origin of Species, because he has already read them.”

linuspauling

Biography

Linus Carl Pauling was born in Portland, Oregon, on February 28, 1901. He received his early education in Oregon, finishing in 1922 with a bachelor’s degree in chemical engineering from Oregon Agricultural College in Corvallis — now Oregon State University. Already he was drawn to the challenge of how and why particular atoms form bonds with each other to create molecules with unique structures.

LinusPaulingFor postgraduate study Pauling went to the California Institute of Technology (Caltech), which provided a stipend for research and teaching. In 1925 he received a Ph.D. in chemistry and mathematical physics. Awarded a Guggenheim Fellowship, in 1926-27 he studied in Europe with physicists who were exploring the implications of quantum mechanics for atomic structure. In this revolutionary new field Pauling found a physical and mathematical framework for his own future theories regarding molecular structure and its correlation with chemical properties and function.

Pauling discovered that in many cases the type of bonding — whether ionic or covalent (formed by a sharing of electrons between bonded atoms) — could be determined from a substance’s magnetic properties. To explain covalent bonding, Pauling introduced two major new concepts, based on quantum mechanics: bond-orbital hybridization and bond resonance.

Pauling originated the concept of molecular disease. In 1945, while hearing a physician describe sickle cell anemia, he instantly surmised that it might be caused by a defect in the red blood cell’s hemoglobin. After three years of painstaking research, he and his associate Dr. Harvey Itano identified this prevalent disease as molecular in origin — caused by a genetically transmitted abnormality in the hemoglobin molecule.

“I have always liked working in some scientific direction that nobody else is working in.”

Pauling’s description of this first molecular disease initiated a search for many more such disorders. The new idea quickly became immensely important in medicine and is now the main focus of human genome research. Thus the medical specialties of hematology, serology, immunology, applied genetics, and pathology owe much to Pauling’s contributions, which were made long before his intense interest in the promise of nutritional therapy became widely known.

In 1954 Linus Pauling was awarded the Nobel Prize in Chemistry. Pauling put his elevated new position as a Nobel laureate to good effect in his growing social activism. In the late 1950s and early 1960s he protested vehemently against atmospheric nuclear testing.

Pauling’s antitesting campaign was vindicated when a treaty was signed by the three nuclear powers — the U.S., Great Britain, and the U.S.S.R. On October 10, 1963, the day on which the limited test ban went into effect, it was announced that Linus Pauling would be awarded the Nobel Peace Prize for 1962.

Linus Pauling is the only person to be awarded two unshared Nobel Prizes and one of only four individuals to have won more than one Nobel Prize (the others being Marie Curie, John Bardeen, and Frederick Sanger). Also of note, he and Marie Curie are the only people to be awarded Nobel Prizes in different fields.

Bring it Home

Science Milestones: The Golden Gate Bridge

One of the seven wonders of the modern world, the Golden Gate Bridge was the life mission of an engineer who had never designed or overseen the building of a suspension bridge. At the time of its construction the Golden Gate Bridge was the longest suspension bridge in the world, built hundreds of feet above the dangerously churning waters of the entrance to San Francisco Bay, the Golden Gate. 

goldengatebridgeJoseph Strauss, a bridge builder from Chicago, had been visiting San Francisco for several years to supervise work on a small drawbridge, one of four hundred he had built around the world. But Strauss’s ambitions far surpassed any work his firm had ever attempted.

Bridges have long been an interest to us a family and we enjoy spending the weekend in the big city of San Francisco whenever possible. We watched the new Bay Bridge as it was constructed but the red hue of the Golden Gate Bridge has always captivated us.

Biography

straussJoseph Baermann Strauss was born in Cincinnati, Ohio on the 9th of January 1870. He loved poetry and hoped to pursue a career in the arts like his mother, a pianist, and his father, a painter and writer. Though he never became a fine artist, he would help create one of the most famous bridges in the world.

Following his college graduation, Strauss worked as a draftsman for the New Jersey Steel and Iron Company, and the Lassig Bridge and Iron Works Company in Chicago. Seven years later, he was named principal assistant engineer in the firm of Ralph Modjeski, a Chicago engineer. While working for Modjeski, Strauss developed his trademark “bascule” drawbridge design. Strauss’ bascule was a utilitarian structure, practical but unlovely.

Strauss eventually left Modjeski’s company, forming the Strauss Bascule Bridge Company in 1904. A prolific engineer, he constructed some 400 drawbridges across the U.S. Yet he dreamed of building “the biggest thing of its kind that a man could build.”

In 1919, San Francisco’s city engineer, Michael O’Shaughnessy, approached Strauss about bridging the Golden Gate, the narrow, turbulent passage where San Francisco Bay meets the Pacific Ocean. Strauss campaigned tirelessly over the next decade to build the bridge. He faced enormous opposition from the “Old Guard” — environmentalists, ferry operators, city administrators, and even the engineering community. Yet in November 1930, a year into the Great Depression, voters at last supported a bond issue for Strauss’ bridge. The ambitious project finally had its green light.

Strauss alienated many people in his quest to build the structure, his first suspension bridge. Obsessed with claiming credit as the span’s creator, he minimized the contributions of Charles Ellis and Leon Moissieff, the two visionaries who actually worked out the significant engineering challenges of building the bridge.

On May 27, 1937, the bridge opened to the public. Returning to his other great love, poetry, Strauss composed verse for the occasion, exulting, “At last, the mighty task is done.” It would be the last mighty task of his life. Exhausted, Strauss moved to Arizona to recover. Within a year, he would die of a stroke.

Bring it Home

  • Read about some of the opposition to the bridge. Then prepare a poster expressing either support for, or opposition to, the Golden Gate Bridge project. Your poster should reflect one of the arguments made for or against the bridge at the time it was being debated. Illustrate your poster with a drawing of the benefit or harm the bridge would bring to your community.
  • During his campaign, Strauss had bribes distributed to members of the San Francisco Board of Supervisors to secure their support for the project. Imagine that you are a young newspaper editor in San Francisco at the time and you have just learned about these bribes. How could you respond in a way that would be in the city’s long-term interest? Write an editorial condemning the bribes or praise the project as necessary regardless of the maneuvers that might be necessary to make it happen.
  • Read about Irving Morrow, about the man who designed the Golden Gate Bridge’s distinctive Art Deco features. Find a photo of another building or other object designed in the Art Deco style and explain what you like about the style. Alternatively, choose another bridge or building structure, find out what style of architecture it represents, and explain why you like it.
  • Coordinate a toothpick bridge building competition amongst your friends.
  • People love suspension bridges for many reasons: their beauty, their utility, their mathematical elegance, their long spans, or even for the regional bragging rights they confer. Research other suspension bridges around the world and create a PowerPoint or a webpage to share with others what you learned.
  • Learn how the Golden Gate Bridge was financed. What is a bond? Why do governments issue bonds? Why do voters have to vote to approve a bond issue? What is “collateral” and what did these six counties use as collateral for the bonds?
  • Visit the Golden Gate Bridge and the Golden Gate Bridge Pavilion yourself and learn more about the construction of this Strauss’ first suspension bridge.
  • While in San San Francisco, enjoy the Golden Gate Treasure Hunt in honor of the 75th Anniversary.

Science Milestones