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Who invented the electron microscope?

The theory of the electron microscope was based on the work of Hermann von Helmholtz and Ernst Abbe, two physicists. They posited that there were wavelengths that were "smaller than light" and thereby invisible to the naked eye. This was the first theory of electrons.\n\nFollowing Abbe and von Helmholtz, a doctoral candidate named Louis de Broglie developed equations that would ultimately lead to the discovery of electron waves. He theorized that every particle produces an electron wave at a particular frequency.\n\nUsing magnetic lenses that direct electrons, these electron waves were ultimat..

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How does segregation affect people?

Segregation, according to some researchers, widens the gap between rich and poor. Populations of minorities, such as African Americans, reside primarily in inner city areas. Inner cities contain far fewer resources, such as healthcare facilities, schools and even grocery stores than urban areas. Limited access to education resulting from segregation produces negative impacts on minority groups. Without education and role models for success, students in poor areas see limited opportunities for careers and financial stability. Successful members of segregated populations often leave, further red..

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In what way were the Safavids different from the Ottomans?

The Safavid Empire began in the 13th century in Persia when the Safaviyya Sufi, led by Safi-ad-din Ardabili, became prominent. Safi-ad-din and his heirs unified Persia, then took over large regions stretching from Pakistan to Turkey. Under the Safavid Empire, Persia once again became the dominant link between the Eastern and Western trading worlds.\nBoth the Safavids and the Ottomans, as well as the Indian Mughals, were "gunpowder empires," using advanced gunpowder-based weaponry to expand their influence. Once the two empires came in contact, the Turks and Safavids fought over Iraq for over a..

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How did Anne Frank die?

After their arrest by the Gestapo on August 4, 1944, the Frank family lived briefly at Westerbork, a holding camp in the Netherlands. In September 1944, they were shipped via rail to the Auschwitz-Birkenau concentration camp in Poland. Edith Frank, Anne's mother, starved to death at Auschwitz. Anne and Margot were later transferred to Bergen-Belsen, which had regular and severe typhus outbreaks. Otto Frank, Anne's father, survived internment at Auschwitz and was rescued by Soviet forces on January 27, 1945.

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When did the Taliban take over Afghanistan?

The Taliban came to power in Afghanistan after the chaotic civil war that occurred following the collapse of the Soviet-supported regime in the early 1990s. With support from the Pakistani government and intelligence services, the Taliban defeated its enemies and secured control over the majority of Afghanistan. Establishing a capital at Kandahar, the Taliban began to impose a rigorous form of Islamic law, oppressing women and suppressing other faiths. The reign of the Taliban came to an end in 2001, when the United States attacked in response to its support for the Al-Qaeda terrorist group th..

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How did World War I change the way wars were fought?

The machine gun was a recently-developed weapon that had a significant effect on how World War I was fought. Its capability of shooting hundreds of bullets a minute at targets that were up to 4,000 yards away provided an advantage to the defenders' trenches. The attackers were quickly mowed down before they could reach the defenders' entrenched positions. In this way, the machine gun not only contributed to the mass slaughter that was characteristic of World War I trench warfare, it also created the need for the armored vehicles that could safely cross the area between the opposing t..

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How much did it cost to build the Biltmore House?

The Biltmore House is a 250-room mansion that was opened to the public in March 1930. It is currently one of the largest travel and tourism attractions in the mountains of Asheville. The family has added a winery, several restaurants and a conservatory, which draws close to 850,000 visitors each year. The estate covers over 8,000 acres with 75 acres of formal gardens and a 210-room hotel.

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What are some well-known cults in American history?

The People's Temple, which featured branches throughout California, met its end in the commune known as Jonestown in Guyana. Jones moved his operations from California there in the late 1970s due to media scrutiny over accusations that he abused cult members. Following a November 17 visit to Jonestown by Congressmen Leo Ryan, Jones had the representative and members of his group murdered. Jones forced his cult members to drink cyanide-laced juice.\nApplewhite convinced his followers of the Heaven's Gate movement that a spaceship following behind the Hale-Bopp comet would transport th..

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What were catapults used for?

Catapults could be built on top of a wheeled structure to provide mobility for the device if needed. They could be used for both defending and attacking, and were sometimes mounted on castle walls to defend against an enemy siege. Attackers would use catapults to weaken and destroy walls that could not be assaulted with typical weaponry. They would also use the catapults to set susceptible areas on fire with flammable projectiles.\nSeveral types of catapults existed, such as mangonels, ballistae and trebuchets. Mangonels were catapults that utilized force of torsion caused by twisting ropes an..

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Why was Italy the birthplace of the Renaissance?

The philosophy underlying the artistic, scientific and literary endeavors of the Renaissance was that of humanism, a system of thought that values human life and strives to achieve human goodness. Humanism was highly based on Classical values; the Greeks and Romans had stressed the importance of developing wisdom, virtue, economic abundance and physical well-being. Because the Italian city states were the direct descendants of the Romans, they had greater access to the works and writings of their progenitors.\nThe fall of Byzantium to the Ottoman Turks in the 15th century contributed to Italy&..

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