In contrast to mechanical waves, electromagnetic waves can travel without a medium. This implies that electromagnetic waves can pass not only through solid objects like air and rock but also through empty space.
James Clerk Maxwell, a Scottish scientist, created a scientific theory to explain electromagnetic waves in the 1860s and 1870s. He realized that electromagnetic waves can be created when magnetic and electrical fields combine together. He compiled this electricity-magnetism relationship into what are now known as "Maxwell's Equations."
German physicist Heinrich Hertz used Maxwell's theories to explain how radio waves are transmitted and received. In honour of Heinrich Hertz, the hertz, or one cycle per second, is the unit of radio wave frequency. Two issues were resolved by his radio wave experiment. First, he had proven that the speed of radio waves was the same as the speed of light, which was something Maxwell had only theorized.
This demonstrated how radio waves are a type of light. Second, Hertz discovered how to create electromagnetic waves by causing the electric and magnetic fields to separate from wires.
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By first playing Italy, France and Britain against each other (they were trying to takeover Ethiopia), while this was happening, he built a large arsenal of modern weapons. When Italy advanced into Ethiopia, Menelik II declared war and successfully defeated the Italians and kept Ethiopia independent.
It didn't and it did. Just because the case happened in 1954 doesn't mean that schools ended segregation, as a matter of fact it lasted for almost a decade more, if not longer because schools would still refuse to obey. Southern communities were especially supportive of segregation, and even when the civil rights acts were implemented they still didn't support them and they didn't want to be around African-Americans only it had to be hidden. On the other hand, when a Supreme Court makes a decision it does sway people to support it. That is because there is an idea of everyone being equal in the eyes of law and the supreme court is the judge on what is lawful and what isn't based on the constitution. Since there's no greater legal act than the constitution, when the supreme court makes a decision it means that the decision fits the constitution and for many Americans the constitution is almost a holy document that guides their lives. A negative externality can be for example the rise of extremism. During the reconstruction period Ku Klux Klan rose as a negative externality of the era. During the civil acts era they grew stronger again because racist people were enraged by things like desegregation.
The Minnesota State Seal is just another name for our flag. (I live in Minnesota) <span />
Eastern merchants banded together to reject the barter economy in Europe
