History

#88 Why is Venice where it is?

I learned this today. Venice was built on 118 small islands in a marshy lagoon because the people from local Roman cities were fleeing waves of Germanic and Hun invasions. The city of Venice was founded at noon on Friday 25th March, 421 AD with the dedication of the first church. Construction started possibly five

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#85 When did people start using money?

The first ever money was the Mesopotamian shekel, used about 5,000 years ago. Before we had money, people used the bartering system. Bartering probably started when hunter-gatherers began to form larger groups. When hunter-gatherers were in small groups, they could service all of their own needs. They only needed food, clothing, and shelter. Once the

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#84 Why is London where it is?

I learned this today. London was built where it is because it is the closest point to the sea that could be bridged. There may have been a small settlement where London is from prehistoric times, but there is no real evidence for that. There is, however, evidence of a bridge crossing the river Thames

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#64 What is the difference between alternating current (AC) and direct current (DC)?

I learned this today. The difference between AC and DC current is that in DC the charge only flows in one direction but in AC it changes direction periodically. Direct current (DC) was first produced in 1800 by the Italian physicist Alessandro Volta. That is why the volt is named after him. He produced electricity

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