What is a rabbi? Judaism – Religion
The rabbi Maimonides, in a later medieval painting What does "rabbi" mean? Rabbi means "great one" in Hebrew, or "respected one". It's a Hebrew word related to the Arabic word rabb, [...]
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08, 2017
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08, 2017
What is baptism? – History of Christianity
Torchlight parade (this one is actually in India) Baptism before Christianity Even before the time of Jesus, many mystery religions of the ancient Mediterranean had some sort of ceremony that people had to do in [...]
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08, 2017
What is work? Physics definitions
Ancient Egyptian cattle plowing (Louvre Museum, Paris) You might think you know what work is, like homework, or having to pick up your room, right? But to scientists, work has [...]
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08, 2017
What is a light-year? Physics definitions
Light takes years to reach us from these stars far away in space. What is a light-year? A light-year is the distance that light can travel in one year - [...]
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08, 2017
What is feudalism? Definition of medieval feudalism
Medieval feudalism: Harold swears an oath to William (Bayeux Tapestry, about 1077 AD) What is feudalism? Feudalism is a way to govern a large state when the king is poor and not very powerful, [...]
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07, 2017
What is area? Simple geometry
Calculating the area of your room. The area of a room is the size of the floor. Suppose you wanted to find out whether your room was really bigger than [...]
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07, 2017
Solids – Platonic solids – Geometry
Pyramid Just as a plane is made of an infinite number of lines, a solid is made of an infinite number of planes. These planes are right next to each other, like [...]
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07, 2017
What is a rhombus? Simple geometry
This is a rhombus, divided so you can figure out the area. A rhombus is a kind of quadrilateral that has two sides that are parallel to each other, and another two sides that [...]
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07, 2017
Rectangle – area and perimeter
This is a rectangle. A rectangle is a flat shape, in one plane. It's defined by four points at the four corners. A rectangle has two sides of equal length opposite each other, [...]
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07, 2017
What is a pyramid? Square pyramids
A pyramid with a square base. A pyramid is a three-dimensional solid form made out of triangles. Some pyramids also use a square. There are two common kinds of pyramids: triangular pyramids that you [...]
