Lessons 23&24 (not doing experiments for in class)

Lesson 23: This lesson is about another Ancient philosopher named Euclid (yoo-klid) who lived around the year 300BC. One of the ideas he is known for is something called the Law of Reflection. The basic idea of this Law is that light bounces off of objects, kind of like a ball does. If you drop a ball straight down, if the surface is flat, the ball will bounce straight back up. If you toss a ball at an angle, it will bounce off the ground at a similar angle away from you. Light does this too. An angle is another word for a corner, or the amount of space between two lines that meet in a corner. In your house, a normal corner has 90degrees, like a square. Half of that amount of space is 45degrees. If you throw a ball at 45 degrees, it will bounce up at 45 degrees away from you. Light does this exact same thing. If light hits a mirror at 35 degrees, it will bounce off at 35 degrees away from you. If light hits a mirror at 15 degrees, it will bounce off at 15 degrees away from you in the opposite direction. 

Lesson 24: Archimedes : Archimeds lived at the same time as Aristarchus. He helped us understand how liquid affects objects.  He saw how an object seems to be easier to move when in the water and that they fall slower than they would out of water. He learned through experience that water actually pushes upwards on objects and makes them not be affected by gravity. He figured out that water pushes upwards on an object with a force equal to the weight of the water the object “displaced” or moved when it was placed in the water. This is called Archimeds’s principle.