Big History Quiz

Light travels through different mediums before it reaches our eyes. Since its propagation speed depends on the density of the medium, it breaks at the boundary of different densities. The image of objects does not come into our eyes from where they are, but rather from where we think we can see their shape after refraction.

The lychee was first cultivated in southern China, and was a popular delicacy in the Chinese Imperial Court. It made this impression on a European traveler in 1585: “They haue a kinde of plummes, that they doo call lechias, that are of an exceeding gallant tast, and neuer hurteth any body, although they shoulde eate a great number of them.”

Although mathematics is the cold and factual language of science and reason, sometimes it can seem quite magical. For instance, if you multiply 111,111,111 with 111,111,111, the amazing product is 12,345,678,987,654,321.