Unit 10

Today in class we started our last unit on electromagnetic waves and light. We learned the fundamental concepts about light, and we put into perspective the speed of light. I was amazed to learn that sound can travel 3.5 football fields per second, while light can travel 3 million football fields per second. I knew light travelled a lot faster than sound, but I never knew how much faster. Another aspect of light we focused on was the transparency of it. There are three levels of transparency. There is opaque (where no visible light can pass through it), translucent (where some visible light can pass through it) and transparent (where visible light can fully pass through). Once I started thinking about these three terms, I wondered if there were things that had multiple transparencies in one object. It turned out it was very common. One example is a clock; the surface of a clock is totally transparent so you can see the numbers behind it. Yet the second layer of a clock is opaque – if the second layer weren’t opaque, it would be very hard to read the time, as all the mechanisms of the clock would be visible. This made me think about how the functionality of many objects depends on what transparency the material has.