Unit 10: reflection and cool lasers

   Today was fun, we got to play around with lasers. We learned about the electromagnetic spectrum, that is a way to organize different types of light waves. The one with the lowest frequency and longest waves is radio waves, next is microwaves, then infa-red, visible spectrum (colors), UV rays, x-rays then finally gamma rays. We looked more at the visible spectrum which consists of colors, ROYGBIV. The primary light colors are red, blue and green. This got really confusing because it is all different than painting colors. Mr. Blake shot some lasers around the room to show us how we cannot actually see the path of the laser just the start and end points. However when he sprayed "Cancer in a Can" it put stuff in the air and we were able to see the path. He then projected red on the white board and he would add green. This made the board yellow, when red was mixed with blue it made magenta. Finally when green was mixed with blue it made cyan. When all of them were mixed it made this off white color, it should have made white but not all the frequencies were the same. Mr. Blake then stood infront of the white board blocking one color at a time. This made a shadow or an absence of light. 

Mr. Blake with his blue and green shadows.

   Next we learned about reflection, this is where I got really confused. There is a law that says the the angle of incidence is equal to the angle of reflection but only when relative to normal. There are also two types of reflections, specular and diffuse. A specular reflection is when the image is the same as the object, this takes place when the foundation is smooth such as a mirror. Diffuse reflection is when the light spreads out, like on the white board.