Hollander,+Bethann

Motion Detectors 10/4/11 I have always wondered how motion detectors at home and in automatic doors worked and I was surprised to find that automatic doors worked by sending radio waves to tell if there is someone in front of the door. It didn't occur to me that signals bouncing off of objects would be used to detect objects besides in the ocean with sound waves bouncing back, called sonar. I also wondered why the motion detector at my house was covered in a plastic like from a milk carton and as a kid I assumed it was to hide the fact that it was a motion detector. I now realize that it is because it transits this certain type of light, IR light, whereas glass doesn't, and I found this interesting that glass blocks this light and plastic doesn't but plastic can be seen through by the human eye and plastic can't. In class we are learning how different light or radiation waves work and I now know they can even help motion detectors work.

Bethann, Looks good! Nice writing style. 5 stars. MW

Video 9/19/11: Distillation I learned that the lower boiling point collects at the top which makes sense because that means that they change states to a gas more quickly than the ones under them. I found it interesting that crude oil is the most common element that people have fought wars over including the war with Iraq. At first I thought it was going to be water but I was wrong in my prediction. Crude oil is so important because many things come from it including gasoline, naphtha, kerosene, and more, which are all a huge deal in our societies today. It is relevant to our class because we used this same method of distillation with a mixture of dissolved blue crystals of sodium carbonate and water.

Bethann,

Wow! Great post! BTW it was copper(II) sulfate that we separated from the water. :) 5 stars. MW

I already knew that tattoos were becoming more and more popular and that they were starting to create tattoos made of temporary ink. I also knew that they can contain different chemicals that can be harmful to create different colors. I learned that white can be created with titanium dioxide, zinc oxide, or lead carbonate. I also learned that some of the new colors chemistry has introduced to the tattooing artists has not been safety tested for humans. I didn't know that the ink is injected into the dermis which this article showed me but I had already known that once there it stays there permanently.

Bethann,

Looks good. I like the idea of an "erasable" tattoo. 5 stars. Pr