Goering,+Bret

Trick Candles I never realized how dangerous trick candles are. I use magnesium as a fire starter sometimes so i have seen just how flamable it is. It is fascinating though how it actually re-lights, I never thought it could consistently re-light by that method. That method sounds like it would be inconsistent and not work every time but I'm impressed that they can make it work.

Bret, I'd like to try and make some but I need powdered Mg. 5 stars! MW

Kilogram I found it interesting how big of a deal the kilogram losing 50 µg was. This was especially surprising because it only affects such a small amount of scientists. I think it is a much better idea to use numbers rather than a physical object because of exactly this reason. An SI has to be so precise that numbers are the only real way to accomplish that. I also don't think the switch to numbers over a physical standard will be very hard, it is a very easy and needed switch.

Bret, Not sure I see 3 things picked out of this article. 4 stars. MW

Motion Sensor I thought that the different ways that motion sensors work are really interesting. The way that we can see through glass but infrared light can't is very surprising. I also thought it was pretty cool that infrared light can see through some opaque material too. One of the methods used heat to detect movement and I thought it was especially cool that it had a filter to screen out all types of radiation that weren't close to the radiation that the body gives off. Overall I found out that motion sensors do a lot of cool things like protect people to let a shop keeper know a customer has arrived.

Bret, I guess you can tune motion detectors to detect anything! I can think of a few uses for that. Pretty cool idea. 5 stars. MW