Bruck,+Danielle

1~24~11

The coin article was an interesting read for me because both me and my dad collect coins and money. I already knew that coins were not composed of pure metals so that wasn't a new fact to me. I did find it interesting that all coins were originally composed of the same three metals; gold, silver, and copper. I also learned that those pure metals would be too soft for the wear and tear that circulated coins experience. In a penny for example, it used to be almost pure copper but changed to mostly zinc because of the cheaper cost of production of the coins. It was interesting to hear that all of our "silver" coins have absolutely no silver in them. I found it interesting about the mustard test for the silver and I think it would be interesting to see if it works. It was also funny to hear of other coin experiments like cleaning pennies, and separating the two parts of a $2 Canadian coin.

Danielle, Good post! Looks like you learned quite a bit from this article. I hope you shared it wit your Dad! 5 stars. MW

2~8~11 Redefining the Kilogram

In this article I found it interesting that out of all of the seven SI units, the kilogram is the only one that is a physical artifact rather than an unvarying physical property of nature. I also found it interesting that since the original prototype defined as the kilogram has lost some mass, the new kilogram will be defined based off of a new calibration. I thought that it was also interesting that the kilogram was not the only thing being redefined. The Avogadro's number is also being questioned and debated upon.

Danielle, OK.Looks like you picked out some main points. 5 stars. MW

2~25~11 Motion Detectors

In this article, I found it interesting that there is more than one type of motion detector. There are ones that detect by light, sound, or heat. The article talked about light and the waves of light and it mentioned that photons, or particles of light, are measured by amount rather than energy held by each one. I noticed that we are going to be learning about light waves and the electromagnetic spectrum. That is why the light detecting motion detectors relates to our class.

Danielle, Kind of bare bones. Did you find three distinct things to discuss? 4 stars. MW