14 December 2010

Today we read about and discussed how energy is involved with changes in states of matter. For example, a substance changing from a liquid to a solid (aka freezing) or from a gas to a liquid (aka condensing). We also read about how freezing and condensation give up energy and are called exothermic. On the other hand, vaporization (boiling and evaporation), melting, and sublimation are endothermic, or require the substance to gain energy.

Here is another video to help students review the material we covered today: http://www1.teachertube.com/viewVideo.php?video_id=111175&title=States_of_Matter___Part_2&vpkey=&album_id=

In some classes, we discussed how this relates to the lab we did at the beginning of the unit. We looked at how our graphs compared to the graphs in the book and noticed that once the water started to boil at 100 degrees Celsius, the temperature stayed the same as the water boiled. Similarly, as we froze some water, the temperature stayed at 0 degrees Celsius until it had completely frozen. The classes that did not get a chance to discuss this will be discussing it tomorrow before we review for the test.

As we have come to the end of the unit on states of matter, we will be having a test on Thursday the 16th.

• Students should review p. 72-81 of their notebooks to prepare for this test.
• Left side activities should be completed for pages 74, 78, 80 in their notebooks.
  
• If they are looking at the online book (see my web page for the link under "Useful Links") it is Chapter 6.
• A Chapter Review will be given to the students on Wednesday (completed as homework) and we will go over it before the test.