The non-textbook reading I shared with classes for a different perspective may be seen here
Today, labs were turned in, we looked at the forecast and it appears our barometer will measure some high pressure while we're gone rather than here this weekend. :(
I answered questions on the lab that you were supposed to guess on: can water/ice get colder than 0 degrees C? Yes. As a matter of fact the ice you worked with in class was much colder. Just at the surface, we see water and melting ice at 0C.
Can water vapor get hotter than 100C? Yes. Your teachers next year will surely do a demonstration with superheated water vapor/steam, or you can look up some cool stuff on youtube.
Where do the bubbles form in boiling water, and what are they? They should appear at the bottom of the container as long as it's being heated from the bottom (smart if it's following convection rules)... and the bubbles are Water Vapor - that explains where they come from - water expands and jumps to the gas stage, which is much less dense, and moves to the top of the water as a bubble.
We looked at the graphs of heating water and identified that most people's graphs showed little change in temperature of the ice/water until the ice melted, and little change in temperature while boiling. That's because when phase changes are occurring, any energy transfer is going into changing the phase of the water, not into changing the water's temperature. It takes a great amount of energy to change phase.
Two definitions: Heat of fusion: the amt. of E required to freeze/melt water
Heat of vaporization: Amt of E required to vaporize/condense water. (note - this may happen at temperatures other than boiling point! - ex. you when you get out of the shower, etc.)
Latent heat: E stored/released (hidden) in liquid/solid/gas states of water - released and absorbed in phase changes. Latent heat is not detectable by a thermometer alone; the total energy content of air is well connected to its humidity.
On Monday, we'll have some problems to help guide your review. I have listened to suggestions and we will have harder review questions that are involving transfer to unique situations and will challenge you as much as or more than the exam will. Tuesday we'll take a departure (from weather) and deal with one facet of global climate: energy efficiency - why/why not and how you can make a difference for your pocketbook and our resources. (goes along with the optional assignment I posted yesterday)
Wednesday we'll have a QUEST on meteorology: smaller than a test, bigger than a quiz.
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