General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Tutorial Times  8 am to 8:30 am  11:45- 12:09 (2 nd part of lunch)  4 pm  Let me know in advance if you will be coming…remember, you have one week for make up work 1

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. REVIEW-What is this picture illustrating ? 2

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Newton’s Law of Cooling 3

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Newton’s law of cooling  At crime scenes, allows you to test for the time of death.  Allows you to predict how long it will take for food to cool down 4

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Definition-the rate of cooling of an object is proportional to the temperature difference between the object and its surrounding 5

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. … or how fast something cools is whether the temperature difference is big or little For example- Would a hot cup of tea get to room temperature faster than a warm cup of tea?  No. Although the rate of cooling is greater for the hotter cup, it has farther to cool to reach thermal equilibrium. Cooling rate and time are not the same thing. 6

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Review Will a can of soda cool faster in the refrigerator or freezer? Why? It cools faster in the freezer b/c the rate of cooling is proportional to the difference in temperature 7

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Review On a very cold day, does it cost more to keep your house 70º F or 65º F? Why? A warm house loses heat to the outside cold faster when there is a large temperature difference between the inside and outside temperature. If you keep the temp difference small, the rate of cooling is small 8

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Next Topic…The Greenhouse Effect 9

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. The Greenhouse effect Named for the temperature raising effect in a greenhouse 10

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. The same effect happens in a hot car…the inside of car becomes hotter if the windows are rolled up 11

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. 2 Things To Remember High energy waves have short wavelengths…low energy waves have long wavelengths When the sun comes into your car it has short wavelengths (the sun is so much hotter than your car). It passes easily into the windows of the car. 12

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. 2 Things To Remember 1) Some rays are reflected. 2) Most of the energy is absorbed, so the interior of the car warms up. 13

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. 2 Things To Remember 3)The car now radiates its own waves (b/c the car is not as hot as the sun), its waves are short wavelengths 4)The car becomes even hotter 14

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. The same effect occur in the Earth’s atmosphere 15

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. The normal global warming process is a balance…if we didn’t have it the temp of the earth would be -18ºC.  Over the last 500,000 years, the Earth’s temp has fluctuated between 16º C-27ºC. Presently we are at the high end.. 27ºC. 16

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. FYI 17

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. FYI 18

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. A theory 1) higher temp = warmer oceans 2) warmer oceans= increased evaporation 3) Evaporation = increased snowfall 4) Increased snow = increased reflection of sun 19

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. A theory Sooo…increased temperatures can lead to a significant drop in global temperature 20

General, Organic, and Biological ChemistryCopyright © 2010 Pearson Education, Inc. Explain this cartoon 21