1. LecturePLUS Timberlake 99 Warm Up A. When you touch ice, heat is transferred from 1) your hand to the ice 2) the ice to your hand B. When you drink a hot cup of coffee, heat is transferred from 1) your mouth to the coffee 2) the coffee to your mouth

2. LecturePLUS Timberlake 992 Warm Up Solution A. When you touch ice, heat is transferred from 1) your hand to the ice B. When you drink a hot cup of coffee, heat is transferred from 2) the coffee to your mouth

3. 3 Calculating Heat Energy

4. 4 Question?? Which would take longer to heat to 80 degrees, a bathtub full of water or a beaker of water? Why??

5. LecturePLUS Timberlake 995 Question? Why is the beach sand hot, but the water is cool on the same hot day?

6. LecturePLUS Timberlake 996 Specific Heat Different substances have different capacities for storing energy It may take 20 minutes to heat water to 75°C. However, the same mass of aluminum might require 5 minutes and the same amount of copper may take only 2 minutes to reach the same temperature.

7. LecturePLUS Timberlake 997 Specific Heat Specific heat is the a mount of heat needed to raise the temperature of 1 g of a substance by 1°C J/g°C water 4.18 aluminum 0.90 copper 0.39 silver 0.24 gold 0.13

8. LecturePLUS Timberlake 998 Specific Heat A. A substance with a large specific heat heats up slowly Ex. Water 4.18 J/g C B. A substance with a small specific heat heats up quickly. Ex. Gold 0.13 J/g C

9. LecturePLUS Timberlake 999 Question?? Sand in the desert is hot in the day, and cool at night. Sand must have a low specific heat

10. 10 Calculating Heat, q heat = mass x specific heat x change temp. q = m x c x  T (final-initial)

11. LecturePLUS Timberlake 9911 Heat Calculations Practice!! A hot-water bottle contains 750 g of water at 70°C. If the water cools to body temperature (37°C), how many joules heat could be transferred to sore muscles? C= 4.18 Heat = m x c x  T (final-initial) q = 750 g x 4.18 x 33°C q = 103,455 Joules