Specific Heat Capacity (SHC) Sections 21.6 & 21.7

Transcription

1 Specific Heat Capacity (SHC) Sections 21.6 & 21.7

2 apple pie Filling gets than crust

3 Filling gets than crust

4 Toppings get than crust

5 Toppings get than crust

6 beach Sand feels than water

7 Sand feels than water

8 energy added T

9 VOCAB specific heat capacity: amount of heat needed to raise temperature of 1 gram of a material by 1 C Specific heat of water: J/(g o C) Specific heat of gold: J/(g o C)

10 Why do different materials have different specific heat capacities? One reason is: Beyond the scope of this course1

11 One way of thinking about ite Specific heat capacity of an object to change its temperature LowSHC = low resistance = T HighSHC = high resistance = T Which objects have a higher specific heat capacity? pie crust / filling pizza crust / pizza toppings water / sand

12 Check your understanding You add 100 calories of heat to 100 grams of water & to a100 grams of iron. The water s temperature goes up only 1 degree. The iron s temperature goes up 20 degrees! Which material has a high SHC? Why? Which objects has a low SHC? Why?

13 Substance cal/g/ o C or cal/g/k Water Wood (typical) Soil (typical) Air Aluminum Marble Glass (typical) Iron/Steel Copper Silver Mercury Gold Lead SHC of a substance can be used to help decide which substance should be used for a specific purpose Would you use aluminum or iron to make pots and pans that heat up quicker? Answer: Explanation: Which heats up more slowly: aluminum or mercury? Answer: Explanation:

14 Specific heat capacity of water Water has the specific heat capacity of all materials. 1 cal/g Cor J/g C Used in systems in automobiles and other engines. If a liquid with a lower SHC were used instead of water, the engine s temp would rise faster and engine would overheat quickly.

15 weather Because of its high SHC, water tends to take in heat very slowly, but it also loses heat slowly. Water is than the air during the winter, and than the air during the summer.

16 Specific Heat Song:

17 Chapter 21 Section (p ) Reading Guide 21.6 Specific Heat Capacity Different substances have different for storing or heat. o It takes min for water to reach 100 C o It takes min for iron to reach 100 C??? Which one has a higher specific heat capacity-iron or water? Why?????? Which one has a lower specific heat capacity-iron or water? Why??? Specific Heat Capacity is the amount of required to raise the of a unit mass of a substance by 1 C. SHC is like the thermal or resistance of a substance o change its temperature. 1

18 Chapter 21 Reading Guide Section (p ) Examples of Specific Heat Capacity in Everyday Life Which substance feels hotter when exposed to the same heat source? Which substance has the higher specific heat capacity? Beach sand Ocean water Beach sand Ocean water Pizza cheese Pizza crust Pizza cheese Pizza crust Sidewalk Grass Sidewalk Grass Metal pot handle Plastic pot handle Metal pot handle Plastic pot handle 21.7 The High Specific Heat Capacity of Water Water has a much capacity for storing (heat) than most common materials. A small amount of water absorbs a amount of heat for a temperature rise. Because of this, water is a very useful agent. If a liquid of lower were used in cooling systems, its temperature will be when absorbing the same amount of heat. 2

19 Chapter 21 Section (p ) Reading Guide 21.6 Specific Heat Capacity Different substances have different for storing or heat. o It takes min for water to reach 100 C o It takes min for iron to reach 100 C??? Which one has a higher specific heat capacity-iron or water? Why?????? Which one has a lower specific heat capacity-iron or water? Why??? Specific Heat Capacity is the amount of required to raise the of a unit mass of a substance by 1 C. SHC is like the thermal or resistance of a substance o change its temperature. 1

20 Chapter 21 Reading Guide Section (p ) Examples of Specific Heat Capacity in Everyday Life Which substance feels hotter when exposed to the same heat source? Which substance has the higher specific heat capacity? Beach sand Ocean water Beach sand Ocean water Pizza cheese Pizza crust Pizza cheese Pizza crust Sidewalk Grass Sidewalk Grass Metal pot handle Plastic pot handle Metal pot handle Plastic pot handle 21.7 The High Specific Heat Capacity of Water Water has a much capacity for storing (heat) than most common materials. A small amount of water absorbs a amount of heat for a temperature rise. Because of this, water is a very useful agent. If a liquid of lower were used in cooling systems, its temperature will be when absorbing the same amount of heat. 2