Presentation is loading. Please wait.

Presentation is loading. Please wait.

Temperature We often associate temperature with how __________ something feels We often associate temperature with how __________ something feels Hot.

Similar presentations


Presentation on theme: "Temperature We often associate temperature with how __________ something feels We often associate temperature with how __________ something feels Hot."— Presentation transcript:

1

2 Temperature We often associate temperature with how __________ something feels We often associate temperature with how __________ something feels Hot and Cold are terms that can be ___________________ Hot and Cold are terms that can be ___________________ The same object can feel warm or cool depending on the properties of the object and the condition of your body The same object can feel warm or cool depending on the properties of the object and the condition of your body

3 Hot Cold Luke warm

4 Moving Energy Changes Temp. Consider an oven- turn the dial on and heat is delivered as energy flows. When the dial is off, energy stops flowing and temperature cools Consider an oven- turn the dial on and heat is delivered as energy flows. When the dial is off, energy stops flowing and temperature cools

5 Temperature Temperature is proportional to the _____________ of atoms and molecules. Temperature is proportional to the _____________ of atoms and molecules. To understand temperature, think of atoms & molecules and _____________. With more heat, atoms move more, have more KE. When heat is removed, the energy of theses moving atoms/ molecules is called _________________. To understand temperature, think of atoms & molecules and _____________. With more heat, atoms move more, have more KE. When heat is removed, the energy of theses moving atoms/ molecules is called _________________.

6 Internal Energy The energy of substance due to the ______________ of its component particles and equal to the total energy of those particles The energy of substance due to the ______________ of its component particles and equal to the total energy of those particles

7 Thermal Equilibrium The state in which two bodies in physical contact with each other have ____________ temperatures The state in which two bodies in physical contact with each other have ____________ temperatures COLDWATER Warm Beverage In time both liquids will have equal temperatures

8 You can not find __________________ until thermal equilibrium is reached You can not find __________________ until thermal equilibrium is reached The temperature of the liquid in the thermometer must _______________ the temperature of the object being measured. This must happen in order to know the temperature The temperature of the liquid in the thermometer must _______________ the temperature of the object being measured. This must happen in order to know the temperature “You don’t read a thermometer until the mercury/ alcohol has stopped rising/ falling” “You don’t read a thermometer until the mercury/ alcohol has stopped rising/ falling”

9 Thermal Expansion Things get _________ they EXPAND Things get _________ they EXPAND Things get _________ they CONTRACT Things get _________ they CONTRACT – Concrete bridges – Rail Road Rails – Power Lines – Hot glass – cold water – cracks This is True for all solids, liquids and gasses (some more than others) This is True for all solids, liquids and gasses (some more than others)

10 Anomaly of Water A strange thing happens to water between _____________: as it gets colder, it EXPANDS- GOOD NEWS FOR FISH!! A strange thing happens to water between _____________: as it gets colder, it EXPANDS- GOOD NEWS FOR FISH!!

11 ICE 0°C 1°1°1°1° 2°2°2°2° 3°3°3°3° 4°4°4°4°

12 Thermometers A glass tube containing a thin column of mercury, colored alcohol, or colored mineral spirits A glass tube containing a thin column of mercury, colored alcohol, or colored mineral spirits When heated, Liquid _________________ When heated, Liquid _________________

13 To calibrate thermometers and to set a standard for temperature we have chosen water to be our bench mark.- Not just any water – ______ _________________________ To calibrate thermometers and to set a standard for temperature we have chosen water to be our bench mark.- Not just any water – ______ _________________________ Calibrating Thermometers

14 What About Fahrenheit We must convert with the following formulas: We must convert with the following formulas: – To find °F °F = 9/5(°C) + 32 – To Find °C °C = 5/9(°F - 32)

15 With °F and °C, often times you get negative numbers; This is because many things are colder than our standard “________” With °F and °C, often times you get negative numbers; This is because many things are colder than our standard “________” To eliminate neg. values for temperature, the ___________ was used To eliminate neg. values for temperature, the ___________ was used – 0 Kelvin is as cold as anything can get – From 0 K, you can only go up Kelvin Scale

16 The best thermal lab on record has reached 0.0000001 K The best thermal lab on record has reached 0.0000001 K At 0K, the theory states that ___________ would cease to vibrate At 0K, the theory states that ___________ would cease to vibrate

17 Kelvin Conversions To find K Kelvin temp = °C + 273.15 To find K Kelvin temp = °C + 273.15 To find °C °C = Kelvin Temp - 273.15 To find °C °C = Kelvin Temp - 273.15 Practice Problems 10A 1-5 pg. 3 HOMEWORK 2, 4, 5, 7, 9, 10 pg. 12

18 Section 10-2 Defining Heat Defining HeatReadandUnderstand

19 Defining Heat Heat: – Flow of _________ – Moves in one direction, from ____ to ________ – Symbol _____ – Has units for energy (Joule) (calorie, kilocalorie, dietary calorie, Btu, therm)

20 Specific Heat Capacity This is the amount of energy required to change the temperature of 1Kg of a substance by °C This is the amount of energy required to change the temperature of 1Kg of a substance by °C Cp = Q/ m Δ T Q = m CP Δ T Q = Heat (Joules) m = mass (Kg) Cp = Specific Heat (J/Kg°C) Δ T = change in temp (°C)

21 Table 10.4 (pg. 7) Substances take differing amounts of energy to heat up Substances take differing amounts of energy to heat up – Water heats up _________ – Lead heats up ________

22 Calorimetry To determine specific heat capacity we do calorimetry To determine specific heat capacity we do calorimetry For calorimetry always remember: For calorimetry always remember: Energy absorbed = Energy released Q water = Q x C p w M w Δ T w = Cp x M x Δ T x

23 Practice Problems: 10c Pg.8 7, 6, 5, 4 Homework: Pg.12 -13 13, 14, 16, 21, 22, 28

24 Latent Heat _______________ Latent heat is the heat needed to change the physical ______ of a substance (at constant pressure) Latent heat is the heat needed to change the physical ______ of a substance (at constant pressure) SOLIDLIQUIDGAS

25 Latent Heat Ice chest: mostly ice - little water (temp 0°C) Ice chest: mostly ice - little water (temp 0°C) Ice chest: mostly water - little ice (temp 0°C) Ice chest: mostly water - little ice (temp 0°C) Heat was added to melt the ice but temp didn’t change Boiling water: 100°C- doesn’t get hotter until all water is gone, Even though heat is continually added the water stays at 100°C Boiling water: 100°C- doesn’t get hotter until all water is gone, Even though heat is continually added the water stays at 100°C These examples show latent heat All substances have this hidden heat (gold, lead, aluminum, water, copper, ect.)

26 2 Types of Latent Heat Both have the same units of heat (J) and symbol Q Both have the same units of heat (J) and symbol Q ________________: the energy per unit mass transferred in order to change a substance from liquid to solid or solid to liquid ________________: the energy per unit mass transferred in order to change a substance from liquid to solid or solid to liquid ________________: the energy per unit mass transferred in order to change a substance from liquid to vapor or vapor to liquid ________________: the energy per unit mass transferred in order to change a substance from liquid to vapor or vapor to liquid

27 Formula for Latent Heat Q = mL f/v Q = Heat m = mass L v = heat of vaporization L f = heat of fusion Look at table 10-6

28 OVERHEAD

29 Heat Flow ____________________: this is how heat flows through a substance. Some materials conduct heat well. others are very poor (insulators) ____________________: this is how heat flows through a substance. Some materials conduct heat well. others are very poor (insulators) Generally, metals are good conductors of heat. Asbestos, cork, ceramic, cardboard,& fiberglass are good insulators Generally, metals are good conductors of heat. Asbestos, cork, ceramic, cardboard,& fiberglass are good insulators

30 Heat Moves in 3 Ways ___________: heat moving through 2 objects that touch each other ___________: heat moving through 2 objects that touch each other ___________: heating by movement of fluids(liquids and gases). Involves displacement of cold matter by hot ___________: heating by movement of fluids(liquids and gases). Involves displacement of cold matter by hot

31 Heat Movement Cont… ________________: electromagnetic rays carry heat from everything above 0 Kelvin in the form of waves. Nom medium is needed for this- occurs in the vacuum of space. Also, near a campfire ________________: electromagnetic rays carry heat from everything above 0 Kelvin in the form of waves. Nom medium is needed for this- occurs in the vacuum of space. Also, near a campfire

32 Thermos Keeps hot things hot, cold things cold because it minimizes heat flow Keeps hot things hot, cold things cold because it minimizes heat flowOVERHEAD

33 Clothes & climate – Eskimo- Parka – Arabian - Desert Dress

34 Section Review HOMEWORK: 29, 32, 33 - 39

35


Download ppt "Temperature We often associate temperature with how __________ something feels We often associate temperature with how __________ something feels Hot."

Similar presentations


Ads by Google