Note on Posted Slides These are the slides that I intended to show in class on Wed. Feb. 13, 2013. They contain important ideas and questions from your.

Slides:



Advertisements
Similar presentations
Chapter 9 Thermal Energy
Advertisements

CONCEPTUAL PHYSICS HEWITT, 1999 BLOOM HIGH SCHOOL Chapter 21 Temperature, Heat and Expansion.
Chapter 17 Heat.
Thermal Energy & Thermodynamics
Thermal Physics.
TEMPERATURE, HEAT AND EXPANSION
TEMPERATURE, HEAT AND EXPANSION
Temperature, Heat, and Expansion. Temperature Most materials expand when heated Liquid thermometers based on mercury or alcohol expansion are common Temperature.
Conceptual Physics 11th Edition
Temperature Physics 202 Professor Lee Carkner Lecture 12.
Temperature, Heat & Expansion. Temperature - The quantity that tells how hot or cold something is compared with a standard. Temperature - The quantity.
* Measured in K, ºC, ºF * Lower limit … 0 K * Upper limit … none * K and ºC have the same scale, just offset * Practice converting to all three scales:
PHY205H1F Summer Physics of Everyday Life Class 5: Temperature, Heat Temperature Heat Specific Heat Capacity Thermal Expansion Thermal Expansion of Water.
Temperature, Heat, and Expansion. Temperature Most materials expand when heated Liquid thermometers based on mercury or alcohol expansion are common Temperature.
L 17 - Thermodynamics [2] Today’s topics
L 17 - Thermodynamics [2] Today’s topics –Practical thermal effects –Devices for temperature measurement –Mechanisms of heat transfer Science dealing.
Heat © 2013 Pearson Education, Inc..
Temperature, Heat, and Expansion
Heat, Temperature, and Expansion
Temperature, Heat, and Expansion
1 1 Temperature and Thermal Energy Temperature and energy Glencoe: Chapter 9 – Section 1: pages
HEAT.
Temperature, Heat and Expansion. All matter – solid, liquid and gas – is composed of continually jiggling atoms or molecules. These atoms and molecules.
THERMAL ENERGY AND THERMODYNAMICS
Thermodynamics Chapter 12.
Conceptual Physics 11th Edition
 Matter takes up space and has mass  Matter is made of atoms, usually chemically bonded into molecules  Exists in different states.
Heat and States of Matter
Lecture 7 Temperature and Heat. Buoyancy. Chapter 4.1  4.6 Outline Temperature and Heat Density and Pressure Buoyancy.
Heat and Temperature The heat, as Glen Frey says, is on.
© 2012 Pearson Education, Inc. Conceptual Physical Science 5 th Edition Chapter 6: THERMAL ENERGY AND THERMODYNAMICS © 2012 Pearson Education, Inc.
HEAT Miller. Introduction: Temperature = a measure of the AVERAGE kinetic energy in a substance. Heat energy is measure in Joules.
Count Rumford supervised the drilling of brass cannons in a factory in Bavaria. From his observations, Rumford concluded that heat is not a form of matter.
“Everything around us is made up of energy. To attract positive things in your life, start by giving off positive energy.” - Unknown 16.1 – Thermal Energy.
In the 1700s, most scientists thought heat was a fluid called caloric.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison Wesley Chapter 6: THERMAL ENERGY AND THERMODYNAMICS.
Iceland Volcanoes! Heat and Thermal Energy. The Thermal Energy of a substance is the total energy of all of its molecules and atoms. It consists of both.
Chapter 9 Thermal Energy. Thermal Energy “the total energy of all its atoms and molecules as they wiggle & jiggle, twist & turn, vibrate or race back.
UNIT 5: HEAT. What is heat? What is temperature? How are these related to each other?
4-Jun-16 Physics 1 (Garcia) SJSU Chapter 21 Temperature, Heat & Thermal Expansion Part III: Heat.
Heat Temperature. u Related to average kinetic energy of molecules u Measured on a scale based on some standard u Read with thermometer containing material.
Heat and Temperature Chapter 14.
Temperature & Heat. Kinetic Molecular Theory Matter is composed of tiny particles – Atoms – Molecules The particles of matter are in constant random motion.
Thermal Force Unit 1.4
Chapter 5 Thermal Energy
Temperature Heat And Temperature ExpansionWaterPotpourri.
Physics 101: Lecture 22, Pg 1 Physics 101: Lecture 22 Temperature and Ideal Gas Final.
Whenever something becomes warmer, the kinetic energy of its atoms or molecules has increased. When the atoms or molecules in matter move faster, the matter.
Heat and Temperature Heat and Temperature. Heat and Temperature Is it cold in here? Is it cold in here? How about outside? How about outside? What would.
Investigation One.  The term used to describe the total of all the energy within a substance.  Heat is also known as thermal energy.  Includes both.
Thermal Energy & Heat 1.Temperature – The measure of the average kinetic energy of the particles that make up a substance. 2.Temperature Scales – Fahrenheit,
Thermal Energy and Heat. Temperature Temperature is a measure of the average kinetic energy of the individual particles in matter. The higher the temperature,
Applied Science III Mr. Finau. What is Temperature?  Temperature is the measurement of how warm or cold a system is  A system means a particular area.
Lecture Outline Chapter 15: Temperature, Heat, and Expansion © 2015 Pearson Education, Inc.
 Has fixed volume  Has fixed shape  Molecules are held in specific locations  by electrical forces  vibrate about equilibrium positions  Can be.
Chapter 21: Temperature, Heat and Expansion. What is “normal” body temperature and what instrument is used to measure it? 98.6 degrees Fahrenheit A thermometer.
Chapter 1.  Chemistry is the study of matter and the transformations it can undergo  Matter is anything that occupies space  Chemistry is a central.
Chapter 9 Heat!. Temperature and Thermal Energy Although closely related, these things are NOT the same thing!!!!
Temperature, Heat, and Expansion When matter gets warmer you are giving it energy. This makes the atoms or molecules in the matter move faster -If you.
Temperature, heat, and expansion
Temperature and Heat Kinetic theory – particles are constantly moving and have kinetic energy. The higher the temperature, the faster they move, so the.
Count Rumford supervised the drilling of brass cannons in a factory in Bavaria. From his observations, Rumford concluded that heat is not a form of matter.
TEMPERATURE, HEAT AND EXPANSION
Conceptual Physics 11th Edition
Thermal Energy and Heat
16.1 – Thermal Energy & Matter
Conceptual Physics 11th Edition
Conceptual Physics Fundamentals
Temperature, Heat, and Expansion
Presentation transcript:

Note on Posted Slides These are the slides that I intended to show in class on Wed. Feb. 13, 2013. They contain important ideas and questions from your reading. Due to time constraints, I was probably not able to show all the slides during class. They are all posted here for completeness.

PHY205H1S Physics of Everyday Life Class 11: Temperature, Specific Heat and Thermal Expansion Specific Heat Capacity Thermal Expansion Thermal Expansion of Water and Ice [image from http://sirius.ucsc.edu/demoweb/cgi-bin/?fl_pr_ht-thermo-expansion/ ]

Chapter 15 Pre-class reading question What is the difference between a calorie and a Calorie? The unit Calorie is used in the U.K. and Canada, while the calorie is used in the U.S.A. One Calorie is 1000 calories. A Calorie is a unit of heat while a calorie is a unit of food energy. A calorie is 4.18 times smaller than a Calorie. They are both the same.

Chapter 15 Pre-class reading question An iron bar has a length of exactly 1.0000 m. If you double the temperature of this iron bar, what will happen to its length? Its length will double. It will get slightly longer. It will not change. It will get slightly shorter. Its length will drop by a factor of 2.

Inertia Demonstration A cart is covered by an enclosed transparent box. A ball is attached to the top of the box by a string. Predict: As the box is accelerating toward the right, which will be the best sketch of the situation? A B C

Buoyancy Demonstration A cart is covered by an enclosed transparent box. A helium-balloon is attached to the bottom of the box by a string. Predict: As the box is accelerating toward the right, which will be the best sketch of the situation? A B C

As the cart is accelerating to the right, the heavier air molecules are left behind, to the left, creating a tilted pressure gradient Lower air Density, Pressure Isobars (planes of equal pressure) Higher air Density, Pressure C

Another way of looking at it: Gravity acts like a result of acceleration. This was noted by Einstein and lead to his theory of General Relativity in 1915. Apparent direction of gravity inside accelerating box Apparent direction of gravity inside accelerating box

Temperature It’s one of the first things we think about in the morning: What’s the temperature like outside? We can measure temperature with a thermometer. Temperature has something to do with microscopic random motions of the atoms in a material A cold cup of coffee has a low amount of internal thermal energy If you put it in the microwave, the microwave radiation transfers energy to the coffee, increasing its internal thermal energy, which increases its temperature.

Temperature A number that corresponds to the warmth or coldness of an object Is a per-particle property No upper limit The lower limit is called “absolute zero”

Temperature Absolute temperature (in degrees Kelvin) is proportional to the average translational kinetic energy per particle in a substance. Gas—how fast the gas particles are bouncing around Liquid—how fast particles slide and jiggle past one another Solid—how fast particles move as they vibrate and jiggle in place [animated gif downloaded Jan.25 2013 from http://www.deanza.edu/faculty/mccauley/6a_site_images/Translational_motion-250.gif ]

Temperature CHECK YOUR NEIGHBOR There is twice as much molecular kinetic energy in 2 liters of boiling water as in 1 liter of boiling water. Which will be the same for both? A. Temperature Thermal energy Both A and B. Neither A nor B. A. Temperature.

Temperature CHECK YOUR NEIGHBOR To say that body A has a higher temperature than body B is to say that body A has more A. internal energy. mass. kinetic energy per particle. potential energy. C. kinetic energy per particle.

Thermometers Measure temperature by expansion or contraction of a liquid (mercury or colored alcohol) Reading occurs when the thermometer and the object reach thermal equilibrium (having the same average kinetic energy per particle) Infrared thermometers operate by sensing IR radiation [image downloaded Jan.25 2013 from http://drrajivdesaimd.com/date/2012/10/ ]

Temperature Scales 𝑇 𝐶 =( 𝑇 𝐹 −32)× 5 9 𝑇 𝐹 = 𝑇 𝐶 × 9 5 +32 To convert TF in Fahrenheit to TC in Celsius: 𝑇 𝐶 =( 𝑇 𝐹 −32)× 5 9 To convert TC in Celsius to TF in Fahrenheit: 𝑇 𝐹 = 𝑇 𝐶 × 9 5 +32 Though Canada officially switched to Celsius in 1970, Fahrenheit is still sometimes used, especially on kitchen appliances and in hospitals.

“Absolute” Temperature Note that temperature is due to the microscopic vibrations of the atoms in a material (internal thermal energy). The coldest possible temperature would be when this thermal energy dropped to zero: atoms STOPPED vibrating. For all materials, this happens at −273 °C The Kelvin temperature scale is the same as Celsius, but with a different zero point. Absolute zero has T = 0 K. To convert TC in Celsius to T in Kelvin: 𝑇= 𝑇 𝐶 +273 To convert T in Kelvin to TC in Celsius: 𝑇 𝐶 =𝑇−273

Temperature Conversion Example The commonly accepted average core body temperature for a human (taken internally) is 98.6 degrees Fahrenheit. What is this in Celsius? What is this in Kelvin?

Is it possible for an object to have a negative Kelvin temperature? CHECK YOUR NEIGHBOR Is it possible for an object to have a negative Kelvin temperature? Yes No A. Temperature.

Temperature scales summary Celsius 0C for freezing point of water 100C for boiling point of water Fahrenheit 32F for freezing point of water 212F for boiling point of water Kelvin 273 K for freezing point of water 373 K for boiling point of water 0 at absolute zero, when atoms have STOPPED vibrating! same size degrees as Celsius scale

Heat is a form of energy Flow of internal energy Heat is when internal energy is transferred from one thing to another due to a temperature difference Heat is internal energy in transit Flow of internal energy Heat flows from a high-temperature substance to a low-temperature substance until thermal equilibrium is reached Heat never flows unassisted from a low-temperature to a high-temperature substance [image downloaded Jan.25 2013 from http://summitjourneytowellness.blogspot.ca/2010/02/journey-to-wellness_5148.html ]

A. warm water to the red-hot thumbtack. Heat CHECK YOUR NEIGHBOR If a red-hot thumbtack is immersed in warm water, the direction of heat flow will be from the A. warm water to the red-hot thumbtack. red-hot thumbtack to the warm water. There will be no heat flow. Not enough information. B. red hot thumbtack to the warm water.

Quantity of heat Measured in joules or calories 4.18 joules of heat are required to change the temperature of 1 gram of water by 1 Celsius degree 4.18 joules = 1 calorie [photo by Scott Wallace, downloaded Jan.25 2013 from http://www.compadre.org/informal/index.cfm?Issue=11 ]

Quantity of Heat Energy ratings of foods and fuels are determined from energy released when they are burned. Unit of energy, the Calorie, is common for foods. kilocalorie or 1000 calories called a Calorie heat needed to change the temperature of 1 kg of water by 1C

Specific heat capacity Defined as the quantity of heat required to change the temperature of 1 kg of the substance by 1 degree Celsius Like thermal inertia—resistance of a substance to a change in temperature [image downloaded Jan.25 2013 from http://video.planetgreen.discovery.com/home-garden/hot-water-bottle-bed.html ]

Specific Heat Capacity Different substances have different thermal capacities for storing energy. Example: Takes about 2 minutes to raise the temperature of an iron pot of water to boiling temperature Takes less than 1 minute to raise the temperature of the same quantity of water in a silver pot to boiling temperature

Quantity of Heat CHECK YOUR NEIGHBOR The same quantity of heat is added to different amounts of water in two equal-size containers. The temperature of the smaller amount of water A. decreases more. increases more. does not change. Not enough information. B. increases more.

Quantity of Heat CHECK YOUR NEIGHBOR You heat a half-cup of tea and its temperature rises by 4C. How much will the temperature rise if you add the same amount of heat to a full cup of tea? A. 0C 2C 4C 8C B. 2C.

Specific Heat Capacities of Common Materials (kJ/kg °C) Alcohol 2.3 Aluminum 0.87 Ammonia 1.1 Brass 0.38 Brick 0.9 Cement 1.55 Chloroform 1.05 Citron Oil 1.84 Diamond 0.52 Ether 2.21 Freon 0.91 Gasoline 2.22 Glass 0.84 Glycerine 2.43 Material Specific Heat (kJ/kg °C) Gold 0.13 Hydrochloric acid 3.14 Iodine 2.15 Lava 0.84 Mercury 0.14 Milk 3.93 Olive oil 1.97 Paper 1.34 Plastic (hard) 1.67 Salt 0.88 Steel 0.49 Water 4.18 Wood 2 [solids data from http://www.engineeringtoolbox.com/specific-heat-solids-d_154.html ] [fluids data from http://www.engineeringtoolbox.com/specific-heat-fluids-d_151.html ]

The high specific heat capacity of water has higher capacity for storing energy than almost any other substance. involves various ways that energy can be absorbed. increases the jiggling motion of molecules, which raises the temperature increases the amount of internal vibration or rotation within the molecules, which becomes potential energy and doesn’t raise temperature water molecules can absorb energy without increasing translational kinetic energy

Which has the higher specific heat capacity, water or land? CHECK YOUR NEIGHBOR Which has the higher specific heat capacity, water or land? A. Water Land Both of the above are the same. None of the above. A. Water.

Thermal expansion Due to rise in temperature of a substance, molecules jiggle faster and move farther apart. Most substances expand when heated and contract when cooled. Railroad tracks laid on winter days expand and can buckle in hot summer. [image downloaded Jan. 25 2013 from http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/jarlid.html ] Warming metal lids on glass jars under hot water loosens the lid by more expansion of the lid than the jar.

Thermal expansion Plays a role in construction and devices. Example: Use of reinforcing steel with the same rate of expansion as concrete—expansion joints on bridges. Gaps on concrete roadways and sidewalks allow for concrete expansion in the summer and contraction in the winter.

Thermal expansion Different substances expand at different rates. Example: When the temperature of a bimetallic strip of brass and iron is increased, greater expansion occurs for the brass strip, which bends to turn a pointer, to regulate a valve, or to close a switch. Bimetallic strips are used in heaters, oven thermometers, refrigerators, and electric toasters.

Thermal Expansion: watch out! Increases in expansion are greater in liquids than in solids. Example: Overflow of gasoline from a car’s tank on a hot day Reason: Gasoline underground is cool, but when placed in the car’s tank, it warms and expands.

Thermal Expansion The metal in a metal ring expands. So the ring will get thicker and longer – more circumference, so larger. All linear dimensions of an object expand if the temperature increases: outer diameter, and inner diameter of ring. Also the inner diameter of a metal jar lid expands when it is heated!

Thermal Expansion: The exception to the rule Expansion of water to ice When water becomes ice, it expands! Ice has open-structured crystals resulting from strong bonds at certain angles that increase its volume. This make ice less dense than water.

When a sample of 0C water is heated, it first Thermal Expansion CHECK YOUR NEIGHBOR When a sample of 0C water is heated, it first A. expands. contracts. remains unchanged. Not enough information. B. contracts.

Thermal expansion of water When water freezes to become ice, its volume increases tremendously. As ice cools further, it contracts. Density of ice at any temperature is much lower than the density of water, which is why ice always floats on water.

Have a Great Reading Week! When we next meet on Monday Feb. 25, we will discuss Chapter 16, all about heat and heat transfer methods. Please read Chapter 16, or at least watch the 10-minute pre-class video for class 12. Something to think about: Psy likes to drink his coffee hot, and he likes cream in his coffee. He buys it at Starbucks but does not want to drink it until he gets to his home, which is a 5 minute walk. To keep the coffee as hot as possible, should he add the cream at Starbucks or at home?