Temperature

General physics

🎯 Learning Objectives

14.1.1 Understand that (thermal) energy is transferred from a region of higher temperature to a region of lower temperature.
14.1.2 Understand that regions of equal temperature are in thermal equilibrium.
14.2.1 Understand that a physical property that varies with temperature may be used for the measurement of temperature and state examples of such properties, including the density of a liquid, volume of a gas at constant pressure, resistance of a metal, and e.m.f. of a thermocouple.

🗣️ Language Objectives

Define thermal equilibrium, temperature, and thermal energy using precise scientific language.
Explain the direction of thermal energy transfer.
Describe how different physical properties can be used for temperature measurement.
Discuss the concept of an empirical temperature scale.

🔑 Key Terms / Негізгі терминдер / Ключевые термины

English Term	Русский перевод	Қазақша аудармасы
Thermal Energy	Тепловая энергия	Жылу энергиясы
Temperature	Температура	Температура
Heat	Теплота (Тепло)	Жылу
Thermal Equilibrium	Тепловое равновесие	Жылулық тепе-теңдік
Transfer	Передача	Тасымалдау, беру
Region	Область (Регион)	Аймақ
Physical Property	Физическое свойство	Физикалық қасиет
Thermometric Property	Термометрическое свойство	Термометрлік қасиет
Density	Плотность	Тығыздық
Volume	Объем	Көлем
Pressure	Давление	Қысым
Resistance	Сопротивление	Кедергі
Electromotive force (e.m.f.)	Электродвижущая сила (ЭДС)	Электр қозғаушы күш (ЭҚК)
Thermocouple	Термопара	Терможұп
Calibration	Калибровка	Калибрлеу
Fixed Points	Фиксированные точки (Реперные точки)	Тұрақты нүктелер (Реперлік нүктелер)

🃏 Flashcards for Practice

Review the key terms using flashcards. You can find relevant sets on Quizlet or create your own:

Search for «Thermal Equilibrium & Temperature» flashcards on Quizlet

Focus on understanding the definition and application of each term.

📖 Glossary / Глоссарий

Thermal Energy: The internal energy of an object due to the kinetic energy of its atoms and/or molecules. The hotter an object, the more thermal energy it has.
Translation (Қазақша)
Нысанның атомдарының және/немесе молекулаларының кинетикалық энергиясына байланысты ішкі энергиясы. Нысан неғұрлым ыстық болса, соғұрлым оның жылу энергиясы көп болады.
Temperature: A measure of the average kinetic energy of the particles in a substance. It indicates the degree of hotness or coldness of an object. It is a scalar quantity.
Translation (Қазақша)
Зат бөлшектерінің орташа кинетикалық энергиясының өлшемі. Ол нысанның ыстықтық немесе суықтық дәрежесін көрсетеді. Бұл скаляр шама.
Heat: The transfer of thermal energy between objects due to a temperature difference. Heat always flows from a region of higher temperature to a region of lower temperature.
Translation (Қазақша)
Температура айырмашылығына байланысты нысандар арасындағы жылу энергиясының тасымалдануы. Жылу әрқашан температурасы жоғары аймақтан температурасы төмен аймаққа қарай ағады.
Thermal Equilibrium: A state in which there is no net flow of thermal energy between two or more objects in thermal contact. This occurs when the objects are at the same temperature.
Translation (Қазақша)
Жылулық байланыстағы екі немесе одан да көп нысандар арасында таза жылу энергиясының ағыны болмайтын күй. Бұл нысандар бірдей температурада болғанда пайда болады.
Thermometric Property: A physical property of a substance that changes continuously and measurably with temperature, making it suitable for use in a thermometer.
Translation (Қазақша)
Заттың температураға байланысты үздіксіз және өлшенетіндей өзгеретін физикалық қасиеті, бұл оны термометрде қолдануға жарамды етеді.
Fixed Points: Reproducible temperatures used to calibrate a thermometer, such as the melting point of pure ice and the boiling point of pure water at standard atmospheric pressure.
Translation (Қазақша)
Термометрді калибрлеу үшін қолданылатын, стандартты атмосфералық қысымда таза мұздың еру нүктесі және таза судың қайнау нүктесі сияқты қайталанатын температуралар.

🔬 Theory: Thermal Equilibrium and Temperature / Теория: Жылулық тепе-теңдік және Температура

1. Thermal Energy and Temperature

All matter is made up of tiny particles (atoms and molecules) that are in constant random motion. This motion gives them kinetic energy. Thermal energy is the total internal energy of an object associated with the kinetic energies of its constituent particles. The more the particles move or vibrate, the higher the thermal energy.

Temperature is a measure of the average kinetic energy of these particles. It tells us how ‘hot’ or ‘cold’ an object is. When you touch a hot object, the fast-moving particles in the hot object transfer energy to the slower-moving particles in your hand, making your hand feel warm. Temperature is a fundamental physical quantity and is measured in Kelvin (K) in the SI system, although Celsius (°C) is also commonly used.

2. Transfer of Thermal Energy (Heat)

When two objects (or regions of the same object) at different temperatures are in thermal contact, thermal energy is transferred from the region of higher temperature to the region of lower temperature. This transfer of thermal energy due to a temperature difference is called heat. Heat is energy in transit; an object does not ‘contain’ heat, but it does contain thermal energy.

This energy transfer will continue until both objects reach the same temperature. There are three main mechanisms for heat transfer: conduction, convection, and radiation (which will be covered in more detail in other topics).

3. Thermal Equilibrium

When objects in thermal contact no longer have a net flow of thermal energy between them, they are said to be in thermal equilibrium. This occurs when they reach the same temperature. At thermal equilibrium, the rate of energy transfer from object A to object B is equal to the rate of energy transfer from B to A, resulting in no net change in their thermal energies.

The concept of thermal equilibrium is fundamental to the Zeroth Law of Thermodynamics, which states: If two thermodynamic systems are each in thermal equilibrium with a third one, then they are in thermal equilibrium with each other. This law allows us to define and measure temperature meaningfully.

4. Measuring Temperature and Thermometric Properties

To measure temperature, we use a thermometer. A thermometer relies on a thermometric property – a physical property of a substance that changes predictably and continuously with temperature. For a property to be useful for thermometry, it should:

Change continuously with temperature.
Change by a measurable amount over the desired temperature range.
Be reproducible (i.e., the same temperature always gives the same value of the property).
Have a unique value for each temperature.

Examples of physical properties used for temperature measurement include:

Density of a liquid: Most liquids expand when heated (density decreases). This is the principle behind liquid-in-glass thermometers (e.g., mercury or alcohol thermometers), where the volume (and thus length of the column) of the liquid changes with temperature.
Volume of a gas at constant pressure: According to Charles’s Law, the volume of a fixed mass of gas at constant pressure is directly proportional to its absolute temperature (V ∝ T). This is used in constant-pressure gas thermometers.
Resistance of a metal: The electrical resistance of a metal conductor typically increases as its temperature increases. This property is used in resistance thermometers (e.g., platinum resistance thermometers). The relationship is often linear over a small range: R_θ = R₀(1 + αθ), where R_θ is resistance at temperature θ, R₀ is resistance at 0°C, and α is the temperature coefficient of resistance.
Electromotive force (e.m.f.) of a thermocouple: A thermocouple consists of two different metals joined at two junctions. If the junctions are at different temperatures, a small e.m.f. (voltage) is produced, which varies with the temperature difference. This Seebeck effect is used in thermocouple thermometers, which are good for measuring a wide range of temperatures and rapidly changing temperatures.

To create a temperature scale, we need fixed points. These are easily reproducible temperatures, such as the ice point (0°C, the temperature of pure melting ice) and the steam point (100°C, the temperature of steam from pure water boiling at standard atmospheric pressure). The Celsius scale, for example, is defined by these two points.

Theory Translation (Қазақша)

1. Жылу энергиясы және Температура

Барлық заттар үнемі кездейсоқ қозғалыста болатын ұсақ бөлшектерден (атомдар мен молекулалар) тұрады. Бұл қозғалыс оларға кинетикалық энергия береді. Жылу энергиясы – бұл нысанның оны құрайтын бөлшектердің кинетикалық энергияларымен байланысты жалпы ішкі энергиясы. Бөлшектер неғұрлым көп қозғалса немесе тербелсе, жылу энергиясы соғұрлым жоғары болады.

Температура – осы бөлшектердің орташа кинетикалық энергиясының өлшемі. Ол бізге нысанның қаншалықты «ыстық» немесе «суық» екенін айтады. Сіз ыстық нысанға қол тигізгенде, ыстық нысандағы жылдам қозғалатын бөлшектер энергияны қолыңыздағы баяу қозғалатын бөлшектерге береді, бұл сіздің қолыңызды жылы сезінуге мәжбүр етеді. Температура – негізгі физикалық шама және SI жүйесінде Кельвинмен (К) өлшенеді, дегенмен Цельсий (°C) да жиі қолданылады.

2. Жылу энергиясының тасымалдануы (Жылу)

Әртүрлі температурадағы екі нысан (немесе бір нысанның әртүрлі аймақтары) жылулық байланыста болғанда, жылу энергиясы температурасы жоғары аймақтан температурасы төмен аймаққа тасымалданады. Температура айырмашылығына байланысты жылу энергиясының бұл тасымалдануы жылу деп аталады. Жылу – бұл транзиттегі энергия; нысанның «құрамында» жылу болмайды, бірақ оның құрамында жылу энергиясы болады.

Бұл энергия тасымалдануы екі нысан да бірдей температураға жеткенше жалғасады. Жылу тасымалдаудың үш негізгі механизмі бар: жылуөткізгіштік, конвекция және сәулелену (бұлар басқа тақырыптарда толығырақ қарастырылады).

3. Жылулық тепе-теңдік

Жылулық байланыстағы нысандар арасында енді таза жылу энергиясының ағыны болмаған кезде, олар жылулық тепе-теңдікте деп айтылады. Бұл олар бірдей температураға жеткенде болады. Жылулық тепе-теңдікте А нысанынан В нысанына энергия тасымалдау жылдамдығы В-дан А-ға энергия тасымалдау жылдамдығына тең болады, нәтижесінде олардың жылу энергияларында таза өзгеріс болмайды.

Жылулық тепе-теңдік ұғымы Термодинамиканың Нөлінші Заңының негізі болып табылады, ол былай дейді: Егер екі термодинамикалық жүйенің әрқайсысы үшіншісімен жылулық тепе-теңдікте болса, онда олар бір-бірімен жылулық тепе-теңдікте болады. Бұл заң температураны мағыналы түрде анықтауға және өлшеуге мүмкіндік береді.

4. Температураны өлшеу және Термометрлік қасиеттер

Температураны өлшеу үшін біз термометрді қолданамыз. Термометр термометрлік қасиетке – заттың температураға байланысты болжамды және үздіксіз өзгеретін физикалық қасиетіне сүйенеді. Бір қасиеттің термометрия үшін пайдалы болуы үшін ол келесідей болуы керек:

Температурамен үздіксіз өзгеруі.
Қажетті температура диапазонында өлшенетін мөлшерде өзгеруі.
Қайталанғыш болуы (яғни, бірдей температура әрқашан қасиеттің бірдей мәнін беруі).
Әрбір температура үшін бірегей мәнге ие болуы.

Температураны өлшеу үшін қолданылатын физикалық қасиеттердің мысалдары:

Сұйықтықтың тығыздығы: Көптеген сұйықтықтар қыздырғанда кеңейеді (тығыздығы азаяды). Бұл сұйықтықтық термометрлердің (мысалы, сынап немесе спирт термометрлері) принципі, мұнда сұйықтықтың көлемі (және осылайша бағанның ұзындығы) температурамен өзгереді.
Тұрақты қысымдағы газдың көлемі: Шарль заңына сәйкес, тұрақты қысымдағы белгілі бір массадағы газдың көлемі оның абсолютті температурасына тура пропорционал (V ∝ T). Бұл тұрақты қысымды газ термометрлерінде қолданылады.
Металлдың кедергісі: Металл өткізгіштің электрлік кедергісі әдетте оның температурасы артқан сайын артады. Бұл қасиет кедергілік термометрлерде (мысалы, платиналық кедергілік термометрлер) қолданылады. Байланыс көбінесе шағын диапазон үшін сызықтық болады: R_θ = R₀(1 + αθ), мұнда R_θ – θ температурадағы кедергі, R₀ – 0°C-тағы кедергі, ал α – кедергінің температуралық коэффициенті.
Терможұптың электр қозғаушы күші (ЭҚК): Терможұп екі түйіспеде біріктірілген екі түрлі металдан тұрады. Егер түйіспелер әртүрлі температурада болса, температура айырмашылығына байланысты өзгеретін шағын ЭҚК (кернеу) пайда болады. Бұл Зеебек эффектісі температуралардың кең ауқымын және тез өзгеретін температураларды өлшеуге жақсы келетін терможұп термометрлерінде қолданылады.

Температуралық шкаланы құру үшін бізге тұрақты нүктелер қажет. Бұлар оңай қайталанатын температуралар, мысалы, мұз нүктесі (0°C, таза еритін мұздың температурасы) және бу нүктесі (100°C, стандартты атмосфералық қысымда қайнаған таза судан шыққан будың температурасы). Мысалы, Цельсий шкаласы осы екі нүктемен анықталады.

Questions on Theory:

Easy: What happens to thermal energy when a hot object is placed in contact with a cold object?
Answer
Thermal energy is transferred from the hot object to the cold object until both reach the same temperature (thermal equilibrium).
Medium: Explain what is meant by ‘thermal equilibrium’ and why it is important for defining temperature.
Answer
Thermal equilibrium is the state where there is no net flow of thermal energy between objects in thermal contact, meaning they are at the same temperature. It’s important because the Zeroth Law of Thermodynamics, which is based on thermal equilibrium, allows us to define and consistently measure temperature. If object A is in thermal equilibrium with object C, and object B is also in thermal equilibrium with C, then A and B are in thermal equilibrium with each other (and thus at the same temperature as C and each other).
Medium: List three different physical properties that can be used for measuring temperature and give an example of a thermometer that uses each.
Answer
1. Volume of a liquid: Used in liquid-in-glass thermometers (e.g., mercury or alcohol thermometer).
2. Electrical resistance of a metal: Used in resistance thermometers (e.g., platinum resistance thermometer).
3. E.m.f. of a thermocouple: Used in thermocouple thermometers.
(Other examples: Volume of a gas at constant pressure — Constant-pressure gas thermometer; Pressure of a gas at constant volume — Constant-volume gas thermometer).
Hard (Critical Thinking): A student suggests using the color of a heated metal bar as a thermometric property. Discuss the advantages and disadvantages of this approach for creating a precise thermometer.
Answer
Advantages:
1. Visual and Non-contact: The color change is visually observable and can be assessed from a distance, which is useful for very hot objects where contact thermometry is difficult or dangerous.
2. Qualitative Indication: It provides a rough qualitative indication of temperature (e.g., dull red, cherry red, orange, yellow, white as temperature increases).
Disadvantages:
1. Subjectivity and Precision: Judging color accurately is subjective and difficult to quantify precisely. Different observers might perceive colors slightly differently, leading to inconsistent readings. It’s hard to create a continuous, precise scale.
2. Limited Range: Significant color changes only occur at relatively high temperatures. It wouldn’t be useful for measuring everyday temperatures (e.g., room temperature, body temperature).
3. Material Dependent: The exact color-temperature relationship depends on the material of the bar and its surface conditions (e.g., oxidation).
4. Calibration Difficulty: Calibrating such a «thermometer» against standard fixed points to create a reliable quantitative scale would be very challenging. It’s hard to assign specific numerical temperature values to subtle shades of color.
5. Influence of Ambient Light: The perceived color can be affected by the ambient lighting conditions.
Overall, while the color of a heated metal bar gives a rough idea of its temperature, it’s not suitable for precise, quantitative thermometry due to issues with objectivity, precision, range, and calibration. Pyrometers work on a related principle (intensity of radiation at specific wavelengths) but use sophisticated sensors, not just visual color.

🧠 Exercises on Memorizing Terms

Activity 1: Match the Term to its Definition

Match the terms on the left with their correct definitions on the right.

Terms:
1. Temperature
2. Thermal Equilibrium
3. Heat
4. Thermometric Property
5. Fixed Points

Definitions:
A. The transfer of thermal energy due to a temperature difference.
B. Reproducible temperatures used for thermometer calibration.
C. A measure of the average kinetic energy of particles in a substance.
D. A state of no net flow of thermal energy between objects in contact.
E. A physical property that varies consistently with temperature.

Answers for Activity 1

1. Temperature — C. A measure of the average kinetic energy of particles in a substance.
2. Thermal Equilibrium — D. A state of no net flow of thermal energy between objects in contact.
3. Heat — A. The transfer of thermal energy due to a temperature difference.
4. Thermometric Property — E. A physical property that varies consistently with temperature.
5. Fixed Points — B. Reproducible temperatures used for thermometer calibration.

Activity 2: Fill in the Blanks

Complete the sentences below using the key terms from the lesson:

Thermal energy always flows from a region of ______________ temperature to a region of ______________ temperature.
When two objects are at the same temperature, they are said to be in ______________ ______________.
The volume of a liquid, the resistance of a metal, and the e.m.f. of a thermocouple are all examples of ______________ ______________.
A thermometer is calibrated using ______________ ______________ such as the melting point of ice.
______________ is a measure of the degree of hotness or coldness of an object.

Answers for Activity 2

higher, lower
thermal equilibrium
thermometric properties
fixed points
Temperature

📺 Watch & Learn: Video on Thermal Equilibrium & Temperature

This video provides a visual explanation of thermal equilibrium and temperature:

Further Viewing — Related Topics:

📝 Solved Examples / Есептерді шешу мысалдары

Example 1: Direction of Energy Transfer

A block of copper at 80°C is placed in thermal contact with a block of aluminium at 20°C in an insulated container.

(a) In which direction will thermal energy be transferred between the blocks?

(b) What condition will be met when the blocks reach thermal equilibrium?

Brief Solution (Example 1)Detailed Solution (Example 1)

(a) From the copper block (80°C) to the aluminium block (20°C).

(b) Both blocks will be at the same temperature. There will be no net flow of thermal energy between them.

(a) Direction of thermal energy transfer:

Thermal energy is always transferred from a region of higher temperature to a region of lower temperature. Since the copper block is at 80°C (higher temperature) and the aluminium block is at 20°C (lower temperature), thermal energy will be transferred from the copper block to the aluminium block.

(Textual pronunciation: Thermal energy will be transferred from the copper block to the aluminium block.)

(b) Condition for thermal equilibrium:

The blocks will reach thermal equilibrium when there is no longer any net flow of thermal energy between them. This occurs when both the copper block and the aluminium block attain the same final temperature.

(Textual pronunciation: Both blocks will attain the same final temperature.)

The final temperature will not necessarily be exactly 50°C (the average of the initial temperatures). The final equilibrium temperature depends on the amount of thermal energy lost by the copper block and gained by the aluminium block. This, in turn, depends on the mass (m) of each block and the specific heat capacity (c) of copper and aluminium (Q = mcΔT). If the blocks have different masses or different specific heat capacities, the temperature changes will not be symmetrical, and the final temperature will not be the simple average. For example, if the aluminium block has a much larger mass and/or specific heat capacity, it will require more energy to raise its temperature by one degree Celsius compared to the copper block, so the final temperature might be closer to 20°C than to 80°C, or vice-versa.

(Textual pronunciation: The final temperature will not necessarily be exactly fifty degrees Celsius. It depends on the mass and specific heat capacity of each block.)

Example 2: Thermometric Property — Resistance Thermometer

The resistance of a platinum wire is used as a thermometric property. At the ice point (0°C), its resistance is 10.00 Ω. At the steam point (100°C), its resistance is 13.85 Ω. Assume the resistance varies linearly with temperature between these points.

(a) Determine the temperature when the resistance of the wire is 12.50 Ω.

(b) What is the resistance of the wire at 50°C?

Brief Solution (Example 2)Detailed Solution (Example 2)

(a) Temperature ≈ 64.94 °C

(b) Resistance at 50°C = 11.925 Ω

Let R_θ be the resistance at temperature θ°C, R₀ be the resistance at 0°C, and R₁₀₀ be the resistance at 100°C.

Given: R₀ = 10.00 Ω, R₁₀₀ = 13.85 Ω.

Since the resistance varies linearly with temperature, we can use the formula for a straight line, or more specifically for a linear thermometric property:

θ / 100 = (R_θ — R₀) / (R₁₀₀ — R₀)

(a) Determine the temperature when R_θ = 12.50 Ω.

Substitute the known values into the formula:

θ / 100 = (12.50 Ω — 10.00 Ω) / (13.85 Ω — 10.00 Ω)

θ / 100 = (2.50 Ω) / (3.85 Ω)

θ / 100 = 0.64935

θ = 0.64935 × 100

θ = 64.935 °C ≈ 64.94 °C (to 2 decimal places)

(Textual pronunciation: Theta divided by one hundred equals R theta minus R zero, all divided by R one hundred minus R zero. Substituting values: theta divided by one hundred equals twelve point five zero minus ten point zero zero, all divided by thirteen point eight five minus ten point zero zero. This simplifies to theta divided by one hundred equals two point five zero divided by three point eight five, which is zero point six four nine three five. So, theta equals sixty-four point nine three five degrees Celsius.)

(b) What is the resistance of the wire at θ = 50°C?

Rearrange the formula to solve for R_θ or use the same formula:

50 / 100 = (R₅₀ — 10.00) / (13.85 — 10.00)

0.50 = (R₅₀ — 10.00) / 3.85

Multiply by 3.85:

0.50 × 3.85 = R₅₀ — 10.00

1.925 = R₅₀ — 10.00

Add 10.00:

R₅₀ = 1.925 + 10.00

R₅₀ = 11.925 Ω

(Textual pronunciation: Fifty divided by one hundred equals R fifty minus ten point zero zero, all divided by three point eight five. So, zero point five zero equals R fifty minus ten point zero zero, divided by three point eight five. Multiplying by three point eight five gives one point nine two five equals R fifty minus ten point zero zero. Adding ten point zero zero, R fifty equals eleven point nine two five ohms.)

💻 Investigation Task: Energy Forms and Changes Simulation / Зерттеу тапсырмасы: Энергия түрлері және өзгерістері симуляциясы

Explore how energy is transferred and how temperature changes using the PhET Interactive Simulation «Energy Forms and Changes».

Link to Simulation: PhET Energy Forms and Changes Simulation

Instructions:

Open the simulation and select the «Intro» or «Systems» tab. We’ll use «Intro» for simplicity first.
Place an iron block and a brick block on the stands.
Check the «Energy Symbols» box to visualize thermal energy.
You can heat or cool the blocks using the sliders underneath them. Observe the change in energy symbols (representing thermal energy) and the thermometer readings.

Tasks:

Task 1: Heat the iron block significantly. Observe its thermometer and energy symbols. Now, place the hot iron block next to the cold brick block (or vice-versa, cool one block and heat the other, then put them in contact if the simulation allows direct contact or if you use the «Systems» tab with water between them). What happens to the energy symbols in both blocks over time? What happens to their temperatures?
Task 2: In the «Systems» tab, place water in the beaker. Add the iron block and heat it. Observe the temperature of the water and the iron. What happens to the energy transfer when both reach the same temperature?
Task 3: How does this simulation demonstrate the concept of thermal energy transfer and the approach to thermal equilibrium?

Brief Answers & Observations

Task 1 Answer (Contact & Energy Transfer):

When the hot iron block is placed near/in contact with the cold brick block (or energy is allowed to transfer between them), energy symbols (thermal energy) will be seen moving from the hotter iron block to the colder brick block.
The temperature of the iron block will decrease, and the temperature of the brick block will increase.
Over time, the net transfer of energy symbols will slow down as their temperatures get closer.

(Қазақша: Ыстық темір блок суық кірпіш блокпен жанасқанда/жақындасқанда (немесе олардың арасында энергия алмасуына мүмкіндік берілгенде), энергия белгілері (жылу энергиясы) ыстығырақ темір блоктан суығырақ кірпіш блокқа қарай жылжитыны байқалады. Темір блоктың температурасы төмендейді, ал кірпіш блоктың температурасы артады. Уақыт өте келе, олардың температуралары жақындаған сайын энергия белгілерінің таза тасымалдануы баяулайды.)

Task 2 Answer (Water & Iron in Systems Tab):

When the heated iron block is placed in the water, thermal energy transfers from the iron to the water. The iron’s temperature decreases, and the water’s temperature increases.
When both the iron and the water reach the same temperature (thermal equilibrium), the net transfer of thermal energy stops. Energy symbols might still move between them, but the rate of transfer from iron to water will equal the rate from water to iron.

(Қазақша: Қыздырылған темір блок суға салынғанда, жылу энергиясы темірден суға тасымалданады. Темірдің температурасы төмендейді, ал судың температурасы артады. Темір мен су бірдей температураға жеткенде (жылулық тепе-теңдік), жылу энергиясының таза тасымалдануы тоқтайды. Энергия белгілері олардың арасында әлі де қозғалуы мүмкін, бірақ темірден суға тасымалдау жылдамдығы судан темірге тасымалдау жылдамдығына тең болады.)

Task 3 Answer (Demonstration of Concepts):

The simulation demonstrates thermal energy transfer by showing energy symbols moving from hotter objects/regions to colder ones.
It demonstrates the approach to thermal equilibrium by showing that this net transfer continues until the objects reach the same temperature, at which point the thermometers show equal readings and the net flow of energy symbols ceases or balances out. The amount of energy symbols in each object then remains relatively constant (ignoring losses to surroundings if any).

(Қазақша: Симуляция жылу энергиясының тасымалдануын энергия белгілерінің ыстығырақ нысандардан/аймақтардан суығырақтарына қарай қозғалуын көрсету арқылы көрсетеді. Ол жылулық тепе-теңдікке жақындауды осы таза тасымалдаудың нысандар бірдей температураға жеткенше жалғасатынын көрсету арқылы көрсетеді, сол кезде термометрлер бірдей көрсеткіштерді көрсетеді және энергия белгілерінің таза ағыны тоқтайды немесе теңеседі. Содан кейін әр нысандағы энергия белгілерінің мөлшері салыстырмалы түрде тұрақты болып қалады (егер бар болса, қоршаған ортаға кететін шығындарды ескермегенде).)

🤝 Pair/Group Work: Concept Challenge / Жұптық/Топтық жұмыс: Түсініктер сайысы

Work with a partner or in a small group for this activity.

Option 1: LearningApps.org Activity

Go to the following LearningApps.org activity to test your understanding of temperature and heat concepts:

Temperature and Heat — Matching Activity (Note: This is a general concepts matching game, focus on the parts relevant to today’s lesson).

Alternatively, try this one on heat transfer: Heat Transfer Methods

Discuss your answers with your partner(s) and clarify any concepts you are unsure about.

Option 2: «Explain It!» Challenge

In your group, assign one person to explain each of the following concepts to the others without looking at their notes. The listeners can ask clarifying questions.

The difference between thermal energy and temperature.
What it means for two objects to be in thermal equilibrium.
How the resistance of a metal can be used as a thermometric property.
Why fixed points are necessary for calibrating a thermometer.

Rotate roles for each concept.

✍️ Individual Work: Structured Questions / Жеке жұмыс: Құрылымдық сұрақтар

Answer the following questions to test your understanding and ability to apply the concepts of thermal equilibrium and temperature. Show your working where necessary.

A student has two beakers of water. Beaker A contains 100 g of water at 20°C and Beaker B contains 200 g of water at 20°C.
(a) Compare the average kinetic energy of water molecules in Beaker A and Beaker B. Explain your answer.
(b) Compare the total thermal energy of the water in Beaker A and Beaker B. Explain your answer.
(c) If the water from both beakers is mixed in a larger insulated container, what will be the final temperature? Explain why no net thermal energy transfer occurs after mixing, assuming no heat loss to the surroundings.
Explain the principle of a thermocouple thermometer. Include in your answer:
(i) What a thermocouple is made of.
(ii) The physical phenomenon responsible for its operation (name the effect).
(iii) Two advantages of using a thermocouple for temperature measurement compared to a liquid-in-glass thermometer.
The volume of a fixed mass of gas at constant pressure is used as a thermometric property. At 0°C, the volume is 273 cm³. At 100°C, the volume is 373 cm³.
(a) On a graph of Volume (y-axis) against Temperature in °C (x-axis), sketch the expected relationship, assuming it is linear.
(b) Determine the temperature in °C when the volume of the gas is 300 cm³.
(c) What theoretical temperature does this scale predict for zero volume of the gas? What is the significance of this temperature?
Describe the key characteristics that a physical property must have to be suitable for use as a thermometric property. For one of the following properties, discuss how well it meets these characteristics: (i) the length of a metal rod, (ii) the pressure of a fixed mass of gas at constant volume.
Two objects, X and Y, are placed in thermal contact inside an insulated box. Object X has a larger mass but a smaller specific heat capacity than object Y. Initially, object X is at 10°C and object Y is at 90°C.
(a) State the direction of net thermal energy transfer.
(b) Will the final equilibrium temperature be (i) less than 50°C, (ii) equal to 50°C, or (iii) greater than 50°C? Justify your answer qualitatively without calculation, by considering the meaning of specific heat capacity and the energy changes involved.
(c) Explain what «insulated box» implies for the total thermal energy of the system (X + Y).

(Note: These questions are designed for analysis and synthesis. Focus on clear explanations and accurate calculations.)

Answers to Selected Individual Work Questions (Guidance)

Guidance for Q1:

(a) Average KE is related to temperature. Since temperatures are equal, average KE is equal.

(b) Thermal energy depends on mass and average KE. Beaker B has more mass, so more total thermal energy.

(c) Final temperature will be 20°C. No net transfer because they are already at the same temperature (in thermal equilibrium with each other).

Guidance for Q3:

(b) Use linear relationship: (θ — 0) / (100 — 0) = (V_θ — V₀) / (V₁₀₀ — V₀). θ/100 = (300-273)/(373-273) => θ/100 = 27/100 => θ = 27°C.

(c) Extrapolating the linear graph to V=0 gives θ = -273°C. This is Absolute Zero on the Celsius scale (0 Kelvin), the theoretical temperature at which particles have minimum kinetic energy.

Guidance for Q5:

(a) From Y (90°C) to X (10°C).

(b) Specific heat capacity (c) is energy needed to raise temp of 1kg by 1K. Energy lost by Y = Energy gained by X. m_Yc_Y(90-T_f) = m_Xc_X(T_f-10). Since c_X < c_Y, for a given energy change, X will experience a larger temperature change than Y if masses were equal. If m_X is larger, it further complicates. However, Y has higher initial temperature and higher c. The final temperature will depend on the product mc (thermal mass). Without specific values, it’s hard to be exact, but if c_Y is significantly larger, it will resist temperature change more. If m_Xc_X < m_Yc_Y, then T_f might be closer to 90°C. If m_Xc_X > m_Yc_Y, then T_f might be closer to 10°C. The question is tricky without more info or if it implies something specific about the «larger mass» vs «smaller specific heat capacity». Let’s assume the product mc is what matters. If Y has a larger thermal mass (m_Yc_Y), the final temperature will be closer to Y’s initial temperature (i.e., > 50°C). If X has a larger thermal mass, it will be closer to X’s initial temperature (i.e., < 50°C).
Let's re-evaluate: Y is hotter and has a higher specific heat capacity. X is colder, has larger mass but smaller specific heat capacity.
Energy lost by Y = m_Yc_YΔT_Y. Energy gained by X = m_Xc_XΔT_X.
Since c_Y > c_X, Y resists temperature change more per unit mass.
If m_X is much larger than m_Y, then m_Xc_X could be greater than m_Yc_Y. In this case, the final temperature would be closer to X’s initial temperature (i.e., < 50°C).
If m_Xc_X is less than m_Yc_Y, then the final temperature would be closer to Y’s initial temperature (i.e., > 50°C).
The question is designed to make students think about both m and c. «Object X has a larger mass but a smaller specific heat capacity than object Y.»
Let’s consider an extreme: if c_X is very small, even with larger m_X, its thermal mass m_Xc_X could be smaller than m_Yc_Y (if m_Y is not too small and c_Y is large). In this case, T_f would be > 50°C.
Conversely, if m_X is very large, m_Xc_X could be larger than m_Yc_Y. In this case, T_f would be < 50°C.
The question is ambiguous without relative magnitudes. However, typically, if one object has a "larger" mass and the other a "larger" specific heat capacity, the effects can compete. Let's assume the question implies a scenario where the product mc needs to be considered.
If we assume "larger mass" for X significantly outweighs its "smaller specific heat capacity" such that m_Xc_X > m_Yc_Y, then the final temperature will be closer to 10°C, so (i) less than 50°C. This means X requires more energy for the same temperature rise than Y loses for the same temperature drop, or X’s temperature changes less for a given amount of energy compared to Y if their thermal masses were equal.
Let’s assume the intention is that the object with the larger thermal capacity (product of mass and specific heat capacity) will change temperature less.
If m_X is significantly larger, and c_X is only slightly smaller, m_Xc_X could be > m_Yc_Y. Then X changes temperature less, so final T is closer to 10°C.
If c_Y is significantly larger, and m_Y is not too small, m_Yc_Y could be > m_Xc_X. Then Y changes temperature less, so final T is closer to 90°C.
This is a common type of qualitative question. The object with the larger «thermal mass» (mc) will experience a smaller temperature change.
If m_Xc_X > m_Yc_Y, then |T_f — 10| < |90 — T_f|, meaning T_f is closer to 10°C. So T_f < 50°C.
If m_Xc_X < m_Yc_Y, then |T_f — 10| > |90 — T_f|, meaning T_f is closer to 90°C. So T_f > 50°C.
The phrasing «Object X has a larger mass but a smaller specific heat capacity than object Y» doesn’t definitively tell us about m_Xc_X vs m_Yc_Y.
However, if we consider «dominant» factors: if X’s «larger mass» is very significant, it will pull the temperature down. If Y’s «larger c» is very significant, it will keep the temperature up.
A common interpretation: if one factor is «larger» and the other «smaller», the outcome is ambiguous. But if the question expects a single answer, there might be a typical assumption. Let’s assume the question implies the product mc for X is greater. Then final T < 50°C.
Alternative: if X has larger mass, it "holds more particles". If it has smaller c, each particle needs less energy to warm up.
Let's assume the question implies that the overall capacity of X to absorb heat without large temperature change is greater due to its mass, despite smaller c. So, it will pull the average temperature down more. Thus, (i) less than 50°C.
Justification: The object with the larger product of mass and specific heat capacity (thermal capacity) will undergo a smaller change in temperature for a given amount of heat transferred. We need to compare m_Xc_X with m_Yc_Y. Since the question is qualitative, we infer. If X’s larger mass dominates its smaller c, then m_Xc_X > m_Yc_Y, meaning X changes temperature less than Y. Since Y is losing heat and X is gaining, if X changes temp less, the final temp will be closer to X’s initial temp. So, < 50°C.

(c) «Insulated box» implies no thermal energy is lost to the surroundings or gained from the surroundings. The total thermal energy of the system (X + Y) remains constant.

📚 Further Resources & Reading / Қосымша ресурстар және оқу материалдары

Save My Exams — Temperature & Thermal Equilibrium: Temperature & Thermal Equilibrium Notes
Save My Exams — Thermometry: Thermometric Properties & Scales
PhysicsAndMathsTutor — Thermal Physics: A-Level CIE Physics — Thermal Physics (Browse for relevant sections)
OpenStax University Physics — Temperature and Heat: Chapter 1.1: Temperature and Thermal Equilibrium and Chapter 1.2: Thermometers and Temperature Scales
HyperPhysics — Zeroth Law of Thermodynamics: HyperPhysics — Thermal Equilibrium and the Zeroth Law

🤔 Lesson Reflection / Сабақ бойынша рефлексия

Take a few moments to reflect on what you have learned in this lesson:

What is the most important condition for two objects to be in thermal equilibrium?
Can you explain, in your own words, why a physical property used for temperature measurement must change *continuously* with temperature?
Which of the thermometric properties discussed today do you think would be most suitable for measuring very rapidly changing temperatures, and why?
On a scale of 1 (Not at all understood) to 5 (Very well understood), how would you rate your current understanding of how thermal energy transfer leads to thermal equilibrium?
What is one question you still have about temperature or thermometric properties, or what is one concept you would like to explore further?

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I’ve included placeholders for image URLs and YouTube video URLs. You’ll need to replace `»https://youtu.be/NfEJUPnqxk0″` and similar placeholders with actual, valid URLs for the YouTube videos and images you wish to use. I’ve used some generic image URLs from `ibb.co` as examples for the solved problems, and a real PhET simulation link. The LearningApps links are also examples.

Remember to test these shortcodes within your WordPress environment to ensure they display as expected with your theme and any relevant plugins. The styling of the tooltips (`…`) is a basic suggestion; your WordPress theme or a custom CSS might offer better ways to style these.
I’ve also added some brief answers/guidance to the individual work questions within a spoiler for your reference. You might want to remove or modify this part for the student-facing version.
The YouTube video URLs I’ve put in are:
Main: `https://www.youtube.com/watch?v=g9LOhg6923g`
Related 1: `https://www.youtube.com/watch?v=x9Z2o4yYj0E`
Related 2: `https://www.youtube.com/watch?v=90Q1y3gD5Yw`
Related 3: `https://www.youtube.com/watch?v=7kyD4h90XkM`

Please replace these with your preferred videos if need