What is Thermal: Definition and 1000 Discussions

A thermal column (or thermal) is a column of rising air in the lower altitudes of Earth's atmosphere, a form of atmospheric updraft. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example of convection, specifically atmospheric convection. The Sun warms the ground, which in turn warms the air directly above it. A thermal is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically.

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  1. T

    Derive thermal expansion of area from length

    I tried following: $$ \Delta l = \alpha l_0 \Delta T $$ $$ (\Delta l)^2 l_0 = \alpha l_0^2 \Delta T \Delta l $$ $$ \Delta A l_0 = \alpha A_0 \Delta T $$ $$ \Delta A = \frac{ \alpha A_0 \Delta T }{ l_0 } $$ If we remember that: $$ \Delta l = \alpha l_0 \Delta T $$ So we have $$ \Delta A = \frac{...
  2. W

    Thermal Physics: Fermi Gas and chemical potential

    Hi all, I have an issue trying to understand the following paragraph from Blundell's book. How, exactly, does the definition of ##\mu_0 = E_F## "make sense"? In the sentence after 30.21, it seems to say that the mean energy for a system with ##N## particles differs from that of a system with...
  3. V

    A CMB as thermal radiation of cosmic dust?

    Recently, the origin of the cosmic microwave background as a relic radiation of the Big Bang was questioned and an idea of the CMB as thermal radiation of cosmic dust was revived and revisited. Under this theory, the temperature of the cosmic dust is predicted to be 2.776 K which differs from...
  4. A. Neumaier

    I The thermal interpretation of quantum physics

    A complete description of the thermal interpretation of quantum physics can be found in my just finished papers (for the bare bones, see Section 2.5 of Part II) Foundations of quantum physics I. A critique of the tradition, Foundations of quantum physics II. The thermal interpretation...
  5. N

    Heat Recovery Potential from Domestic Boilers & Ovens

    Hi guys, I am currently exploring dissertation ideas and have been looking into the heat recovery potential from domestic gas boilers and ovens. More specifically, I am seeing if it is viable to collect heat from these appliances during or after their use, and then pump this heat into the attic...
  6. K

    Thermal Conductivity Problem-- Two Reservoirs

    Suppose that a large mixture of ice and water is in thermal contact with a reservoir which contains a large quantity of water and steam. Assume that both the ice/water bath and the water/steam reservoirs are otherwise thermally isolated and at a constant temperature. The only contact between...
  7. N

    Sophisticated Experiment (Thermal Conductivity of Housing Materials)

    Hi everyone, I am currently a third year University Student in the UK and I'm in the midst of doing my dissertation. My dissertation topic (Effective methods of decreasing the thermal Conductivity of Housing Materials) requires that I produce several experiments to test and analyse a certain...
  8. SebastianRM

    Intro to thermal Physics - D. V. Schroeder -Entropy question

    Hey guys, so I am reading this book and on pages 89-90, the author says: "Increasing temperature correspond to a decreasing slope on Entropy vs Energy graph", then a sample graph is provided, and both in that graph and in the numerical analysis given in page 87 the slope is observed to be an...
  9. W

    Thermal Physics: Reversible processes

    Hi all, I have been having some issues trying to show that a reversible expansion of gas does not create new entropy. Assistance is greatly appreciated! So suppose that a gas expands reversibly as shown below at fixed temperature At fixed temperature, internal energy doesn't change so...
  10. W

    Thermal Physics: Reaction problem

    Homework Statement Hi all, I am having issues with the following problem. Assistance is greatly appreciated! Homework EquationsThe Attempt at a Solution a) The "law of mass action" I know of is just the equilibrium constant, which I wrote in terms of partial pressures at equiilbrium $$K =...
  11. W

    Thermal Physics: Interpretation of equilibrium constant

    For a reaction defined as such, $$A\rightleftharpoons B$$ the equilibrium constant ##K## is defined by ##K = p_B / p_A##, with ##p## denoting the partial pressure (edit: at equilibrium). However, if ##K<<1##, which implies ##p_A >> p_B##, it is said that the backwards reaction dominates and that...
  12. W

    Question regarding Blundell: Concepts in Thermal Physics

    Hi all, I have an issue with understanding the following passage in the aforementioned book. I have uploaded the relevant passage as an image below. Any assistance is greatly appreciated! The paragraph under equation (22.57) says that the total Helmholtz function ##F## is a sum of Helmholtz...
  13. Sherlock01

    Need help with finding thermal and Kinetic energy

    Homework Statement A block starts at rest. A hand pushes the block with 6.1 N to the right across a rough surface, with 1.5 N of friction. if the block moves 1.6 m horizontally determine the following (a) work done by hand (b) work done by friction (c) the amount of thermal energy created (d)...
  14. D

    Intro Physics Undergraduate books for self-study (quantum and thermal physics)

    It's been a while since I studied physics. I did a few basic courses in physics as a freshman, but I never studied any physics since, but instead majored in math and ended up doing a math PhD. Nowadays, I work on self-driving cars at a large tech company, where my work is mostly in computer...
  15. sweet springs

    B Time Dilation and thermal motion

    [Mentors' note: This thread was split off from another thread about the cosmic ray muon measurements] The particle at rest in the moving ship is moving against the Earth. The particle at rest on the Earth is moving against the moving ship. A scientist in the moving ship measures the life time...
  16. W

    Heat bath and canonical ensembles

    Hi all, I have encountered the idea of a heat bath but am slightly perplexed as to what it is. There was a textbook example that looked to find the number density expression for gas molecules as a function of position (image below). It then said that the probability ##P(z)## of finding the...
  17. S

    Thermal expansion apparatus

    Homework Statement Im hoping that this experimental setup is common enough in 1st year physics that someone could at least point me in right direction because I may be misunderstanding how the arm and pointer connect together. I need to come up with an equation that relates how far the metal...
  18. Q

    Thermal Expansion (Area Expansion) problem help

    Homework Statement A steel ring with a hole having area of 3.990 cm2 is to be placed on an aluminum rod with crosssectional area of 4.000 cm2. Both rod and ring are initially at a temperature of 35.0°C. At what common temperature can the steel ring be slipped onto one end of the aluminum rod...
  19. P

    What exactly is the thermal lens effect?

    Hello, i just wanted to ask if you can explain to me what thermal lens effect is? I am supposed to answer why laser beam passing through ink or soy sauce creates this effect and i can't find any information on what actually this thermal lens is. I know of course that it is a lens, but why does...
  20. H

    Thermal efficiency of the Rankine cycle

    Homework Statement Calculate thermal efficiency of R-C cycle with saturated steam as shown in the picture. Steam has 4,5MPa when entering into HP part of the turbine (VT in the picture) and expansion on HP is finished at 0,3MPa. Moisture is then removed in the separator and steam is overheated...
  21. Clara Chung

    How to find the change from a differentials problem (thermal)

    How to get from 14.24 to 14.25?
  22. YC_128

    Thermal efficiency of the engine in a PV diagram

    A heat engine takes 2.0 moles of an ideal gas through the reversible cycle abca, on the pV diagram shown in the figure. The path bc is an isothermal process. The temperature at c is 820 K, and the volumes at a and c are 0.010 m3 and 0.16 m3, respectively. The molar heat capacity at constant...
  23. person123

    Thermal Expansion of a Wire Connected To a Rod

    Homework Statement Homework Equations ΔL=LαΔT σ=EΔL/L The Attempt at a Solution For part a, I used the coefficient of linear expansion for copper and the change in temperature to find the change in length (0.068%). I thought part b had the same answer. The two are attached, and I would...
  24. M

    Need help in thermodynamics: Calculations for a thermal cycle

    Homework Statement how to know the maximum and minimum temperature for cycle in. Carnot thermal efficiency 60% heat transfer during isothermal expansion 40kj pressure is 5.6bar and volume is 0.3m^3 Homework Equations One kilogram of air as an ideal gas executes a Carnot power cycle having a...
  25. Edge5

    The thermal speed of an electron at room temperature

    I am trying to find the thermal speed of electron at room temperature. kT = (1/2)mv^2 which gives v=√((2kT)/m) but answer says it should be √((kT)/m) Where did that 2 go?
  26. DariusP

    Why is there a temperature gradient in lasers causing thermal lensing?

    Hello, I wanted to ask about thermal lensing. Thermal lensing is when a temperature gradient from the center of the medium to the outermost part of the medium is created. This causes a varying refractive index throughout the medium. What I want to ask is: Why is the core of the rod(or any other...
  27. D

    Heating efficiency of a Heat Pump and a Space Heater

    Homework Statement Instead of pumping heat into the cabaret air from the outside air, you could simply put an electric space heater inside the cabaret. A space heater turns electrical energy directly into thermal energy. Why would operating a space heater consume more electric power than...
  28. D

    Heating a Cabaret during the winter

    Homework Statement During the winter, your climate control system must begin warming the cabaret air so that the cabaret air is hotter than outdoor air. Amazingly enough, it can do this relatively efficiently by transferring heat from the outside air into the cabaret. However, your system must...
  29. D

    Energy Efficient AC unit by returning air to the building

    Homework Statement You arrange your climate control system so that as it pumps heat out of the cabaret air and thereby chills and dries that air. Part of the heat your system removes from the cabaret air goes to the outdoor air and part goes back to the cabaret air. It turns out that delivering...
  30. D

    Thermal Energy when Heating and Cooling a Cabaret

    Homework Statement Having chilled the air until it contains only the perfect amount of moisture, you want to reheat it to the ideal cabaret temperature. You could use an electric space heater or wood fire, but you already have another source of heat: the same system that chilled the air in the...
  31. D

    Harnessing Energy in an Engine: Unlocking the Secrets of Thermodynamics

    Homework Statement You're in Paris, working on your first novel and short on cash. The owner of the cabaret downstairs has offered to take care of your rent if you'll help her design a climate control system for the place. It gets too hot and damp in the summer, and too cold and dry in the...
  32. DracoMalfoy

    Thermal physics phase change: Liquid copper to solid

    Homework Statement How much energy must be removed from the system to turn liquid copper of mass 1.5kg at 1083 degrees celsius to solid copper at 1000 degrees celsius? a. -2.49X10^5J b. -3.67X10^4J c. 2.25X10^3J d. 9.45X10^4J e. -2.78X10^3J Homework Equations Q=Mc(Tf-Ti)...
  33. Andrew Lewis

    Thermal Physics: Photon Statistics on Bose Particles

    Homework Statement [/B] I have solve the rest of this problem pretty easily and see no problems with working with Indistinguishable particles, Distinguishable particles, fermions and Bosons. Part c has me very confused though about what it is even asking. Suppose a system with equally spaced...
  34. R

    Temperature profiles and thermal resistance

    I heated two different materials with a laser beam for about 10 seconds and these are the measured temperature profiles: From the various solutions to the general heat conduction equation, temperature rise seems to increase with increasing thermal resistance of the material. The total...
  35. T

    Misc. Optimizing Thermal Management for Wooden Computer Cases: A Fan-Based Solution?

    I am working on a project; a computer case made out of wood, most likely oak. I was wondering if two fans (one bringing air in, on taking air out) would be enough to keep the system at a stable temperature. I wasnt sure because i know most cases are made of thin metal which conducts and...
  36. patrykh18

    Energy of a crystal in thermal equilibrium

    Homework Statement In a monatomic crystalline solid each atom can occupy either a regular lattice site or an interstitial site. The energy of an atom at an interstitial site exceeds the energy of an atom at a lattice site by an amount ε. Assume that the number of interstitial sites equals the...
  37. yecko

    Conduction with thermal energy generation

    Homework Statement I am wrong in my attempt, yet I can't figure out the reason why... Homework Equations (solution with h=250 W/m^2*K instead of 350 W/m^2*K) The Attempt at a Solution This is how I obtain the answers, which I checked all the calculations and I don't think there is...
  38. Stephen Lanford

    Possible error sources in thermal conductivity experiment?

    Hello, my name is Stephen Lanford and I am currently working on a Physics II lab. I am solving for the thermal conductivity of four materials (glass, plexiglass, pine, and sheetrock) using data from thermal conductivity experiments. The experiments consist of a steam chamber at 100 C, a block...
  39. almarpa

    Classical Complementary book for Schroeder's Thermal Physics

    Hello all. I am studying Thermal Physics from Schroeder's book. I really like this book, but the number of worked examples and solved problems is minimum. Could you please suggest me a complemetary book with worked examples and problems? The ideal book should be similar to Schroeder's, with the...
  40. TheSlovakEngineer

    Storing Energy as Heat in Vegetable Oil

    Hello, I am writing a blog article about storing solar energy as heat. Can someone credible check this? I calculated I need 185.4 liters of vegetable oil to substitute a 6.4kWh battery if I had the same energy conversion (Tesla says 90%) and energy loss over time (no idea about this value) as...
  41. Benhur

    Question about thermal radiation

    Hello everybody, I have a question about thermal radiation: Imagine a body at a certain temperature T, in an environment with nothing around it. Theoretically, this body emits radiation according to its temperature (the maximum radiation is described by the Wien relation); If it emits, it must...
  42. shahbaznihal

    A Thermal Field Theory: Calculating Angular Distribution of CMB

    What is the basic idea and purpose of the thermal field theory? I don't need a full in depth description of it, not at the moment at least. I am just trying to understand how it is relevant in the calculation of angular distribution of temperature of CMB(Comic Microwave Background) over the sky.
  43. katelr

    When/How does thermal radiation stop (if it stops) and conduction

    Consider two solid objects in the vacuum (of different materials, if you will) at different temperatures approaching each other until they make "perfect contact" through flat surfaces (no gaps or defects, so that thermal contact conductance effects are absent, even though interfacial thermal...
  44. H

    Thermal ballast (or whatever it's called)

    During weather-based heat waves or cold snaps, a completely sealed house with all windows/doors shut (but using no HVAC, heating-ventilation-AC) will take "a while" to cool down or heat up. If the heat wave or cold snap is quick (e.g., 24 hrs), a resident inside the house will experience almost...
  45. M

    Comparison of thermal shock profiles

    Could someone help me in comparing 2 different thermal shock test profiles effect on a component. The 2 profiles are varied in deg C /min change and also the dwell time in low and high tempwratures. Any references are highly appreciated. Thank you
  46. L

    What Happens to Water Temperature and State After Heating for 25 Minutes?

    A heater so P=500Js^-1,heats up a tank of water of 200ml from 25°C for 25 minutes. What is the final form(solid ,liquid or gas)and the final temperature of the water? The answer: Final form : Liquid+vapour Final temperature: 100°C I have no idea how to do this! Plz help!
  47. baldbrain

    Iron Ring Expansion: Solve for Δθ to Find Temp Increase

    Homework Statement An iron ring of radius 2.1 m is to be fitted on the rim of a wheel of radius 2.121 m. The coefficient of volume expansion for iron is 3.6 x 10-5 K-1. By how much should the temperature of the ring be increased? (a) 532 °C (b) 833 °C (c) 278 °C (d) 378 °C Homework Equations...
  48. sweet springs

    Exchanging roles of variable and thermal potential

    In thermal physics entropy S is regarded as a system variable in 1st theorem of thermal dynamics, i.e. dE(S,V)=TdS-pdV=T(S,V)dS-p(S,V)dV Entropy is regarded also as thermal potential,i.e. dS(E,V)=\frac{1}{T(E,V)}dE + \frac{p(E,V)}{T(E,V)}dV S,V,p,T are usually regarded as variables. My...
  49. Cassius1n

    Heat loss in a conductor based on Fourier's law

    Homework Statement Find the admissible current density Jadm for a wire that has no insulation and also for a wire that has two layers of insulation and compare it to Jadm for the case when the wire has only one layer of insulation.2. The attempt at a solution and equations In the image I've...
  50. H

    A Do thermal quantities change in quantum phase transition?

    Such as, Chern insulator, normal insulator, topological insulator, do they have any discontinuous change in thermal quantities? Do they have order parameters?
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