Thermal Definition and 1000 Threads

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. B

    How Much Work to Displace a Microtubule's Free End?

    A microtubule is 100 microns long. Take the young modulus as 1 GPa and the microtubule as a hollow cylinder with outer diameter of 12.5 nm and thickness 2.5nm. a) If one end of the microtubule is clamped down, and is the other end is free to wobble. Estimate the work that must be done to...
  2. M

    Starlite and thermal barrier fun

    Hello everyone, First up, I know nothing about physics or chemistry. That out of the way, let's begin. I recently read about a very interesting material called Starlite which is supposedly a remarkable thermal barrier but is presumed lost to the world because the inventor kept the formula...
  3. nmsurobert

    Thermal Equilibrium: Why Does Car Get Hotter Inside?

    So you take some boiling water and drop a metal cube into it and the cube will reach the temp of the water. Or you leave some hot water out on a desk and the water will eventually become room temperature, right? Then why, in the summer time, does the inside of the car get way hotter than the...
  4. UsamaHameed

    Thermal Stresses in the barrel of a tank

    I want to calculate the thermal stresses in the barrel of a tank. The barrel is smooth bore, auto-frettaged and chrome-platted. I want to know if the thermal stresses are small enough to be neglected and if not, then how can I find them? Relevant Equation: Thermal Stress= modulus * coefficient...
  5. N

    Schroeder: Intro to thermal physics, Diff. between editions?

    Hi, I'm facing a slight problem with getting a good version of the Schroeder: Introduction to thermal physics. According to my lecturer the newest 2013 international edition by Pearson (ISBN: 9781292026213) is not recommended, as it lacks some aspects. And anyway the course is built around the...
  6. Nathanael

    Linear coefficient of thermal expansion

    The "coefficient of linear expansion" (≡k) was defined in my book by the following relationship: ##\Delta L=Lk\Delta T## Where L is length and T is temperature I'm wondering, is this just an approximation? Because, if you were to increase the temperature by \Delta T and then calculate the new...
  7. M

    Spherical bubble rises to surface, Ideal Gas, Thermal Energy

    Homework Statement A spherical air bubble in a lake expands as it rises slowly to the surface. At the point it starts to rise, the pressure is 2.00 atm, the temperature of the water is 10.0 ∘C, and the radius of the bubble is 5.00 × 10^−3 m. At the surface, the pressure is 1.00 atm and the...
  8. W

    Poisson's ratio for a rigid rod

    I have a conceptual misunderstanding it seems. Poisson's ratio is the ratio of elastic strain deformation of the transverse and longitudinal components. That being said, if I were to induce thermal stress (heating up) to a rod by keeping its ends (longitudinal component) rigid, would there be a...
  9. M

    Heat Capacity and Thermal Equilibrium

    Homework Statement A 3.50-kg block of iron initially at 8.00 × 10^2 K is placed on top of a 6.25-kg block of copper initially at 4.00 × 10^2 K. Assume the blocks are thermally insulated from their surroundings but not from each other and that they constitute a closed system. How much energy is...
  10. H

    What is the fastest way to transfer thermal energy?

    The fastest way to transfer thermal energy would be through: A. Thermal radiation B. Thermal conduction C. Thermal convection D. Thermal induction I thought it would be thermal radiation, but my teacher said its conduction. Is he right? Please explain.
  11. S

    How Does Measuring Position Impact Speed Measurement Accuracy in a Pendulum?

    Homework Statement We have a pendulum in thermal balance with the surroundings - no damping. We measure the speed of the pendulum. The accuracy of each speed measurement is known. How does the accuracy of the speed change, if we decide also measure the position of the pendulum with accuracy 10%...
  12. M

    Temperature of gas and solid in thermal equilibrium

    Hello I got to thinking about temperature when i prepared a lecture for my high school class. For a monoatomic ideal gas the temperature is proportional with the average kinetic energy of the atoms. For a diatomc gas we also have rotational energy (vibrations assumed to be freezed out), and for...
  13. K

    Nuclear fission and nuclear to thermal energy conversion

    Homework Statement [/B] Suppose the main water pipe breaks in a nuclear power plant, shutting off the water flow. If the control rods fall immediately into place, stopping the chain reaction, is there still a problem? Yes, because radioactivity continues to create lots of thermal energy. (A)...
  14. N

    How can I calculate the temperature of a body between two thermal reservoirs?

    If I know the temperatures of the two thermal reservoirs (one hot, one cold), the area of contact between each reservoir and the body, and the coefficients of conduction, it seems like I should be able to calculate the equilibrium temperature of the body, but I can't seem to figure out how.
  15. P

    What is the block's displacement when it first comes to rest again?

    Homework Statement A block with mass m = 1.46 kg is attached to a spring with spring constant k = 52.0 N/m and negligible mass. The coefficient of kinetic friction between the block and the table is µk = 0.349. The block is displaced from its equilibrium position to the left by 0.203 m...
  16. davgonz90

    What Should I Look For In A Thermal Cycler?

    I'm going to purchase a thermal cycler in the next few days. What qualities should I look for? How much should I spend? This is going to be a personal investment, and I'll have it in my home for periodic experiments at my own amusement.
  17. J

    Electrical & Thermal Conductivities of Metals

    Hi, please could someone explain why silver is a better conductor than, say, copper. Is it due to the fact that it has more conduction electrons than copper? I can't seem to find a definitive answer online. Thanks for any guidance offered.
  18. SalfordPhysics

    Thermal Conductivity of Steel experiment

    1) PROBLEM: Task is to find the thermal conductivity of steel experimentally. I have conducted relevant experiments and I am trying to solve for the thermal conductivity (k) itself. My final however is ten times too large in size, and I am having trouble identifying where the error is coming...
  19. H

    Alternator for thermal generator (Coal-fired generator)

    I am doing a project on coal fired generator and I don't really know how my Alternator will work. I'm currently trying to use a 2 pole stator, 5 former making 1 pole, single phase alternator. These are the problems : how do I calculate/obtain the power rating of my alternator/ generator does the...
  20. T

    How Does Earth's Core Contribute to Surface Heat Compared to Solar Radiation?

    Homework Statement The temperature within the Earth's crust increases about 1.0 C∘ for each 30 m of depth. The thermal conductivity of the crust is 0.80 W/C∘⋅m. A)Determine the heat transferred from the interior to the surface for the entire Earth in 9.0h . B)Compare this heat to the amount of...
  21. S

    Wow much thermal energy was generated by friction?

    Homework Statement Suppose a car approaches a hill and has an initial speed of 116 km/h at the bottom of the hill. The driver takes her foot off of the gas pedal and allows the car to coast up the hill. Randomized Variablesvi = 116 km/h m = 780 kg h = 20.5 m a = 2.3 ° Part (a) If the car has...
  22. Amr Ali 33

    Hey i need some help in calculating the thermal efficiency of steam turbine

    guys i just wanted to know the formula by which i can calculate the thermal efficiency of a pass out steam turbine( a steam turbine with an extraction for process ) I've attached a simple diagram explaining my problem can anyone please help !
  23. gfd43tg

    Thermal conductivity of water increasing with temperature

    The thermal conductivity of most solids and liquids decreases with increasing temperature, but water is an anomaly because it actually increases with increasing temperature. I don't understand why though. I suppose it is something about the material itself and its hydrogen bonding, but not sure...
  24. T

    What is the relationship between heat and thermal energy?

    What is the relationship between heat and thermal energy?
  25. enorbet

    Odd Thermal Reaction of Coffee Grounds

    Greetings While on an elk hunting trip in the mountains we awoke to roughly 2 feet of snow. Everyone wanted coffee and nobody had brought any conventional coffee tools. A cowboy boiled water in an aluminum pot just dumped coffee grounds in the water. Naturally a lot of those grounds floated...
  26. J

    Thermal Equilibrium of Ice and Water: Solving for Final Temperature and State

    Two 50g ice cubes are dropped into 200g of water in a glass. The water was initially at a temperature of 25°C, and the ice came directly from the freezer at -15°C. Neglect the heat capacity of the glass and any heat transfer to the environment. What is the final temperature of the drink when it...
  27. A

    Thermal Expansion of a shrink-fit collar

    Looking for some information on how a shrink fit collar actually works. I get the basic principle that you heat it, it expands, fit the collar, let it cool and it contracts and grips as a collar. However, if you heat a material am I right in saying that it expands in all direction. If this is...
  28. M

    Comsol Mechanical Thermal Contact

    hi, can somebody pls help me with the model i have appended to this post? it is a simple thermal mechanical contact problem but i don't know what is wrong about it and why there is some errors in it after computing. thanks
  29. T

    Calculate Thickness of Oak Layer to Limit Heat Loss to 740kJ/hr in Door

    The information I am given is : a door has two steel layers both are .47 mm thick, the door itself is 725 mm by 1800mm. The question asks, how thick of a layer of wood (oak) would have to be put in the door to limit the heat loss to 740kJ per hour? Temp inside is 18C and outside is -20C All...
  30. D

    Thermal Conduction and Newton's Law of Cooling

    Fourier's law of thermal conduction states that \mathbf{j}=-k\nabla T, where \mathbf{j} is the heat flux. Integrating both sides of this equation over a closed surface gives the equation \frac{dQ}{dt}=-k\int \nabla T \cdot d\mathbf A. If there is a temperature discontinuity across this...
  31. K

    Thermal Elongation of 2 different rods

    Homework Statement A metal rod of length 30 cm elongates 0.075 cm when heated from 00C to 1000C. a second rod of the same length but from an other metal elongates, at the same temperature difference, 0.045 cm. A third rod is made of 2 pieces from the 2 previous ones and of the same length...
  32. K

    Thermal elongation-ring on a shaft

    Homework Statement A steel ring has a diameter of 75 mm at 20 deg C. how much must it be heated in order to mount on a brass shaft of dia 75.05 Then both are cooled. how must they be cooled so the ring will fall off? Homework Equations Thermal elongation coefficient of steel: 12E-6 Thermal...
  33. C

    Heat sensitive ion channels for thermal imaging?

    To the best of my knowledge, thermal imaging (with a thermograph as the end results) is performed using arrays of thermopiles. This can become hugely expensive and is the reason fire services sometimes have trouble affording thermal imaging cameras. Snakes have heat sensitive ion channels...
  34. K

    Correct Distance of 28.856m between 2 Points at 350°C

    Homework Statement A steel ruler is correct at 180c. when the temperature was 350c a distance of 28.85 m was measured between 2 points. what is the correct distance Homework Equations $$L=L_0(1-\alpha \Delta t)$$ The Attempt at a Solution $$1+12E-6 \cdot 17^0=1.000204$$ How many big...
  35. D

    Thermal expansion/contraction of lens

    Application: to measure the thermal strain of optical lens. Due to temperature variation the lens surface is expanding / contracting in radial direction with two extreme operating temperature. (-40C to +70C ) Optical lens is SF56A (CTE - 7.9*e-6 per Kelvin) What to do: I need to measure...
  36. K

    Thermal Elongation of Alumina: 0.00036

    Homework Statement The pendulum of a clock is made of alumina. what is the relative elongation when cooled from 750 fahrenheit to 450? Homework Equations $$L=L_0(1-\alpha \Delta t)$$ From Fahrenheit to Celsius: $$t_f=\frac{9}{5}t_c+32^0$$ Coefficient of thermal elongation of alumina...
  37. J

    Finding coefficient of thermal expansion

    Homework Statement "see attachment" "q1" Homework Equations V=\frac{-A}{r}+\frac{B}{r^{10}} A=5*10^-30 B=8*10^-121 V=potential energy r=interatomic separation distance Coefficient of thermal expansion = \frac{change in L}{L*change in T} The Attempt at a Solution I have...
  38. svenskaTom

    Using E=mc^2 does thermal energy add to an object's mass?

    Hi everybody, I hope this is the appropriate place to post this question: A middle school physics book here in Sweden poses this question after giving a brief explanation of E = mc2: For you Swedish speakers here is the original text: So my answer is "Yes" to both since the additional...
  39. R

    Finding thermal conductivity of an insulated metal bar

    Homework Statement One end of an insulated metal rod is maintained at 100∘C and the other end is maintained at 0.00 ∘C by an ice–water mixture. The rod has a length of 60.0cm and a cross-sectional area of 1.40cm2 . The heat conducted by the rod melts a mass of 7.15g of ice in a time of 15.0min...
  40. M

    Finding thermal conductivity with conduction and convection.

    Homework Statement Determine the thermal conductivity of a metal (assume linear heat distribution at steady-state, and well insulated), given, Thot = 96.8 Tcold = 29.5 There is also: 13.7 W being pumped in at one end. Water convecting heat away on the other end. Homework Equations...
  41. D

    Calculate Energy Applied to Steel Slab

    I want to calculate the energy applied to a slab of steel with a temperature rise that varying with time (t) as - 13t + 5t^2 + 10* sin (3ωt) The energy applied to the system is calculated by mc (dT) equation where m mass of the slab c specific heat dT change in temperature
  42. S

    Thermal expansion of a copper pipe

    Homework Statement Many hot-water heating systems have a reservoir tank connected directly to the pipeline, so as to allow for expansion when the water becomes hot. The heating system of a house has 63.1 m of copper pipe whose inside radius is 7.69 x 10^-3 m. When the water and pipe are heated...
  43. F

    Secondary thermal energey conversion to inertial energy.

    is it possible by any means to use a type of resonance wave to convert the vibrating motion of molecules in an object such that they start moving in the same direction causing the object to take off at high speed once the majority of the molecules are moving in the same direction? the...
  44. M

    Low Thermal Expansion Coefficient Glass Tube

    Hi All, I would like to ask if what supplier's fabricate Low Coefficient of Thermal Expansion (CTE) glass tubing for Fiber Optics application. or What type of glass do we need in Low CTE? It will serve as the packaging for DWDM components. Hoping for your response. Thank you.
  45. H

    Why Do Gases Need Same Speed for Thermal Equilibrium?

    When two gases are mixed, if they are to be in thermal equilibrium, they must have the same average molecular speed. Why or why not?
  46. M

    Is thermal energy a renewable or non-renewable energy?

    im not talking about geothermal energy because my teacher gave us topics and mine is thermal energy and i did some research but i still don't get it if its renewable or nonrenewable because i got mixed answers when i researched about it. and are there any advantages for this energy? i think...
  47. A

    Nonlinear conduction,where thermal conductivity depends on temparature

    Hi everyone, i am trying to solve and program a non linear differential equation in MATLAB where thermal conductivity depends on temparature.I am trying it to solve by explicit finite difference method. the given equation is ∂2t/∂x2+∂2t/∂y2 *k(t)= -q (x,y) i have solved the equation taking...
  48. K

    Thermal Hydraulic Calculations using NS

    Hi all I am very much a layman when it comes to Thermal Hydraulics and this may be a naive questions but here it goes... On the job, i use various codes to examine two phase flow in the core loop. Despite being vetted and validated numerous times over the course of many years (TRAC, RELAP...
  49. G

    Thermal management in satellites

    How effective are the thermal management techniques in satellites? What kind thermal loads can they support? And I take it that while conduction can be used to transfer heat from one area of the satellite to another, that the ultimate limiting factor is the amount that it can dissipate as radiation?
  50. B

    How to Import Ansoft Maxwell Model into ANSYS Workbench for Thermal Analysis?

    Hello, I have modell in Ansoft Maxwell sumulate and need to transfer (import) it in Workbench ANSYS for the next step (Thermal analysis). How can i import it? Thank.
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