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.

View More On Wikipedia.org
Recent contents Top users
  1. C

    How to work out thermal diffusivity using Angstrom's method?

    Hi guys, Just looking for some help with the theory on a project I've been set at university. The experiment involved heating a long thin bar from one end with a sinusoidal heat wave. Thermocouples were then placed every 7 cm (4 in total) and temperatures were recorded. The experiment brief...
  2. L

    Thermal Conductivites between two dissimilar metals

    1. Homework Statement I've been failing to find examples dealing with "longitudinal" thermal conductivity and how two objects in contact with each other would affect the heat flow compared to not being in contact at all. Problem: Given the following information, determine the thermal energy...
  3. Lacplesis

    Diamond vs. glass -- thermal properties

    Hi, I was reading up on the properties on various materials but never quite found out what I was looking for. My question is this , I found out an explanation why diamond is the best thermal conductor even though its not a metal and why other materials that would be similar to diamond like glass...
  4. Kaneki123

    Two Questions about thermal radiation....

    Okay... I have two questions regarding thermal radiation...The first one is that, it is a constant fact that heat travels from hot to cold body, and all things give out thermal radiation, So arent these two facts contradictory in the sense that "everything is heating every other thing regardless...
  5. M

    Finding thermal expansion problems for measurement technique

    I am trying to find examples problems on thermal expasions related to the subject of measurement technique Google but I can't find them.. I don't know exactly what could be asked but the problem will be related to: "expansion of measurement device" is given, and "expansion of measured...
  6. Markus Lervik

    Thermal velocity of a soccer ball

    Hello, I am an IB HL Physics student. I am thinking of doing my IA on the thermal velocity of a soccer ball. I will be using a soccer ball shooter (machine) to simulate the thermal velocity. I have a couple of questions: what is the thermal velocity equation, which would fit for a soccer...
  7. nickyfernandezzz

    Kinetic energy to thermal energy

    Hey guys, I need help with the following question. A lead ball of specific heat capacity 130J/KgK travels with a speed of 100m/s before it hits a wooden cube fixed to floor and gets stuck inside.What will be the rise in temperature of this lead ball by the time it comes to I attempted the...
  8. BH1988

    Fe2O3 Thermal Decomposition Question

    Hi, I've been asked to heat a sample that contains Fe2O3, amongst some other things, to a temperature where Fe2O3 will decompose. I am unable to find the temperature at which I would need to heat the sample and I'm not entirely convinced this is actually possible with the equipment I have...
  9. N

    Thermal conductivity of a thin film

    Homework Statement The problem is given. Homework EquationsThe Attempt at a Solution I tried to solve the question as if there is a nanowire between two reservoirs and got an answer. But I don't know what should I do to measure thermal conductivity in a thin film. My formula for k in a...
  10. elixer akm

    Thermal vs Mech. Efficiency of Engines: Petrol vs Diesel

    What is the difference between thermal efficiency and mechanical efficiency of an engine...and which engine is more efficient ..petrol or diesel
  11. BrainMan

    Thermal Expansion Problem Involving a Brass Ring

    Homework Statement Homework Equations ΔL = LαΔT The Attempt at a Solution What I did was to set the diameter of the inside of the brass ring + the change in diameter of the brass ring equal to the diameter of the steel rod + change in the diameter of the steel rod. So, Lbrass + ΔLbrass =...
  12. yecko

    What is the Thermal Efficiency of an Engine?

    Homework Statement http://i.imgur.com/SQ6jx94.png (sorry for the low resolution~ it's already the best i can make it~) Homework Equations U=Q+W the three variables of isobaric, isochoric, adiabatic process (can i save my effort from typing all of them out?) e=(Qh-Qc)/Qh The Attempt at a...
  13. B

    Thermal expansion of a pipe with wall temperature gradient

    I have a pipe holding liquid at 80°C. The outside atmosphere is -2°C. The pipe gets a temperature gradient over the wall thickness. The outside fibers will thus restrain the inner fibers from expanding. I would like to know the increase in the inner dia of the pipe. I have found temperature...
  14. V

    Thermal coefficient of expansion in gases

    I know that the variation in a gas' volume is equal to ΔV = γ⋅V[initial]⋅ΔΘ with ΔΘ the variation in temperature and γ=1/237 the thermal coefficient of expansion in gases. Could someone please explain to me why γ=1/237 please ? Thanks a lot, V
  15. L

    Finding change in thermal energy Work and Energy problem

    Homework Statement A 26.2 kg child rides a 1.00 kg potato sack down a 2.05 m high slide. If the child starts from rest and has a speed of 1.60 m/s at the bottom of the slide, what is the change in thermal energy of the child on their potato sack and the slide? Homework Equations KE = (1/2)mv2...
  16. T

    Thermal Physics (Specific Heat Capacity)

    Homework Statement Body X whose temperature is 0 °C is brought into thermal contact with body Y of equal mass and temperature 100 °C. The only exchanges of heat that take place are between X and Y. The specific heat capacity of X is greater than that of Y. Which statement about the final...
  17. A

    Two monatomic ideal gases are in thermal equilibrium with ea

    Homework Statement Two monatomic ideal gases are in thermal equilibrium with each other. Gas A is composed of molecules with mass m while gas B is composed of molecules with mass 4m. The ratio of the average translational kinetic energies KA/KB is: Homework Equations KE=0.5xmxVavarage^2...
  18. luckyMee

    What are the thermal properties of ice cream?

    What are the thermal properties of ice cream? any helpful journals or pdfs for this kind of study? thank you ☺
  19. A

    Thermometer/ reproducible thermal phenomena

    What are reproducible thermal phenomena that are used to calibrate thermometers?
  20. Vitani11

    Temperature Calculation for a Distant Star with Thermal Excitation

    Homework Statement The spectrum of a distant star shows that one in 3x106 of the atoms of a particular element in its first excited state 7.3 eV above the ground state. What is the temperature of the star? (You can ignore the other excited states and assume the ratio of statistical weights is...
  21. Eclair_de_XII

    Finding coefficient of kinetic friction from thermal energy?

    Homework Statement "A rope is used to pull a ##\frac{357}{100}kg## block at constant speed ##\frac{203}{50}m## across a horizontal floor. The force on the block from the rope is ##\frac{768}{100}N## and directed ##15°## above the horizontal. What are (a) the work done by the rope's force, (b)...
  22. B

    Solidworks thermal simulation: is this logical?

    I just ran 2 simulations on Solidworks, same assembly, same initial conditions on all pieces, pretty much I "Cloned" the thermal study and just changed one piece So, from the assembly above you can see the materials for most pieces, the 2 grey pieces in the center are 2 aluminum plates with a...
  23. Conservation

    Total thermal energy from heat equation

    Homework Statement Homework Equations Heat equation The Attempt at a Solution I can derive E(t) to get integral of du/dt over 0 to L, which is the same as integrating the right hand side of the original equation (d2u/dx2+sin(5t); while this allows me to take care of the d2u/dx2, I don't know...
  24. Carlos de Meo

    Thermal radiation, emissivity and Kirchhoff

    Hi Guys Studying thermal radiation here and I am kinda stuck at one point Kirchhoff law states that at thermodynamical equilibrium, the amount of energy absorbed must be reemited. But before the system reaches equilibrium, is there a model to predict how much energy of these photons absorbed...
  25. A. Neumaier

    I Entangled particles in the thermal interpretation

    Ah. It was skepticism about publishing, not about giving a comprehensive account! Yes, I am preparing a book on quantum mechanics, which will contain an account of the thermal interpretation - but primarily to macroscopic, nonrelativistic reality, where it is obvious that it gives the correct...
  26. D

    I Thermal expansion in harmonic potential

    It is generally said that thermal expansion is a process determinated by the anharmonic terms in the potential of a crystalline solid. However, in the Course of Theoretical Physics by Landau Lifshitz, Statistical Physics part 1, paragraph 67, a form for the coefficient of thermal expansion is...
  27. cehen

    ANSYS transient thermal boundary conditions

    Hi all. I don't have as much experience with thermal analyses in ANSYS, and I can't quite figure out a problem that I'm working on. I'm trying to find the temperature distribution in a box that has a circle in the center. I want to define constant temperature b.c.'s at the walls and the circle...
  28. Carlos de Meo

    Thermal conductivity of SiC and the mechanisms

    Hi Guys I was studying the thermal properties of SiC at high temperatures and now i have a few questions Usually, at high temperatures, the photons effect are much more intense than phonons at high temperature, correct? According to Rosseland heat diffusion equation Krad = 16σT3 /3β, β= 4πK/λ, σ...
  29. H

    Comparing thermal emission of 2 devices must be at same V?

    When i compare the thermal emission of two devices, should i apply same voltage (both draw different currents) or should I make sure the power is the same for both?
  30. M

    Help with project design, thermal properties

    I'm trying to make a pizza oven, but rather than brick or refractory, steel. I want to use a hemisphere and have it fed by pellets. I've been told by people on wood oven forums that I won't get the heat needed. I'm wanting 900 F at the hearth of the oven, using pellets for heat (roughly 8000...
  31. ramzerimar

    Engineering Mechatronics or Thermal and Fluids for specialization?

    I'm a Mechanical Engineering student at the 4th semester, and I've been thinking about what specializations I should pursue after I get my bachelor's degree. I've always find mechatronics (control and automation) to be quite fun. I've developed some projects using Arduino and studied a little...
  32. D

    What is the significance of thermal expansion coefficients in material research?

    Hi all, I am very new to physics and have little to no background in engineering, however I am a biochemistry major whoe somehow wound up in material research lab. One thing I am having trouble understanding the thermal expansion coefficients, how they relate to each other and which one I...
  33. S

    Thermal expansion of liquid in a tube

    Homework Statement A cylindrical glass tube (linear thermal expansion coefficient ##\alpha##) contains liquid (volume thermal expansion coefficient ##\beta##). The height of the tube is ##h_{t,0}## and the height of the liquid inside of it is ##h_{l,0}##. If the temperature changes of an amount...
  34. S

    Reversible heat exchange between water and ice

    Homework Statement In an adiabatic container are placed , in rapid succession , a mass of ice , ##m_I= 2 kg## , at temperature ##T_I = -10 ◦C## and a mass of water , ##m_W = 1 kg## , at the temperature ##T_W = + 20 ◦C## . Determine : a) the total mass of water present in the container at...
  35. S

    Thermal Radiation of a steel ball

    Why does a steel ball appear hotter than a charcoal piece at the same temperature when picked up by bare hands?
  36. O

    Why isn't rubber a better thermal insulator than styrofoam?

    I haven't studied materials in depth, but I would assume that something like rubber would make a good insulator because of its bounciness. The molecules of a substance contained in a rubber container would collide with the walls of the container in a very elastic collision, and the kinetic...
  37. S

    Calculating the output temperature of a Solar Thermal system

    So say I have a PV-Thermal array and assuming standard test conditions. How would I calculate the temperature of the water coming out of the system? The thermal output of the system is 67.5kWp with a maximum flow rate of 65L/h. Approximately 500m of 3/4" pipes.
  38. T

    Thermal Equilibrium of Hot Iron & Water

    Homework Statement A hot (800 K) iron nail of mass 150 g is placed into a 1.0 kg of water at 25°C. What is the common temperature of the 2 objects once they have reached thermal equilibrium? Assume no change of state of the water. Heat capacity of iron nail is 450 J/kg/K Heat capacity of...
  39. S

    Limiting factors of PV Modules and Thermal Collectors

    What limits the efficiency of a PV Module and a Thermal Collector? PV efficiecy is limited more by temperature in summer than by illumination in winter. Thermal Collector efficiency is limited by temperature and illumination in winter. The lower the temperature a thermal collector will be...
  40. Erenjaeger

    Calculating Thermal Expansion: Glass Rod Length, Diameter, and Volume Increase

    A) The active element of a laser is made of a glass rod 25.0 cm long and 1.40 cm in diameter. Assume the average coefficient of linear expansion of the glass is equal to9.00 10-6 (°C)−1. The temperature of the rod increases by 64.0°C. i) What is the increase in length? I worked this out to be...
  41. S

    Efficiency of a PV module and solar thermal collector

    Does the efficiency of a PV module and solar thermal collector go down as ambient temperature (outside temperature) increases? I know there are other factors that influence efficiency, but I'm only considering the one parameter of temperature on a PV module and solar thermal collector.
  42. naima

    A Is the vacuum a thermal state?

    Please look at the wikipedia article about thermal coherent states. We can only consider the states centered at the origin (##\alpha## = 0). If i understand what is written the vacuum is a pecular thermal state in the limit of a null temperature. I can understand that no energy can be borrowed...
  43. naima

    I Quantum jitter vs thermal jitter

    In this book Susskind writes that if thermal jitter can burn our nerves, quantum jitter cannot. He explains why: "Even though quantum jitters can be incredibly energetic, they cause no pain. Why? there is no way to borrow energy from the ground state. And quantum jitter is what is left over when...
  44. happytolearn

    Transient thermal analysis in ANSYS

    I want to do a transient thermal analysis in butt welded joint.The heat flow I have given 3200 watt(Q = efficiency x current x voltage = 0.8 x 160 amp x 25 volt)to the welding zone, given 20 load step(as welding is completed in 20 sec),convection co-efficient = 11.14, emissivity = .4 and applied...
  45. S

    Thermal Conductivity and Lasers

    Homework Statement My textbook on lasers has mentioned thermal conductivity a few times, but hasn't specifically mentioned it's importance. I'm at a part talking about Nd:Glass lasers and it says that glass has a lower thermal conductivity than Nd:YAG lasers, which prohibits continuous wave...
  46. Paul Colby

    A Why are low pressure gas discharge lamps thermal sources?

    When an atom makes a single photon transition it adds a single photon to the radiation field. One might then expect that a low pressure gas discharge would emit photons in Fock states? How is it that photon of an atomic spectral line produced in a low pressure gas discharge become thermalized?
  47. RJLiberator

    Thermal Equilibrium Temperature Question Sodium and Water

    Homework Statement Expose the error: When sodium is placed in water, a violent reaction always occurs; therefore sodium and water can never be at the same temperature. Homework Equations Thermal equilibrium and temperature. Zeroth law. Isotherms. The Attempt at a Solution My Answer: The...
  48. S

    Thermal Resistance of Heat Sink

    Homework Statement Calculate the thermal resistance of the heat sink required for the regulator of the question above given the information below [from the datasheet] and the data in the table. Max Load Current (Ilm)= 1A Max Ambient Temp (Ta)= 75°C Thermal Resistance Case to Heat (θchs)=...
  49. Idrees Afridi

    Temperature gradient vs thermal boundary layer thickness

    what does the relation between the temperature gradient inside the thermal boundary and thermal boundary layer thickness i mean what will be the temperature gradient ( high or low) when the thermal boundary layer is thick relative to the thin one? Kindly explain mathematically and physically as...
  50. E

    I Pn junction to reach thermal equilibrium

    Hello! Some of the processes caused by a pn junction are not clear for me. Just after the contact between the p and the n region, a migration of charges happens in a semiconductor junction in order to reach an equilibrium condition. A valence band and a conduction band are present in both...
Back
Top