Words for the Words for the Summer Heat Remember to stay hydrated. Style: MLA. English Language Learners Definition of temperature. Kids Definition of temperature. Medical Definition of temperature. Get Word of the Day daily email! Test Your Vocabulary. Can you spell these 10 commonly misspelled words? Love words? Need even more definitions? Just between us: it's complicated. Ask the Editors 'Everyday' vs. What Is 'Semantic Bleaching'? Thermal equilibrium is not a purely energy phenomena.
Energy is conserved when two objects reach thermal equilibrium, but it would also be satisfied if one object got hot and the other one became cold. Thermal equilibrium is a statistical process. It just so happens that the most probable outcome for two objects in contact is that they reach the same temperature. The other weird cases one getting hot and one getting cold can also technically happen, but their chances are way less than you winning the lottery and your chance of winning the lottery is essentially zero.
Since temperature is really a statistical quantity, you can't have a temperature of a single particle. So, the next time someone talks about the temperature of a single electron—or worse, the temperature of a photon—maybe you should just walk away.
There are quite a few temperature scales, but these are three most common: Celsius, Fahrenheit which I can never spell correctly , and Kelvin. I know that most of the civilized world uses Celsius, but I just have trouble training my brain to think of temperature in this scale. I'm probably too old to change. Also, I always think of this graphic display of the temperature scales which says that 0 degrees Celsius is cold, but at a temperature of degrees Celsius you would be dead the temperature of boiling water.
How do you calibrate a temperature scale? The Celsius scale is easy. The zero value is at the freezing point of water and the value is at the boiling point.
That's fairly easy to reproduce but these values do depend on atmospheric conditions, so it's not a perfect method to calibrate a thermometer. The Kelvin scale is just like the Celsius scale, but it is shifted by With the Kelvin scale, you don't get negative temperatures—so that's useful in lots of calculations.
But what about the Fahrenheit scale? Actually, this is something that's interesting. If you mix ice and salt and a little water , the coldest you can get the mixture is zero. That is surprisingly cold and why you use salt-ice mixture to make homemade ice cream. Oh well, I guess we won't know until someone invents a time machine. Anyway, when the MythBusters tested the thermal properties of a tauntaun they used a temperature of —so there. Now for some math. Since both of these are linear temperature scales, I can find a function for the Celsius temperature as a function of Fahrenheit temperature.
To do this, I need two data points to make a line. Good thing I already have them—they are the boiling and melting point of water. This temperature is called absolute zero. Today we know that most gases first liquefy and then freeze, and it is not actually possible to reach absolute zero.
The numerical value of absolute zero temperature is — Figure 7. Graph of pressure versus temperature for various gases kept at a constant volume. Note that all of the graphs extrapolate to zero pressure at the same temperature. Thermometers actually take their own temperature, not the temperature of the object they are measuring.
This raises the question of how we can be certain that a thermometer measures the temperature of the object with which it is in contact. It is based on the fact that any two systems placed in thermal contact meaning heat transfer can occur between them will reach the same temperature. That is, heat will flow from the hotter object to the cooler one until they have exactly the same temperature.
The objects are then in thermal equilibrium , and no further changes will occur. The systems interact and change because their temperatures differ, and the changes stop once their temperatures are the same. Thus, if enough time is allowed for this transfer of heat to run its course, the temperature a thermometer registers does represent the system with which it is in thermal equilibrium.
Thermal equilibrium is established when two bodies are in contact with each other and can freely exchange energy. Furthermore, experimentation has shown that if two systems, A and B, are in thermal equilibrium with each another, and B is in thermal equilibrium with a third system C, then A is also in thermal equilibrium with C.
This conclusion may seem obvious, because all three have the same temperature, but it is basic to thermodynamics. It is called the zeroth law of thermodynamics. If two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C. This law was postulated in the s, after the first and second laws of thermodynamics had been developed and named.
It is called the zeroth law because it comes logically before the first and second laws discussed in Thermodynamics. An example of this law in action is seen in babies in incubators: babies in incubators normally have very few clothes on, so to an observer they look as if they may not be warm enough. However, the temperature of the air, the cot, and the baby is the same, because they are in thermal equilibrium, which is accomplished by maintaining air temperature to keep the baby comfortable.
No, the system can be divided into smaller parts each of which is at the same temperature. We say that the temperature is an intensive quantity. Intensive quantities are independent of size. Kelvin scale: temperature scale in which 0 K is the lowest possible temperature, representing absolute zero. Skip to main content. Temperature, Kinetic Theory, and the Gas Laws. Search for:. Temperature Learning Objectives By the end of this section, you will be able to: Define temperature. Convert temperatures between the Celsius, Fahrenheit, and Kelvin scales.
Define thermal equilibrium. State the zeroth law of thermodynamics. Misconception Alert: Human Perception vs. Reality On a cold winter morning, the wood on a porch feels warmer than the metal of your bike. Example 1. What is it in K? Strategy To answer these questions, all we need to do is choose the correct conversion equations and plug in the known values.
Solution for Part 1 Choose the right equation. Example 2. Converting between Temperature Scales: the Reaumur Scale The Reaumur scale is a temperature scale that was used widely in Europe in the eighteenth and nineteenth centuries. Strategy To answer this question, we must compare the Reaumur scale to the Celsius scale. Making Connections: Absolute Zero What is absolute zero? The Zeroth Law of Thermodynamics If two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C.
Check Your Understanding Does the temperature of a body depend on its size? Solution No, the system can be divided into smaller parts each of which is at the same temperature. Conceptual Questions What does it mean to say that two systems are in thermal equilibrium?
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