OCR · A-Level · Physics
Course version: H556 · Version from Sept 2015
(b) absolute scale of temperature (i.e. the thermodynamic scale) that does…
Full specification wording
Temperature: (b) absolute scale of temperature (i.e. the thermodynamic scale) that does not depend on property of any particular substance
The absolute scale of temperature, also called the thermodynamic scale, is defined independently of any particular substance.
Checked against the OCR H556 specification (opens in a new tab) on .
- Point 2 of 4
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The absolute scale of temperature, also called the thermodynamic scale, is defined independently of any particular substance. It is based on fundamental thermodynamic principles, such as the efficiency of a Carnot engine, rather than on the expansion of a specific material like mercury or alcohol. The kelvin (K) is the unit of this scale, with 0 K being absolute zero, the temperature at which particles have minimum possible kinetic energy. Because the scale does not rely on a material property, it provides a universal and consistent way to measure temperature.
For example: The triple point of water is defined as 273.16 K, and other temperatures are realised using primary thermometers that operate on fundamental principles.
What earns the marks
- The absolute scale of temperature is independent of the properties of any particular substance.
- The kelvin (K) is the unit of the absolute scale, with 0 K defined as absolute zero.
- The triple point of water is a fixed point on the scale, defined as 273.16 K.
Common mistakes and how to put them right
Misunderstanding: the thermodynamic scale depends on the expansion of mercury.
Put it right: It is independent of any material property; empirical scales depend on such properties.
Misunderstanding: absolute zero is the freezing point of water.
Put it right: Absolute zero is 0 K, the temperature at which particles have minimum kinetic energy, not the freezing point of water.
Misunderstanding: the thermodynamic scale is the same as the Celsius scale.
Put it right: The Celsius scale is defined using the ice and steam points of water, while the thermodynamic scale is defined independently of any substance.
Exam tips
- Remember that 'absolute scale' and 'thermodynamic scale' are the same thing.
- Focus on the key phrase 'does not depend on property of any particular substance' when evaluating options.
- Recall that the kelvin is the SI unit of temperature and that 0 K is absolute zero.
Try the lesson
The start of the Temperature: (b) absolute scale of temperature (i.e. the thermodynamic scale) that does not depend on property of any particular substance lesson, made from checked teaching notes for this specification point.
Listen
The absolute scale of temperature, also called the thermodynamic scale, is defined independently of any particular substance. It is based on fundamental thermodynamic principles, such as the efficiency of a Carnot engine, rather than on the expansion of a specific material like mercury or alcohol. The kelvin (K) is the unit of this scale, with 0 K being absolute zero, the temperature at which particles have minimum possible kinetic energy. Because the scale does not rely on a material property, it provides a universal and consistent way to measure temperature. For example, the triple point of water is defined as 273.16 K, and other temperatures are realised using primary thermometers that operate on fundamental principles. A strong answer earns marks for these points. The absolute scale of temperature is independent of the properties of any particular substance. The kelvin (K) is the unit of the absolute scale, with 0 K defined as absolute zero. The triple point of water is a fixed point on the scale, defined as 273.16 K. A common slip: Misunderstanding: the thermodynamic scale depends on the expansion of mercury. Instead, it is independent of any material property; empirical scales depend on such properties. Exam tip: Remember that 'absolute scale' and 'thermodynamic scale' are the same thing.
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Key words
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Absolute scale of temperature
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Fundamental thermodynamic principles
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Kelvin
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Triple point of water
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See every definition
- Absolute scale of temperature
- Also called the thermodynamic scale, it does not depend on property of any particular substance.
- Fundamental thermodynamic principles
- The basis of the scale, such as the efficiency of a Carnot engine, rather than the expansion of a specific material.
- Kelvin
- The unit of the absolute scale, with 0 K being absolute zero, the temperature at which particles have minimum possible kinetic energy.
- Triple point of water
- A fixed point on the scale, defined as 273.16 K.
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