Related Experiment Video
Updated: Jul 15, 2026
08:13
Differential Scanning Calorimetry — A Method for Assessing the Thermal Stability and Conformation of Protein Antigen
Published on: March 4, 2017
Low-temperature differential-thermal analysis to measure variations in entropy
1Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland. schilling@physik.uzh.ch
The Review of Scientific Instruments
|April 7, 2007
Summary
Researchers precisely measured entropy changes in small solid samples using differential-thermal analysis. This technique accurately detects phase transitions without instrumental broadening, even in milligram-sized samples.
Area of Science:
- Thermodynamics
- Materials Science
- Solid-State Physics
Background:
- Entropy (S) is a fundamental thermodynamic property.
- Measuring entropy changes in small solid samples at low temperatures presents challenges.
- Accurate measurement of entropy is crucial for understanding material behavior and phase transitions.
Purpose of the Study:
- To develop and present a precise method for measuring entropy variations in small solid samples.
- To demonstrate the application of this method for temperature (T) and magnetic field (H) dependencies.
- To highlight the suitability of the technique for detecting sharp phase transitions.
Main Methods:
- Utilized a differential-thermal analysis technique.
- Applied the method to small solid samples below room temperature.
- Measured entropy variations as a function of temperature and external magnetic field.
Main Results:
- Achieved precise measurements of entropy variations.
- Demonstrated that the differential-thermal analysis technique minimizes instrumental broadening.
- Successfully detected sharp phase transitions in milligram-sized samples.
Conclusions:
- The described differential-thermal analysis technique offers a precise and effective way to measure entropy variations in small solid samples.
- This method is particularly advantageous for identifying sharp phase transitions with high fidelity.
- The technique is well-suited for low-temperature thermodynamic studies of condensed matter.
Related Concept Videos
01:18Entropy
The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
02:39Entropy
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...
01:26Entropy and the Second Law of Thermodynamics
Consider an isolated system in which a hot object is placed in contact with a cold one. This is an irreversible process that eventually leads both objects to reach the same equilibrium temperature. It is crucial to note that the constituents of any substance exhibit increased disorder at higher temperatures. As a cold substance absorbs heat, its constituents become more disordered. The energy transfer from a hotter object to a cooler one increases the system's disorder or randomness. This...
01:20Entropy and the Second Law of Thermodynamics
The second law of thermodynamics can be stated quantitatively using the concept of entropy. Entropy is the measure of disorder of the system.
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
01:21Entropy Changes Accompanying Specific Processes
Entropy, a measure of disorder in a system, changes during phase transitions like freezing or boiling. At the transition temperature Ttrs, where two phases are in equilibrium, the phase transition is a reversible process. The entropy change can be calculated from a substance's enthalpy of transition using the equation ΔStrs = ΔtrsH /Ttrs.When a perfect gas expands isothermally from one volume to another, entropy increases logarithmically with volume. Conversely, isothermal compression results...
01:14The Entropy as a State Function
Consider an arbitrary process that moves between two specific states (A and B) in a cyclic manner. This process is reversible and broken down into smaller parts that each follow a Carnot cycle. A Carnot cycle has two isothermal (constant temperature) processes. During these processes, the ratio of the amount of heat transferred to their respective temperature remains constant. The other two processes in the Carnot cycle are also reversible but adiabatic, which means they occur without any heat...