Determination of the coefficient of expansion of a metal wire
First, the purpose of the experiment.
1.Master the definition and physical significance of the expansion coefficient of metal wire;
2.Learn and master the method of determining the expansion coefficient of metal wire;
3.Understand the differences in linear expansion coefficients of different metal materials and their influencing factors.
Second, the principle of experiment.
The coefficient of linear expansion is a relative amount that describes the increase in length of a metallic material at an increasing temperature. The mathematical expression is: = δl l * t, where is the coefficient of linear expansion, δl is the increase in length after the temperature increases, l is the original length, and δt is the increase in temperature. By measuring the length change of a metal material at different temperatures, its coefficient of linear expansion can be calculated.
3. Experimental procedures.
1.Prepare experimental equipment: thermal expansion tester, constant temperature water tank, metal samples, vernier calipers, thermometers, etc.;
2.The metal sample is fixed in the heating section of the thermal expansion tester to ensure that the sample is in good contact with the instrument;
3.Heat the water in the thermostatic water tank to the preset starting temperature, and put the heating section of the thermal expansion tester into the thermostatic water tank to ensure that the instrument is in full contact with the water;
4.The initial temperature of the experiment t1 and the original length of the metal sample l1 were recorded.
5.Slowly increase the temperature of the tank, and record the temperature t after each temperature increase and the corresponding length of the metal sample l;
6.Repeat step 5 until the temperature rises to the preset end temperature;
7.At the end of the experiment, the data is collated and the coefficient of linear expansion of the metal sample is calculated.
4. Data analysis and processing.
1.According to the experimental data, the relationship between temperature and length change was plotted.
2.The coefficient of linear expansion for each temperature point was calculated according to the diagram;
3.The linear expansion coefficient of all temperature points is averaged to obtain the final linear expansion coefficient value.
4.The differences of linear expansion coefficients and their influencing factors of different metal materials were analyzed.
5. Experimental conclusions.
Through this experiment, we have mastered the method of determining the expansion coefficient of metal wires, and understood the differences in linear expansion coefficients of different metal materials and their influencing factors. The experimental results show that the linear expansion coefficient of metal materials is related to its type, purity, crystal structure and other factors. In practical applications, the linear expansion coefficient of metal materials is of great significance for structural design and safe operation of thermal equipment. Through the measurement and study of the expansion coefficient of metal wire, it can provide theoretical basis and practical guidance for related fields. At the same time, this experimental method has high accuracy and reliability, and can be widely used in the determination of linear expansion coefficient of other materials.