Experiments for the determination of the coefficient of linear expansion
First, the purpose of the experiment.
1.Understand the principle of thermal expansion of an object and the concept of linear expansion coefficient;
2.Master the method of determining the coefficient of linear expansion through experiments;
3.Develop experimental operation skills and data processing ability.
Second, the principle of experiment.
The coefficient of linear expansion is the relative degree to which the length of an object increases or decreases when the temperature increases or decreases, and is measured in units of 1. According to the principle of thermal expansion, when the temperature of an object changes, its length changes, and the amount of change is proportional to the amount of temperature change. In this experiment, the linear expansion coefficient is calculated by measuring the change in length of the specimen when the temperature increases or decreases.
3. Experimental procedures.
1.Prepare experimental equipment: thermodilatometer, thermometer, thermostatic water tank, balance, ruler, sample, etc.;
2.Place the specimen on the measuring section of the thermodilatometer to ensure that the specimen is in close contact with the measuring section;
3.Adjust the thermostatic sink to a set starting temperature, such as 20;
4.Turn on the thermostatic sink to make the water in the sink heat up slowly, and observe the changes in the thermometer;
5.When the thermometer shows that the temperature reaches the set value (e.g., 40), the heating is stopped immediately, and the length of the specimen on the thermodilatometer is recorded at this time;
6.Measure the temperature of the water in the thermostatic sink with a ruler to the accuracy of 01℃；
7.Record the experimental data in the data**;
8.According to the above steps, the experiments were carried out at different temperature points and the data were recorded.
9.Based on the experimental data, the coefficient of linear expansion is calculated.
4. Data analysis and processing.
1.According to the experimental data, the length change of the sample at each temperature point was calculated.
2.The temperature change and length change were plotted into curves to observe their change rules.
3.The linear expansion coefficient was obtained by using the method of curve fitting or linear regression.
4.The error analysis of the obtained linear expansion coefficient was carried out to evaluate the reliability of the experimental results.
5. Experimental conclusions.
Through this experiment, we have mastered the method of measuring the linear expansion coefficient and obtained the linear expansion coefficient of the sample. The experimental results show that the length of the specimen gradually increases with the increase of temperature, and the magnitude of the linear expansion coefficient reflects the degree of thermal expansion of the object. This experiment is of great significance for an in-depth understanding of the principle and practical application of thermal expansion of objects.