Introduction

The phenomenon of expansion and contraction of objects due to temperature changes is called "thermal expansion". Its changing ability is the change in length caused by a unit temperature change under constant pressure (p is constant), which is the thermal expansion coefficient. The coefficient of expansion is the average elongation of a unit length of material in a certain temperature range for each degree of temperature increase. Generally speaking, solids expand the same in all directions. Therefore, the linear expansion law of a solid in one direction can be used to characterize its volume expansion.

This experimental device uses steam to heat copper tubes and aluminum tubes, and the displacement sensor directly measures the slight elongation or shrinkage of the experimental sample. The temperature sensor measures the temperature value of the sample tube, and finally realizes the measurement of the thermal expansion coefficient of metal. The entire experimental device consists of a steam generator, a metal sample tube, a sample tube holder, a temperature sensor and a micro displacement sensor. It uses a stable cooling process to dynamically measure the micro expansion and contraction of the sample during the cooling process, which is measured by two digital display meters. It can display the sample temperature and tiny displacement in real time, and can be expanded to use 2 voltage sensors to dynamically record the displacement and temperature change curves in real time.

Experiment Purpose

1. Learn to measure the thermal expansion coefficients of different metals.

2. Analyze various factors that affect measurement accuracy.

Features

• Transparent and intuitive experimental samples

  The design of the experimental sample tube is intuitive. You can directly see the temperature sensor and displacement sensor on the metal sample tube, which is very helpful for students to understand the measurement principle of the thermal expansion coefficient. Each metal sample tube is equipped with a transparent acrylic protective cover, which can not only visually observe the status of the sample, but also avoid the impact of changes in ambient temperature and airflow on the measurement results, and can also effectively avoid the risk of high temperature burns.

  
  

  
  

• Steam heating methord

  The use of a steam generator to heat the sample tube facilitates laboratory management, is simple and efficient.

  
  

  
  

• Digital displacement sensor

  A displacement sensor with a minimum measurement accuracy of 1um is used to ensure accurate measurement of the tiny elongation of the metal tube.

  
  

  
  

• High precision temperature sensor

  Using the national standard platinum resistance temperature sensor PT100, the temperature can be read directly, which improves the test accuracy and eliminates the errors caused by the low accuracy of the thermocouple.

  
  

  
  

• Various experimental samples

  Test samples: brass tube, aluminum tube, 304 stainless steel tube. Both are equipped with temperature sensors and acrylic protective covers.

  
  

  
  

• Can be expanded to digital experiments

  Digital experiment: The instrument can be equipped with 2-channel data acquisition interface and voltage sensor, and can be upgraded to a computer-based digital data acquisition and analysis experiment system.

Typical Data

Brass

Aluminum