### Heat

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## LETI-12 Apparatus of Measuring Specific Heat Capacity of Metal

Features

• High performance

• Simple structure, stable and reliable

• Affordable

Introduction

The heat required for a substance of unit mass to rise temperature 1 K (1 °C) is called the specific heat capacity of the substance, and its value varies with temperature. According to Newton's cooling law, cooling method is one of the common methods for measuring the specific heat capacity of metals. If the specific heat capacity at different temperatures of a standard specimen is known, the specific heat capacity at different temperatures of various metals can be measured by using the cooling curve.

The LETI-12, Apparatus of Measuring Specific Heat Capacity, is designed with a few innovations compared with the traditional experimental methods and experimental instruments. In the aspect of experimental method, the cooling conditions of the specimen are no longer only natural cooling in room temperature environment, but also use a fan to create forced convection for cooling environment. The advantages and disadvantages of the two cooling conditions can be compared and analyzed. In the aspect of experimental device, the heating device is a PTC heating plate working at a safe voltage with temperature limiting. A temperature sensor of PT100 resistance is used to replace the traditional Copper-constantan thermocouple that needs an icy reference end to work. The specimen chamber is changed from the traditional up and down vertical structure to the left and right horizontal structure. The heater movement in the specimen chamber is also changed from up and down to left and right, making the experimental operation more convenient.

This apparatus takes copper as the standard specimen and measures the specific heat capacity of iron and aluminum specimens at 100 °C under two different cooling environments, i.e. forced convective cooling and natural cooling, enables students to understand the relationship between the cooling rate of metal and the cooling environment, and master the experimental method of measuring specific heat capacity of metal by cooling.

This experimental apparatus mainly consists of a main electric unit, a heater, a specimen chamber, a cooling fan, a PT100 platinum resistance, and so on. Using this apparatus, the following experiments can be performed:

1. Learn to measure temperature using PT100 platinum resistance;

2. Under forced convective cooling, measure specific heat capacity of iron and aluminum specimens at 100 °C;

3. Under natural cooling, measure specific heat capacity of iron and aluminum specimens at 100 °C.

Key Specifications

 Description Specifications PTC heater working voltage 30 VACstable temperature > 200 °Ctemperature limiting 260 °C Digital Ohm meter 0 ~ 199.99 Ω, resolution 0.01 Ω Metal specimens copper, iron and aluminum, each one, length 65 mm, diameter 8 mm

Part List

 Description Qty Electric unit 1 Specimen chamber 1 (including heater, fan, PT100) Specimen 3 (copper, iron, aluminum) Connection wires 2 Stop watch 1 Power cord 1 Instruction manual 1

An example of experimental results