Quick Answer: Stefan Boltzmans Apparatus determines the Stefan Boltzmann constant from the temperature rise of a 20 mm copper test disc placed at the centre of a 200 mm dia. copper hemisphere, which sits in a 250 mm dia. hot water jacket. A buzzer timer sounds every 5 seconds for readings.
Last updated: October 2026
Key Features
Copper hemisphere, 200 mm dia., in a 250 mm dia. water jacket
Copper test disc, 20 mm dia., with thermocouple at the centre
Water heating tank with electric immersion heater
Multichannel digital temperature indicator, 0 – 200 °C, 0.1 °C least count
Audible buzzer with timer every 5 seconds
Technical manual supplied
Technical Specifications
Specification
Value
Hemisphere
Copper sheet, 200 mm dia.
Water jacket
250 mm dia.
Test disc
Copper, 20 mm dia., thermocouple at centre
Water heating
Tank with electric immersion heater
Temperature indicator
Multichannel digital, 0 – 200 °C, 0.1 °C least count
Timer
Audible buzzer, every 5 seconds
Supply
230 V, 15 A, AC with earthing connection
About This Product
Hot water from the heating tank surrounds the hemisphere, and when the blackened disc is inserted at its centre it gains heat from the hemisphere by radiation. The rising disc temperature, read at 5-second intervals, gives the rate from which the Stefan Boltzmann constant is calculated. This HEAT TRANSFER LAB apparatus is built to determine that constant, which is important in heat transfer.
Frequently Asked Questions
Q1. How is the Stefan Boltzmann constant determined? The blackened disc is inserted at the centre of the hot hemisphere and heated by radiation. Its temperature rise, measured at 5-second intervals, gives the rate from which the constant is determined.
Q2. What is the range of the temperature indicator? 0 – 200 °C with a least count of 0.1 °C.
