General Purpose Glass Thermometers, 305 mm, Spirit Filled, Yellow Back

Description

The General Purpose Glass Thermometers, 305 mm, Spirit Filled, also known as laboratory spirit thermometers, liquid-in-glass thermometers or partial immersion thermometers, are designed for measuring temperatures during routine laboratory experiments, scientific testing and educational activities. Manufactured by Brannan, these thermometers use a traditional liquid-in-glass measuring system with red spirit filling and clearly graduated Celsius scales. Their non-mercury construction provides a practical option for general temperature monitoring without requiring batteries or electrical power.

The range includes two temperature options: -20°C to +110°C and -20°C to +150°C, both featuring 1.0°C scale divisions. These variations allow laboratory users to select a thermometer according to the expected temperature range of their experiments. The -20°C to +110°C variation is suitable for routine heating and cooling investigations, water temperature measurements and general science experiments. Its yellow-backed scale provides a contrasting background for reading the red liquid column. The -20°C to +150°C variation offers an extended upper temperature range for suitable laboratory applications. It uses the same liquid-in-glass measurement principle, with a graduated Celsius scale designed for direct temperature readings.

Both thermometers measure 305 mm in length and 6.5 mm in diameter, providing a slim glass construction suitable for compatible laboratory containers. Their elongated stems allow the graduated scale to remain visible during measurements. The red spirit filling responds to temperature changes through thermal expansion and contraction. As the liquid moves within the narrow capillary tube, its position against the printed graduations indicates the measured temperature. The yellow-backed glass helps distinguish the red liquid column from the scale markings, making readings easier to observe during classroom demonstrations and routine laboratory procedures.

These instruments feature a 76 mm partial immersion design. For measurements consistent with their specified accuracy, users should immerse each thermometer to its designated immersion depth rather than submerging the entire glass stem. The manufacturer’s stated accuracy is ±1.0°C at 35°C for the -20°C to +110°C model and ±1.5°C at 35°C for the corresponding yellow-backed -20°C to +150°C model. These accuracy values are separate from the 1.0°C graduation intervals. A non-roll end cap helps prevent the thermometer from rolling across laboratory benches. The integrated suspension ring also provides a convenient way to store the instrument in a suitable holder when it is not in use.

For reliable measurements, immerse the sensing bulb to the specified depth, allow the liquid column to stabilise and read the scale at eye level. Avoid contact with container surfaces that may influence the measurement. Safety Precautions: Handle glass thermometers carefully to prevent breakage. Avoid sudden temperature changes, direct flame contact and exposure beyond the specified measuring range. If broken, follow laboratory procedures for handling glass fragments and spilled filling liquid. Each selected variation is supplied as one Brannan Spirit Filled Glass Thermometer in an individual protective tube. Calibration certificates are available separately on request.

LabChoice Australia supplies laboratory glass thermometers and temperature measurement equipment for secondary schools, universities, research facilities and science teaching laboratories across Australia.