Breckland Scientific 2021 Catalogue

Gas

Gas Laws

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1 CHARLES LAW APPARATUS Used to demonstrate the thermal expansion of gases, to verify Charles law and to estimate a Celsius value for the absolute zero of temperature. Apparatus provided: 1 glass Charles law tube with bung and 2 clips, 1 glass beaker with stirrer. Cat No. Description Price Per HPG-250-100 Charles Law Apparatus 40.65 ea. 2 CHARLES’ LAW MOUNTED Comprises a capillary tube, which is sealed at the bottom, having a graduated scale from 0 to 200mm. This is mounted onto a plastic former which also has a -10 – 100°C thermometer mounted alongside the tube. The tube is 245mm long and includes a small bead of coloured oil which has already been injected into the tube at about the 50mm mark. The overall length is 350mm, including a back plate with a hole at the top to fix to a retort stand to allow the apparatus to be suspended in a tall beaker of water (not supplied). By heating the water and taking a temperature and scale reading every 30 seconds, a graph of the results can be plotted. Through a line of best fit and extrapolation absolute zero can be demonstrated. The straight line supports Charles’ Law demonstrating that volume of a gas is directly proportional to its temperature provided the pressure is kept constant. (In this case the pressure is atmospheric pressure). The Kelvin scale may then be introduced. Available individually or as a class set of 10 in a Gratnells tray. Cat No. Description Price Per HPG-265-100 Charles’ Law Mounted 17.90 ea. HPG-265-110 Charles’ Law Mounted Class Set - NEW! 169.90 10 3 CHARLES’ LAW GRADUATED TUBE - NEW! This simple Charles’ law tube consists of an unmounted, uniform capillary tube, which is sealed at one end and has a linear scale along its length, marked in cm and mm. Although traditionally used with a bead of mercury, a bead of concentrated sulphuric acid or coloured oil can be used instead, by inserting about half way down the tube, which can then be heated in a water bath to investigate temperature/volume for the enclosed air column. To place a bead of liquid into the capillary it is best to ensure the tube is thoroughly dried in an oven first, at high temperature for an hour or two. After removing from the heat, if the tube is then immediately placed with the open end in some coloured oil or sulphuric acid, a bead of liquid should be drawn into the tube as it cools down. Readings are taken directly from the scale on the tube. Comes supplied in a protective plastic case, with instructions. Cat No. Description Price Per HPG-275-100 Charles’ Law Graduated Tube 6.69 ea. 4 MAGDEBURG HEMISPHERES - STANDARD Consists of two plastic hemispheres about 100mm in diameter, both having handles. One has a plastic stopcock for pumping out air and releasing vacuum and a rubber O-ring seal inside. Can be connected to any suitable vacuum pump for evacuation. - see page 376. Cat No. Description Price Per HPG-600-100 Standard Magdeburg Hemispheres 33.99 ea. 5 MINI MAGDEBURG HEMISPHERES These mini-Magdeburg hemispheres demonstrate the force of air pressure without the need for a vacuum pump. In this modern variant of a famous 17th-century experiment, students place the faces of two hemisphere cups together and squeeze them, forcing out the air between them. Pulling the cups apart is then surprisingly difficult due to the lack of air pressure between them. Each of the 7.5 cm diameter rubber hemisphere has a 2-finger tug handle and 2 release knobs. Cat No. Description Price Per HPG-580-100 Mini Magdeburg Hemispheres 9.01 2

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Charles Law Apparatus

Mounted Charles Law

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Charles Law Graduated Tube

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Standard Magdeburg Hemispheres

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Mini Magdeburg Hemispheres

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