Breckland Scientific 2023 Catalogue

Heat & Energy

Thermal Convection

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3 BALL & RING A simple and economical device for demonstrating the thermal expansion of solids. Comprises an annular brass ring and ball both mounted on insulated handles. When cold the ball easily passes through the ring, but after heating it will not. If both are heated equally, then the ball also passes through the ring. Cat No. Description Price Per HTM-050-100 Ball & Ring 10.16 ea. 4 BIMETALLIC COMPOUND BAR To show the unequal or differential expansion of two different metals in bimetallic strips. Comprising two strips, each of different metal (Brass & Steel) of same size, riveted together end to end and fitted on an insulated handle. On heating, the compound strip bends with the metal having the greater coefficient of expansion on the concave side and other one on convex side. Returns back to its original shape on cooling. Strip is 150x20mm mounted in a wooden handle. The strip is only 1.5mm thick so that very little heat is required to produce considerable bending. Length overall 270mm. Cat No. Description Price Per HTM-200-100 Bimetallic Compound Bar 7.91 ea. The tube should be filled with water and the apparatus carefully mounted using a retort stand with clamp on either side. A few crystals of potassium permanganate (or some drops of concentrated coloured dye/ink) can then be introduced into the open top of the tube, whilst one of the bottom corners is heated gently with a low Bunsen flame. As heat rises up this side of the tube, colour from the crystals or dye will begin to move along the top and then down the opposite side, due to the convection currents generated. Finally, the coloured water will move along the bottom of the apparatus and back up the side above the heated corner. Dimensions: 380 x 300 mm approx. Cat No. Description Price Per HPL-100-100 Convection in Water Apparatus 25.28 ea. 1 CONVECTION IN AIR APPARATUS Also known as the mine shaft apparatus, as it uses the same principal which was historically used to ventilate metal mines. A candle represents the furnace which was used at the time (early 19th century) to heat air at the bottom of one of the mine shafts, causing stale air it to rise up to the surface, resulting in fresh air being drawn down another shaft and into the mine, to ventilate it. The apparatus consists of a metal box with a sliding glass plate at the front, with two glass chimneys mounted above holes in the top of the box (the ‘mine shafts’). A small candle or tea light is then placed below one of the chimneys and lit. The heat from the flame causes warm air to rise up the chimney, due to the convection currents created, resulting in cooler air then being drawn down the other chimney to replace it. In order to visualise the movement of air, a smoke match or smouldering piece of cardboard or string can be held close to the opening of the chimney which does not have the candle underneath; the smoke can be seen being drawn down into the box and back out through the other chimney. Dimensions: 220 x 100 x 165 mm approx. Cat No. Description Price Per HPG-400-100 Convection in Air Apparatus 28.66 ea. HPG-400-150 Spare Chimneys 9.23 pr BRN-400-100 Smoke Matches 2.98 25pk 2 CONVECTION IN WATER APPARATUS This apparatus comprises a rectangle formed from 20mm diameter borosilicate glass tubing, for demonstrating thermal convection in water.

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Convection in Air Apparatus

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Convection in Water Apparatus

Thermal Expansion

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Ball & Ring

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Bimetalic Compound Bar

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