Magdeburg Pressure Disks
The set consists of two plastic, 10cm-diameter hemispheres. Each half has a wooden handle firmly attached to it. One of the hemispheres has a raised edge to hold a rubber seal, while the other hemisphere has a stopcock for attaching to vacuum tubing. Join the hemispheres, hook them up to a vacuum pump, and evacuate the air inside the hemispheres. You will find it hard to pull them apart. Open the stopcock to let air in and the hemispheres will separate easily.
Linear Expansion Apparatus, Micrometer Screw Form
A 500 mm long metal rod is supported in a plated brass tube with three tubules for steam inlet, outlet and thermometer. The tube is mounted on a stand with an adjusting screw at one end and a micrometer screw reading to 0.01 mm on the other, with terminals for connecting a bell or galvanometer to indicate contact. With copper, brass and iron test rods but without thermometer.
Two cast metal uprights, height 18 cm, fitted with two nickel plated rods supporting expansion bar of length 38 cm. Expansion bar is fixed to one upright and moves a pointer on the other, when heated. With scale reading 0 to 90°, supplied with one each, aluminium, brass and iron expansion bars.
Fitted on a wooden base cast metal uprights and rod mountings. A 20-0-20 scale is provided to notice the expansion in rods. The counter weighted needle is used for easy reading. A knurling screw is provided for zero adjustment. Supplied with three metal rods one of each Aluminium, Brass and Steel.
A high quality apparatus to determine precisely co-efficient of expansion of various metals. An aluminium channel carries a 60 cm long metal rod enclosed in a heating jacket having three nipples for water intake, water outlet and thermometer insertion. Dial indicator is a precision instrument sensitive to 0.01 mm / division and is securely mounted. As the apparatus works with hot water, there is no danger from any steam escaping and causing burns on the skin. Complete with four expansion rods of steel, brass, copper and aluminium.