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School Spano |
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Function To show the thickening of the charges on the points. | |||
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Description On a glass column lies a sphere attached to the lower end of a metallic bar with a sharp end. The bar slides on a sleeve with set screws in order to bring the sphere to a short distance from another equal sphere fixed on the metallic basis. If we connect the two spheres with the conductors of an electrostatic machine, the charge cannot happen between the two spheres because the sharp end disperses it. | |||
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School Castelvė |
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Function To show the thickening of the charges on the points. | |||
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Description A metal bar is placed transversally on the top of a wooden support. A metallic star formed by six radius whose ends are curved is placed in its centre, where it can rotate. | |||
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School Spano |
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Function To show the thickening of the charges on the points. | |||
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Description To the same insulating support we can apply an accessory with a steel needle to hold a fly with five o six sharpened radius, or a brass pole at right angle that ends with a tip for the electric puff. A lateral hook allows connecting the apparatus to one of the conductors of the electrostatic machine that, in this case, must be used without capacitors. | |||
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School Azuni |
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Function To show the mechanical effect of the electric sparks. | |||
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Description Two brass columns are placed on a wooden basis. A glass with an iron needle in the middle is placed between the two columns. From the bar that joins the two columns comes down an iron needle that ends near the point of the needle placed in the glass. We can decide the distance between the points. It is possible to pierce a glass sheet placed between the two points by connecting them to a Leyden jar or an induction coil so as to obtain an electric discharge. | |||
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School Spano |
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Function To show the capability of an electric spark to pierce a glass sheet. | |||
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Description A metallic plate is fixed to a tripod. From the above end of a column of insulating material, fixed on one of its feet, comes a bar that ends with a ring. In the ring a metallic needle slides at friction. The needle is placed in correspondence to the centre of the plate. We place a glass sheet between the needle and the plate; we connect the ring to the armature of a capacitor of the electric machine and the base to the armature of another capacitor. We place the discharge conductors at 2 cm and we start the machine. With this disposition the discharge between the point and the plate does not cross the glass sheet, but licks the two surfaces of the sheet. When we place an oil drop on the sheet, the discharge will certainly pass through the sheet. | |||
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School Azuni |
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Function To show the ignition of a gas mixture thanks to an electric discharge. | |||
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Description It is formed by a little metallic container in which we introduce a gas mixture, airtightly closed by a cork. There is also a little spark gap with two brass spheres that communicating with the inside. | |||
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School University (1), Spano (2) |
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Function To show the ignition of a gas mixture thanks to an electric discharge. | |||
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Description It is formed by a brass tube with a polished wooden handle. Near the closed end an ebonite cylinder crossed by a brass wire is fixed. The brass wire ends near the opposite side of the tube and carries an outside sphere. We fill the tube with a mixture of hydrogen and air. We close with a cork and we bring it near the conductor of an electrostatic machine. The external discharge is repeated in the internal interruption and it provokes the ignition of the mixture. | |||
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School Spano |
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Function The apparatus shows small electric discharges. | |||
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Description Some strips of silver paper that form a winding line are put on a rectangular glass sheet that is placed vertically on a wooden basis. If we connect the ends to an electrostatic machine, we can see very effective sparks in the interruption. | |||
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School University (1), Castelvė (2), Spano (3) |
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Function To show electric discharges across low pressure air. |
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Description It is formed by a glass insulating ball, with a key and a screw connection to connect it to a pneumatic pump and by a cast iron basis polished with emery that is possible to place it on the plate of a pneumatic pump. The two conductors end with 18 mm spheres. One can be substituted by a point. The above conductor slides at friction along the axis of a set of leather disks, pressed as a gland, that assures a perfect seal. | |||
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School Spano |
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Function To show the thermal effects of the electric discharge. | |||
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Description A glass ball is welded to a thin glass tube that ends in a funnel. On the ball a nickel silver coil is suspended horizontally, connected to two external binding posts. We connect the coil to the external armatures of the conductors of an electrostatic machine across the posts, leaving a small interruption. The tube is fixed on a wooden table inclinable with a hinge on the horizontal basis. By introducing a coloured liquid into the tube and starting the electrostatic machine, we can observe the displacement of the liquid column because of the coil heating. The same apparatus can be used for Joules effect on the electric current. | |||
