Device and Method for Measuring Millikan Oil Droplet Equilibrium Voltage by Lowering Air Pressure

Abstract

The invention provides a device and a method for reducing air pressure measurement Millikan oil-drop balanced voltage, in order to reduce the effect on oil-drop balanced voltage measurement brought by oil-drop balanced acting force caused by air collision. The technical scheme is as follows: the device and the method are characterized in that an annular gasket is flatly laid on a top panel of an oil drop instrument, a notch of a cylinder rides between inner and outer pieces of a semicircle sealing gasket, and the cylinder is pressed tightly by hands, so that the other part of the cylinder is in tight contact with the annular gasket; a cross-shaped lever is rotated to move a piston structure to change the pressure of sealing gas, until Brownian movement of an oil drop cannot be observed; a piston moves, and the volume of the sealing gas is 10 to 100 times that of the inner volume of the cylinder. The beneficial effects are as follows: the balanced voltage of the oil drop can be more accurately measured; the semicircle sealing gasket rides at inner and outer sides of the notch of the cylinder, so that a self-sealing function is realized; the diameter of a fixing plate is less than that of the piston structure by 0.5 to 1mm, and the fixing plate is prevented from being in contact with the inner wall of a piston cylinder, so that friction is avoided; the piston is modified into a piston with a three-layered structure, so that the gas tightness of the piston is facilitated; normal pressure is easy to restore.

Description

technical field [0001] The invention relates to the field of measurement of physical quantities. Background technique [0002] When judging the force balance of an object, the judgment standard is generally based on whether the object is at rest or in uniform linear motion. In most cases, whether the object is at rest is used to judge whether the object is in force balance (the resultant force is 0). [0003] The diameter of the Millikan oil droplet is roughly on the order of microns, and the distance between air molecules is roughly on the order of nanometers. When the oil droplet is close to equilibrium, the oil droplet is equivalent to a suspended particle. There will be Brownian motion, that is, irregular and chaotic movement of the droplet particles, which makes it difficult to judge the force balance of the oil droplet. For relatively large oil droplets, the unbalanced force of air molecules on the oil droplets is relatively small compared to the gravity of the oil dr...

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Problems solved by technology

[0003] The diameter of the Millikan oil droplet is roughly on the order of microns, and the distance between air molecules is roughly on the order of nanometers. When the oil droplet is close to equilibrium, the oil droplet is equivalent to a suspended particle. The droplet particles will appear Brownian motion, that is, irregular and chaotic movement, which makes it difficult to judge the force balance of the oil droplet

For relatively large oil droplets, the unbalanced force of air molecules on the oil droplets is relatively small compared to the gravity of the oil droplets (that is, the mass and inertia are large), and the stability of the suspension is relatively good. However, due to the large oil droplets and large mass , The effect of air molecules is small, the speed of falling is relatively fast (that is, the time of falling is relatively short), and the error of measuring its falling time is relatively large (subject to the human physiological reaction speed of 0.1 seconds, because the oil droplets are relatively small, photoelectricity cannot be used) Doors and other devices for timing, generally use a microscope to magnify and manually judge its position and operation start timing and operation stop timing); when the oil droplet is relatively small, the imbalance caused by the collision of air molecules is relatively large, and Brownian motion Obviously, it is impossible to accurately determine whether it is in a balanced state, resulting in a relatively large measurement error of the balanced voltage

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