Words related to static
Spark, responsible for the majority of industrial fires and explosions where static electricity is involved. Sparks occur between objects at different electric potentials.
Good grounding of all parts of the equipment and precautions against charge buildups on equipment and personnel are used as prevention measures. A static discharge in the presence of air or oxygen can create ozone. Exposure to ozone creates deep penetrative cracks in critical components like gaskets and O-rings. Fuel lines are also susceptible to the problem unless preventive action is taken. Preventive measures include adding anti-ozonants to the rubber mix, or using an ozone-resistant elastomer.
The energy stored as static electricity on an object varies depending on the size of the object and its capacitance, the voltage to which it is charged, and the dielectric constant of the surrounding medium. For modelling the effect of static discharge on sensitive electronic devices, a human being is represented as a capacitor of 100 picofarads, charged to a voltage of 4000 to volts. When touching an object this energy is discharged in less than a microsecond.
The effect is most pronounced when the neutral object is an electrical conductor as the charges are more free to move around. Careful grounding of part of an object with a charge-induced charge separation can permanently add or remove electrons, leaving the object with a global, permanent charge. This process is integral to the workings of the Van de Graaff generator, a device commonly used to demonstrate the effects of static electricity.
Fires from cracked fuel lines have been a problem on vehicles, especially in the engine compartments where ozone can be produced by electrical equipment. A Van de Graaff generator is an electrostatic generator which uses a moving belt to accumulate electric charge on a hollow metal globe on the top of an insulated column. It produces very high voltage direct current (DC) electricity at low current levels. It was invented by American physicist Robert J. Van de Graaff in 1929.
What does it mean if something is static?
adjective Also stat·i·cal. pertaining to or characterized by a fixed or stationary condition. showing little or no change: a static concept; a static relationship. lacking movement, development, or vitality: The novel was marred by static characterizations, especially in its central figures.
Fluids having conductivity above 50 pS/m are called non-accumulators. In non-accumulators, charges recombine as fast as they are separated and hence electrostatic charge accumulation is not significant. In the petrochemical industry, 50 pS/m is the recommended minimum value of electrical conductivity for adequate removal of charge from a fluid.
Static electricity is thought to be a particular hazard for astronauts on planned missions to the Moon and Mars. An important concept for insulating fluids is the static relaxation time. This is similar to the time constant τ (tau) within an RC circuit. For insulating materials, it is the ratio of the static dielectric constant divided by the electrical conductivity of the material.
The excess charge in a fluid dissipates almost completely after four to five times the relaxation time, or 90 seconds for the fluid in the above example. Many semiconductor devices used in electronics are very sensitive to the presence of static electricity and can be damaged by a static discharge. The use of an antistatic strap is mandatory for researchers manipulating nanodevices.
Example sentences from the Web for static
When the materials are separated they retain this charge imbalance. Static electricity is the result of an imbalance between negative and positive charges in an object. These charges can build up on the surface of an object until they find a way to be released or discharged. Rubbing certain materials against one another can transfer negative charges, or electrons.
Non-polar liquids such as gasoline, toluene, xylene, diesel, kerosene and light crude oils exhibit significant ability for charge accumulation and charge retention during high velocity flow. Electrostatic discharges can ignite the fuel vapor.When the electrostatic discharge energy is high enough, it can ignite a fuel vapor and air mixture. Different fuels have different flammable limits and require different levels of electrostatic discharge energy to ignite. The ability of a fluid to retain an electrostatic charge depends on its electrical conductivity.
- While the details are unclear and remain a subject of debate, the initial charge separation is thought to be associated with contact between ice particles within storm clouds.
- The discharge superheats the surrounding air causing the bright flash, and produces a shock wave causing the clicking sound.
Materials are made of atoms that are normally electrically neutral because they contain equal numbers of positive charges (protons in their nuclei) and negative charges (electrons in “shells” surrounding the nucleus). The phenomenon of static electricity requires a separation of positive and negative charges. When two materials are in contact, electrons may move from one material to the other, which leaves an excess of positive charge on one material, and an equal negative charge on the other.
The lightning bolt is simply a scaled-up version of the sparks seen in more domestic occurrences of static discharge. The flash occurs because the air in the discharge channel is heated to such a high temperature that it emits light by incandescence. The clap of thunder is the result of the shock wave created as the superheated air expands explosively.
Electrons can be exchanged between materials on contact; materials with weakly bound electrons tend to lose them while materials with sparsely filled outer shells tend to gain them. This is known as the triboelectric effect and results in one material becoming positively charged and the other negatively charged. The polarity and strength of the charge on a material once they are separated depends on their relative positions in the triboelectric series. The feeling of an electric shock is caused by the stimulation of nerves as the neutralizing current flows through the human body.
While the details are unclear and remain a subject of debate, the initial charge separation is thought to be associated with contact between ice particles within storm clouds. The static charge in air typically breaks down in this way at around 10,000 volts per centimeter (10 kV/cm) depending on humidity. The discharge superheats the surrounding air causing the bright flash, and produces a shock wave causing the clicking sound.
For hydrocarbon fluids, this is sometimes approximated by dividing the number 18 by the electrical conductivity of the fluid. Thus a fluid that has an electrical conductivity of 1 pS/m has an estimated relaxation time of about 18 seconds.
(See Reference below in Scientific American) The potential difference achieved in modern Van de Graaff generators can reach 5 megavolts. A tabletop version can produce on the order of 100,000 volts and can store enough energy to produce a visible spark. Small Van de Graaff machines are produced for entertainment, and in physics classrooms to teach electrostatics.
The spark associated with static electricity is caused by electrostatic discharge, or simply static discharge, as excess charge is neutralized by a flow of charges from or to the surroundings. Static electricity is an imbalance of electric charges within or on the surface of a material.
Further precautions can be taken by taking off shoes with thick rubber soles and permanently staying with a metallic ground. c) Static electricity is the result of an imbalance between negative and positive charges in an object. Brush discharge occurs from a nonconductive charged surface or highly charged nonconductive liquids. Further, because surfaces have a maximal charge density, an area of at least 100 cm2 has to be involved.
For example, if you rub your shoe on the carpet, your body collects extra electrons from the rug. The electrons cling to your body until they can be released as the case when you touch a metal door handle. Static electricity is basically an imbalance of electric charges within or on the surface of a material.
The charge remains until it is able to move away by means of an electric current or electrical discharge. Static electricity is named in contrast with current electricity, which flows through wires or other conductors and transmits energy. Conductors allow an electric charge to pass through them, but insulators do not. Objects can be positively charged, negatively charged or neutral. Due to the extremely low humidity in extraterrestrial environments, very large static charges can accumulate, causing a major hazard for the complex electronics used in space exploration vehicles.
Electrostatic discharge while fueling with gasoline is a present danger at gas stations. Fires have also been started at airports while refueling aircraft with kerosene. New grounding technologies, the use of conducting materials, and the addition of anti-static additives help to prevent or safely dissipate the buildup of static electricity. Discharge of static electricity can create severe hazards in those industries dealing with flammable substances, where a small electrical spark might ignite explosive mixtures.
The familiar spark one sees of a static shock–more specifically, is an electrostatic discharge– caused by the neutralization of charge. A charged object brought close to an electrically neutral object causes a separation of charge within the neutral object. Charges of the same polarity are repelled and charges of the opposite polarity are attracted. As the force due to the interaction of electric charges falls off rapidly with increasing distance, the effect of the closer (opposite polarity) charges is greater and the two objects feel a force of attraction.
While the total energy is small, on the order of millijoules, it can still damage sensitive electronic devices. Larger objects will store more energy, which may be directly hazardous to human contact or which may give a spark that can ignite flammable gas or dust. A static electric charge can be created whenever two surfaces contact and separate, and at least one of the surfaces has a high resistance to electric current (and is therefore an electrical insulator). The familiar phenomenon of a static shock – more specifically, an electrostatic discharge– is caused by the neutralization of charge. The flowing movement of flammable liquids like gasoline inside a pipe can build up static electricity.