P4 - Problems with Static Electricity Flashcards
How are electric charges involved in attracting dust?
- Dust particles are charged and will be attracted to anything with the opposite charge.
- Unfortunately many objects around the home are made out of insulators that get easily charged and attract dust particles, making cleaning harder.
How are electric charges involved in clothing clings and crackles?
- When synthetic clothes are dragged over each other ( like in a tumble drier) or over your head, electrons get scraped off, leaving static charges on both parts.
- This leaves to attraction and little sparks or shocks as the charges rearrange themselves.
How are electric charges involved in shocks from door handles?
- Walking on a nylon carpet whilst wearing shoes with insulating soles, will result in charge building up in your body.
- If you touch a metal door handle or water pipe, whilst you have charge, the charge flows via the conductor and you get an electric shock.
What are some ways in which static electricity is a nuisance ( 3 )?
- Attracting Dust
- Clothing clings and crackles.
- Shocks from Door Handles.
How can large amounts of static charge build up on clothes?
- A large amount of static charge can build up on clothes made out of synthetic materials if they rub against other synthetic fabrics.
How can static charge build up clothes be dangerous?
Eventually, charge can become large enough to make a spark, which is dangerous if it happens near any inflammable gases or fuel fumes.
How does static charge build up in paper rollers and grain chutes?
As fuel flows out of a filler pipe, or paper drags over rollers, or grain shoots out of pipes, then static can build up.
How can static charge buildup in paper rollers and grain chutes be dangerous?
- This can easily lead to a spark and might cause an explosion in dusty or fumey places, like when filling up a car with fuel at a petrol station.
How can dangerous sparks be prevented?
- Dangerous sparks can be prevented by connecting a charged object to the ground using a conductor ( e.g. a copper wire ), this is called earthing.
Why does Earthing prevent charge buildup?
- It provides an easy route for the static charges to travel into the ground. This means no charge can build up to give you an electric shock.
Where may static charges be a big problem?
Static charges are a big problem in places where sparks could ignite inflammable gases, or where there are high concentrations of oxygen ( e.g. in a hospital operating theatre ).
Why must Fuel tankers be earthed?
- Fuel tankers must be earthed to prevent any sparks that might cause the fuel to explode.
- Re-fuelling aircraft are bonded to their fuel tankers using an earthing cable to prevent sparks.
How do Anti-Static sprays work?
- Anti-static sprays and liquids work by making the surface of a charged objects conductive, this provides an easy path for the charges to move away and not cause a problem.
How do Anti-static cloths work?
Anti-static cloths are conductive, so they can carry charge away from objects they are used to wipe.
How insulating mats & shoes work?
They have insulating layers such as soles, they prevent static electricity from moving through them, so they stop from getting a shock as long as you don’t touch anything metal.
