9.2 Flashcards
what is spark and how is it formed?
spark is a charge moving through the air heating up the air, spark is formed when enough charge is build up due to friction
does air conduct electricity
it takes a lot of charge for air to conduct electricity
what happenes in a thundercloud
many small bits of ice (frozen raindrops) bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from these points eventually connects with a charge reaching down from the clouds
what is lightning
lightning is spark from clouds
how can lightning harm a person?
lightning can be very dangerous, if it strikes the person it can break their bones or even kill them, the charge travels from the person to earth the charge can interferre with their heart.
what is risk?
combination of the probability of something happening and the consequences if it did
what are lightning conductors and why buildings have them?
lightning conductors is a thick strip of metal such as copper running down the wall.the strip is attached to a copper plate buried underground .when lightning strikes the building the electrons flow down the strip to the plate and then to the ground the conductors can save the building from falling.
what is earthing and why is it used?
earthing is used to reduce the risk if an electric spark, this means u can connect it to earth with a conductor.
explain why there is a risk of sparks in cars or planes and how they can be reduced
the friction of the fuel moving down the pipe can cause a charge to build up.the fuel pipes are earthed b attaching a metal wire to the pipe any charge that builds up will flow down to earth, this reduces the risk
how do engineers reduce the risk of damage to the delicate components
engineers often wear special wristbands connected to a metal wire that goes to the ground any build up of charge flows down the wire to earth rather than through delicate objects
what is an electric spark
Anelectric sparkis an abruptelectricaldischarge that occurs when a sufficiently highelectricfield creates an ionized, electrically conductive channel through a normally-insulating medium, often air or other gases or gas mixtures
what does the severity of the shock depend on
- path of current through the body
- amount of current flowing through the body
- duration of shock current
what is an aed
An automated external defibrillator, or AED, is a machine that sends a high energy electric shock to the heart of a patient in sudden cardiac arrest (SCA). When a person is in sudden cardiac arrest, it means that their heart is in fibrillation. Fibrillation is a quivering or irregular heartbeat. One of the most effective ways to return a heart to a normal rhythm is with an AED. As the name suggests the AED defibrillates the heart.
does the heart stop beating in a sca
there is a misconception that the heart stops during an SCA. In fact it continues to beat in an irregular way (fibrillation) which prevents it from pumping oxygenated blood around the body to the brain and other vital organs. The AED is used to try and defibrillate the heart. It provides a shock to try and return the heart to its normal rhythm.
what are lightning rods
Lightning rods were originally developed by Benjamin Franklin. A lightning rod is very simple – it’s a pointed metal rod attached to the roof of a building. The rod might be an inch (2 cm) in diameter. It connects to a huge piece of copper or aluminum wire that’s also an inch or so in diameter. The wire is connected to aconductive gridburied in the ground nearby.
