Electricity - Yr 8 Flashcards
What is static electricity?
Related to the forces between two objects which are charged
What is charge?
How positive or negative something is
How does something become charged?
Gain or lose electrons
What are the two ways that something can become charged?
Charging by friction
Charging by induction
Explain charging by friction
Uses friction to charge an object. If an insulator is rubbed with a cloth, it can either be charged by electrons moving from the cloth to the insulator (insulator becomes negatively charged) or electrons move from the insulator to the cloth (insulator becomes positively charged)
Do protons or electrons move when charging?
Electrons (Protons are always in a fixed position)
Explain charging by induction
By introducing a negatively charged object (A) to a neutrally charged object (B), and because like charges repel, the negative charges in object B move away from the negative charges in object A. As positive charges are always in a fixed position and so cannot move, one side of object B becomes negatively charged and the other side positively charges, as a result from inducing a charge from object B
What is an insulator? Give examples
A material that does not allow electricity to pass through - e.g. Plastic, rubber, wood
What is a conductor? Give examples
A material that allows electricity to pass though - e.g. Copper, iron, aluminium (any metal)
What does the term “earthing” mean?
Using an electrical conductor to provide a path for the charge to flow to the ground, preventing a build-up of static charge
Explain the formation of lightning
In clouds, water drops rub against each, creating static electrical charges. This charge builds up and creates a spark which attracts towards the Earth to neutralise the charge
Why is there a metal wire connecting the delivery tank to the fuel tank on a plane?
The wire provides a path for the electrons to travel to the ground, preventing any build-up of static charge that could create a spark that could cause an explosion if it came in contact with the fuel - earthing
Explain how static electricity can be used when spray-painting a car
The paint droplets are given a negative charge and the car is given a positive charge. As like charges repel, the paint droplets spread out in a fine mist, ensuring that the car surface has an even layer of pain and minimises waste
What is electrical charge measured in?
Coulombs (C)
Explain how static electricity can be used to filter smoke particles in a chimney
Smoke particles pass through a negatively charges grid and pick up a negative charge. The metal plates on the sides of the chimney are given a positive charge. As opposite charges attract, the smoke particles attract to the metal plates and so are not released into the air, reducing air pollution
