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Physics {Electricity Part II Summer} ⚡ - Coggle Diagram
Physics {Electricity Part II Summer} ⚡
Conductors and Insulators
Conductors
- allows charge (electrons) to flow through it easily. Tend to be
metals
.
Insulators
- not very many free charges so does not all charge (electrons) to flow through it easily. Plastics, rubber, glass and wood are some examples
Metals are good conductors because they are made of a positively charged ions and free to move delocalised electrons which can carry current (rate of flow of electrons)
Insulators can be charged by friction (static electricity)
Investigate how insulating materials can be charged by friction
DORIC
D: charge of rod O: insulating rod- polythene, glass,wood R:// I: material of rod C: time spent rubbing, same type of cloth, length of rod
Method
Hold a polythene rod by its center, and rub both ends with a cloth.
Suspend it from a stand with a cradle and a nylon thread.
Take a {perspex} rod and rub it with another cloth.
Without touching, bring it up to the ends of the polythene rod.
Record your observations 6. Repeat with different materials.
. If the material is
repelled
from the polythene rod, the material is negatively charged. If the material is
attracted
, the material is positively charged.
With the polythene rod, the electrons move from the cloth to the rod. (polythene rod- negatively charged and cloth- positively charged)
With the acetate rod, the electrons move from the rod to the cloth. (acetate rod- positively charged and cloth- negatively charged)
Charges
like charges repulse (+/+) (-/-)
unlike charge attract (+-)
Static Electricity
Insulators can become electrically charged when rubbing certain ones together (friction). One object becomes negatively charged and the other positively charged because negatively charged electrons are transferred from one to the other.
Dangers
Fuelling Aircraft/Tankers
- Fire/Explosion, static electricity build up from friction between the fuel and pipe causes the fuel to become negatively charged.
Solution
A bonding line (copper wire conductor) 'earths' the vehicle by carrying the charge from the fuel to the earth to avoid any sparks.
Uses
Photocopiers
- Replicate Original Image, og image projected onto positively charged copying plate, where there is light the charge is leaked away, negatively charged toner is attracted to the shadowed parts of the image, paper placed on top of toner and heated to stick with a copy of the og image.
Inkjet Printers
- Make an Image, tiny droplets of ink are positively charged as they are heated through a nozzle through deflecting plates which direct it to the correct place because of their charges.
Insecticide Sprayers
- Cover Large Area, insecticide is positively charged as it leaves the sprayer, so like charges of the droplets repel covering the large area and are attracted to negative charges of the earth.
Painting Bike/Car Frames
Cover Large/Hard to Get to Area, paint is positively charged coming out of sprayer, and frame is negatively charged.The paint droplets are attracted to the unlike charges and cover the whole of the frame.
Example Polythene Rod and Cloth
The rod loses electrons, the cloth gains electrons. The rod becomes positively charged, and the cloth becomes negatively charged.
