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OP53 The Effects of Electricity
describe the heating effect, the chemical effect, and the magnetic effect of an electric current, and identify everyday applications of these,
Heating effect,
Electricity is the flow electrons, as they move through a metal element that resists their movement, they impart their moving energy into the element. Like when you rub your hands together and friction resists the movement of the hands the heat up the same happens with the electrons.
All materials have some resistance, too much resistance and no current will flow, if there is not much resistance then the heating effect might not be noticed.
Examples of where this happen in our lives include ........ cooker, toaster, kettle, electric heater, hair straightener, light bulb. -
http://www.sei.ie/Schools/Secondary_Schools/Subjects/Physics/Unit_4_-_Electric_Effects/
To Demonstrate the heating effect
Get some steel wool, connect it to a power pack
Observe
magnetic effect of electricity
Battery 9V approx, switch, 3m of single core wire (bell wire), needle and thread,
tube with (diameter 50mm - 100mm) (2 litre cyclinder bottle of pop), 2 small (but similiar) pieces of wood to act as a base
To make the solenoid wrap the wire around the bottle a nnumber of times, taking care to leave 100mm at both ends to connect to the battery.
Use tape (or wax?) to keep the solenoid from unravelling.
remove the mould, and using the thread suspend the needle within the loop (prefereably in the middle)
connect the wire via the switch to the battery.
allow the needle to settle (stop swinging about)
close the switch (allow the electricity to go thru the solenoid)
observe
extensions
reverse the polarity of the battery. what do you expect?
make different diameter solenoids. what do you expect?
use different voltage size batteries what do you expect?
use a hall probe to measure the magnetic flux density
Electromagnets make
- Motors
- speakers
- Autolock doors
- security gates
work
the chemical effect
The passage of an electric current through some fluids causes a chemical change.
Electroplating is an example of the chemical effect of electricity.
This is when we take a base (cheaper) metal and coat it with a desired metal (e.g. Gold). The coating can be made to be thin but after a certain time the base metal is completly hidden.
there are 2 main reasons for electroplating metals,
- To Protect the metal underneath
- to give the product a more attractive finish
examples include
Galvanized Iron with Zinc
Jewellery Cutlery
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