Resistance of Wire Investigation
Aim
To investigate the resistance of a metal wire depending on its length.
Introduction
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An electric current is the flow of microscopic particles called
electrons through wires and electronic components.
It is like the flow of water through pipes etc.
As water is pushed through pipes by a pump, electric current is pushed
through wires by a battery.
One thing we know is that like charges repel each other and unlike
charges attract. Two negatives will repel each other. A negative and a
positive will attract each other.
An electron has a negative charge.
The negative (-ve) terminal of a battery will push negative electrons
along a wire.
The positive (+ve) terminal of a battery will attract negative
electrons along a wire.
Resistance = Voltage/Current
In simple terms resistance is anything in the circuit, which slows the
flow down. Resistance is a force, which opposes the flow of an
electric current around a circuit so that energy is required to push
the charged particles around the circuit. The circuit itself can
resist the flow of particles if the wires are either very thin or very
long. Resistance is measured in ohms. The symbol for an ohm is OMEGA.
A resistor has the resistance of one ohm if a voltage of one volt is
required to push a current of one amp through it.
In all metals there is a sea of electrons flowing. This "sea" is all
the electrons from the outer shell of a metal atom. The electrons are
negatively charged and flow from negative to positive, as they are
attracted to that side. This is what allows electric current to flow
so well in all metals. When the free electrons collide when travelling
to the positive side this causes resistance rise.
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Resistance is the electrons (e-) finding it hard to flow
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There are many key variables in this particular experiment they are:-