Simulation 1: Electricity
Perhaps the most useful and integral
relationship of electricity is the relationship between voltage, current, and
resistance in an electrical wire. Voltage is the difference in electrical charge
between any two points. It can be measured across an appliance or a voltage
difference can be created by a battery. Current is the flow of charge through a
wire. Finally, the resistance is the amount of attenuation a wire or circuit
component applies on a current. The relationship between these three variables
is useful in order to understand Alexander Graham Bell's design. Try to
determine this relationship using the following questions as guidelines.
- For a constant voltage, would an increase in
resistance increase or decrease the current?
- For a constant resistance, a greater voltage would
induce a larger or smaller current?
Once this page
is done loading, a circuit should appear in a window. This circuit can be used
to test your hypothesis. The static, non chargeable battery is indicated by the
symbol 
and induces the labeled
voltage into the circuit. If there is an arm{ 
}then the battery is chargeable.The 
symbol is a resistor with a variable
resistance. The resistance can be controlled by the up and down arrows that are
located below the resistor. Clicking on the appropriate arrow will change the
resistance, and the current value of the resistor is indicated to the right of
the arrows. Finally, an ammeter is included in the circuit to measure the
current passing through the circuit. It is assumed that the wires have no
resistance, although this is not the case in reality.
As the
demonstration above shows, the voltage is equal to the product of the resistance
and current. Therefore, a decrease in resistance should increase the current for
a given voltage.
