Eh, electricity works very simply.
First, 3 things, U = R * I.
U = Voltage (Volts), the force of what's wanting to go through (this isn't the amount of electricity, it's the force it's pushing with).
R = Resistance (Ohm), goes without saying.
I = Current (Amps), how much electricity is flowing.
This leads into P = U * I.
P = Power (Watts), the electricity itself, knowing this is knowing the effect, like heat.
Then there's the polarities of electricity, which is even simpler.
Positive wont move, but attracts the negative.
Negative moves, and is attracted by the positive.
There's also a last thing, Ground.
Ground is neutral, and interacts with both, if it's in contact with positive, it acts as negative, and if it's in contact with negative, it acts like positive.
Though this is at about half the power, as it's already neutral.
Electricity doesn't like unbalance, that's why electricity flows, to become neutral.
All electricity strives for balance, and may achieve so, violently (short circuit).
Short circuit is a connection between positive and negative with little to no resistance.
Turn U = R * I into I = U / R, and since resistance is close to zero in short circuits, the current is very high.
And since Power is Voltage multiplied by Current, and Power is heat, that's why it often ends up generating enough heat to vaporize metal.
Actually, time for numbers.
Let's say we have an outlet with 230 Volts, an appliance may have 20 000 Ohm, so finding the current is easy.
I = 230 / 20 000 | I = 0,011 5 | P = 230 * 0,011 5 | P = 2,645.
Now let's say someone cut the live cord with a pair of scissors, the resistance would drop to... let's say 10 Ohm.
I = 230 / 10 | I = 23 | P = 230 * 23 | P = 5 290.
That's jumping from barely noticeable heat, to electrical furnace. And depending on the distance of wire from the outlet to the power plant, it can range from harmless, to fire hazard, to vaporized scissors.