The force of this push is measured in volts.
The word volts comes from the name of the Italian who invented the first battery—Alessandro Volta.
The more volts a battery has, the stronger its push.
In a copper wire (A), some electrons move freely in all directions.
When a battery is connected to the wire (B), the battery pushes the electrons in the same direction.
An electric current can now flow along the wire.
When we do experiments with electricity, we use small batteries.
These batteries give a push of 1.5, 6.0, or 9.0 volts.
We describe this as the voltage of the battery.
This voltage is printed on the side of the battery.
The voltage of the power line to your home is much higher.
The voltage of the electricity flowing through the wires in most homes is at least 110 volts and may be as high as 220 or 240 volts.
A voltage of more than 100 volts is enough to push electrons through your body.
If a strong electric current passes through your body, the shock will hurt you badly and could easily kill you. So you must always use low-voltage batteries for your electrical experiments.