To use a voltmeter to measure the voltage across a metal wire and an ammeter to measure the current passing through the wire, and:
The main variables in a science experiment are the independent variable, the dependent variable and the control variables.
The Independent Variable is what we change or control in the experiment.
The Dependent Variable is what we are testing and will be measured in the experiment.
The Control Variables are what we keep the same during the experiment to make sure it’s a fair test.
In this experiment the:
These are kept the same by not changing the wire during the experiment, by keeping the current small and opening the switching between readings.
Remember - these variables are controlled (or kept the same) because to make it a fair test, only 1 variable can be changed, which in this case is the current.
As the current increases, the voltage will also increase.
Greater current will mean that more charge flows.
This means that more energy can be converted from electrical energy to other forms of energy and so voltage increases.
|Water||Electric shock||Do not set up the experiment near taps, sinks etc.|
|Wire gets hot||Minor burns||Do not handle the wire. Switch off between readings.|