You will build a circuit and conduct a demonstration so your students can observe the relationship between voltage, current and resistance.
Set up a circuit as shown here:
Review the “Exploring Ohm’s Law” worksheet with students.
Using data from the table, have your students create a graph of voltage versus current (V vs. I). Make sure they label all parts of their graph. Explain what a line of best fit is and have your students draw one on their graph.
From the line of best fit, have your students calculate the slope of the line:
The resistance of a circuit is mathematically shown as an algebraic equation:
Compare the slope of the graphs your students created with the stated resistance of the resistor you used. The numbers should be similar (different numbers are a result of individual differences in choosing a line of best fit).
The relationship between voltage and current is Ohm’s Law, and the slope of the line from a graph of the two is the value of the resistance in the circuit. The Ohm’s Law equation can be represented in three ways:
Review the “Exploring Ohm’s Law” worksheets completed by your students, checking the accuracy of data recording, calculations and graphing.
Ohm’s Law represents the relationship between voltage and current. It is usually represented mathematically:
It’s necessary to convert milliamperes (mA) to amperes (A) when using Ohm’s Law. There are 1,000 milliamperes (mA) in one ampere (A).
In order to represent Ohm's Law in a graph, use a line of best fit. These are used to show trends between sets of data and to show the relationship between various points on a scatter plot. Scatter plot graphs are commonly used with real-life data where data can be affected by the environment of the experiment.
The relationship between the dependent and independent variables can be described as a straight line if the relationship is linear in nature (often shown as a straight line graph).