Day 134 – Ohm’s Law


Science 9 – Students used the PhET DC Circuit Construction Kit to explore the relationship between voltage and current.  I had them use the simulator because it’s difficult to get good data using our ammeters and voltmeters.  I found that it was too easy for kids to make a mistake, and then they get data that doesn’t reveal any patterns.

Even though in grade 9 the kids are not especially great at deriving equations from a linear relationship, they are able to see a pattern and relationship using a data table, and can use words to describe this relationship.

For example, with the table below once they’ve collected data for current using different voltages, they will see that the voltage is always 100x the current.  From this, most kids decide to write something like “resistance times current is voltage”

 Resistor Size = 100 Ohm
 Current  Voltage