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

Day 75: HTML5, iPads and Simulations

Science 8 – Today was one of those rare days when your students actually put an iPad to good use.  I get so frustrated with the concept of the iPad (and Chromebook), as they are simply not good investments for schools that have science classes.  However, today the kids go to use a phet simulation that works with HTML5, which means it works with the iPad.

The activity was very simple.  The students played with the simulation which had them mixing the three primary colours, and using filters to block out colours.  From their explorations the students were able to clearly say that white light is a mix of all other colours, that filters block all colours except that the colour of the filter itself, and that all colours can be made from mixing red, blue and green. Next day we will look more closely at the electromagnetic spectrum, light spectrum, and wavelengths.  From that the students will have more complete picture of what a “colour” is.