Nov. 7 – Measuring Voltage and Current

Learning Goals:  Understand how to measure electric potential difference and current.

Success Criteria:  Draw circuit diagrams with voltmeters and ammeters.  Solve problems involving current and electric potential difference.

Handouts: 

• Current and Potential Difference Problems

Today I went over how ammeters and voltmeters are connected to circuits.  Have a look at these diagrams to see the difference.

Here is a typical circuit with three bulbs in series.

 Here are different ways to use an ammeter to measure current.

 Here are different ways to use a voltmeter to measure electric potential difference.

Here is what a real voltmeter looks like:

The red input is positive and the black input is for the negative end of the battery.

Then we watched some Mythbusters!

Video: http://www.youtube.com/watch?v=SU7xkYmWwmQ

This video is very informative because it shows that even experts can make mistakes.  The first half of their experiment had a lot of mistakes and they needed a professional electrician to help them out.  Also, they keep on using the terms "amperage" and "voltage" the correct terms to use are "current" and "electric potential difference".

Homework:

• Complete the handout.