Teaching Electricity Strategies – submitted by Dave Gervais

This is the third part of a series of blogs written to suggest teaching methodology for the topic “Electricity”.  Brief descriptions of Parts One and Two have been included below.

Part One: Models: In the picture below, soup cans are used to represent students.  Actual students formed in a circle will pass and receive playing cards (electrons).  Students pass the cards on command, when the teacher says “PASS”.  A potential boost occurs at the battery, a potential drop at the light bulb.  Students are assigned roles at a switch, a load, or a battery.  At a load, the student can be asked to twirl at each pass to simulate work being done.

Click here to download entire document 

Thanks for sharing Dave!

Electricity: Alternative to Traditional Bulbs – submitted by Dave Gervais

The traditional incandescent bulbs used for teaching series and parallel circuits are rated for 3 V or 6 V. The problem is that many power supplies can generate higher voltages. As a result, it is common to have many blown bulbs. With several sections teaching this unit, bulbs can quickly become in short supply. Bulb replacements can cost $1.00 each, and often are included in the general department order at the end of each semester.

LED as an alternative: LED lights are rated for low voltages (3 V).  However, by adding a small resistor (390 ohms) to one of the legs, the LED can be used at excessive electric potentials. After adding the resistor, the LED was successfully used at 13.88 V, the maximum value for my power supply.

Construction: The resistor and LED wire were twisted together. To be consistent, the resistor wire was attached to the anode (+) leg of the LED. To identify this, the LED was held up to a light. The smallest metal in the LED bulb is the anode (+). Solder paste was added to the two twisted wires. Using a pencil style soldering gun, the smallest drop of solder was added on to the soldering iron tip. The tip touched the paste and they were instantly soldered. Start to finish the whole process took less than a minute.

The advantages: The LED’s now can function at higher voltages, the legs can easily fit into breadboards or can be alligator clipped into circuits, and they are cheap. A kit with 100 LEDS, and 390 ohm resistors costs less than $12.00 from Qkit Electronics, Kingston Ontario.

 

 

 

This was initially presented at OAPT 2018 at Western University, London Ontario.

Dave Gervais

STAO Safety Chair

Don’t Be Shocked—Electrical Safety – Flinn Scientific Canada

Accidents involving electricity can cause shock, burns, and even death. Reviewing and following a few basic rules will help you improve electrical safety when working with hot plates, electrophoresis equipment, power supplies, Van de Graaff generators, etc. Continue reading

Building an Electric Car in Grade 9 Science – Student Activity

 

The Focus on Inquiry:

This guided inquiry project was designed to provide students with the challenge of creating a fully-electric car.  The students were provided with a motor, photographs of sample electric cars, an outline of the criteria their car was to meet, and a rubric as a marking scheme.

The Inquiry Project:

The project was discussed and proposed at the beginning of the physics unit of study in grade 9 applied science. 

Students were tasked with completing three main components:

I.       A Thought Book

This is where the students formulated questions, made hypotheses, and made predictions about their project prior to beginning construction of their electric car.  The Thought Book took the form of pre-formatted Google Slides that the students shared with the teacher and the rest of their peers.  The students completed different ‘pages’ of the Thought Book as they progressed through different stages of the inquiry project.  They also used the Though Book to gather, organize and record information during their ‘build days’.

II.     A schematic of their circuit

This is where the students communicated their understanding of how electricity moves through their circuit.  Students were asked to communicate their results in appropriate key terms (ie. source, load, conductor, insulator, switch).

III.    Reflection questions

These questions were designed to have students reflect on their learning, analyze their outcomes, describe their challenges and how they surmounted them.

This activity is part of STAO’s Connex series.  For more details about this activity, including all you need to use it in your classroom go to the STAO Connex page…