Ever wonder how lightning works? Scientists are still figuring it out, but what we do know is fascinating. Learn about positive and negative lightning, red sprites, blue jets, and ball lightning in this episode of SciShow! Hosted by: Michael Aranda Continue reading
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.
STAO Safety Chair
This TED talk demonstrates a novel and fun way to investigate series and parallel circuits using plasticine as the conductive medium. The Playful Learning Lab website provides sample activities, videos and recipes for making plasticine.
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
This is a fun and challenging inquiry activity in which students construct circuits with specific requirements.
This activity is part of STAO’s Connex series on scientific inquiry.
Click here for the complete activity
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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…
You just wanted to shuffle across the room in your pajamas and bunny slippers, but when you go to reach for the door knob… you get shocked! Continue reading