Teaching Strategies and Activities
As students will be building a device, the pacing of the lessons will be based on the learning speed of the students. While sharing video clippings for a given lesson, I will be using blended learning in the classroom. While playing a video, I will pause and explain all of the concepts related to the topic. Later, I will be using direct instruction to teach students the basic electronic components used to build the soil moisture sensor. Notes about each of the electronic components used will be shared, so students can easily identify the various parts and know their functions. Students will participate with their teams and build a soil moisture sensor, test it, analyze their results, and communicate their results to the class.
The first section of this unit will introduce students to the process of the Engineering Design Process, I will go over each of the steps involved which include the identification of a problem or need, the design criteria which define the physical and functional characteristics, the constraints which will be factors that limit the flexibility of the product, alternate designs that come up while engineers brainstorm, building a prototype, testing and evaluating the prototype using the design criteria, analyzing the test results, make design changes and retest, and to communicate the results.
Section two will focus on introducing students to the basic electronic components. To get started, I will conduct a demonstration of how a breadboard is used to make a LED light bulb glow, when it is connected to a battery and a resistor. I will conduct it in five steps, so it is easy for students to follow. Step 1; The battery pack’s red lead (+) is connected to the + side (red line) of the power bus on the right side of the breadboard. Step 2: Next a jumper wire is used to connect from the + side of the power bus (row 5) to row 5, column I. Step 3: Next, the longer lead (leg which is positive) of the LED bulb is inserted into row 5, column H, and the shorted lead (negative) is inserted into row 5, column E. Step 4: A resistor is connected from row 5 column B, to row 5 on the ground bus. Step 5: A black wire is connected from row 1 of the ground bus to the battery pack’s black lead (i.e. the negative charge). The student will be able to see that the light bulb glows when the circuit is completed! Students will then make use of a breadboard and create a circuit to light up a LED bulb.
Under section three, I will engage students in a short discussion about being team players and will create heterogenous groups of students so they can work together. In order to help students get started with building the soil moisture sensor, I will go over the slides on assembling the circuit from the sciencebuddies.org website, along with identifying each of the markings on the electronic components and also the instructions that need to be followed at the bottom of the slides.16Students will then assemble the circuit for the soil moisture sensor.
Section four, will focus on testing the device and analyzing the results. Students will test their device with dry soil and then with wet soil. When I tested by using drops of water, the LED stayed on initially for the first three drops of water for 50 grams of soil that I used to conduct the test. As soon as I added the fourth drop of water the LED light went off. I shifted the resistors and conducted the test three times and I got the same results. Students will be required to share their work with the class and communicate their test results. If a group of students get done with their work early, they will be able to go individually, to help other groups to identify any problem that they may be having and help them solve the problem.
Section five, will allow students to participate in a discussion on how they will dispose of electronic waste in a responsible manner without impacting the environment.
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