We began with the students mentioning the examples of oscillation in daily life. The word 'oscillation' is not familiar to them, so I told them it has the same meaning as vibration. Once I mentioned the word vibration, they began to say the swings, the guitar strings, springs, and so on.
Then I tell them the term 'Simple Harmonic Oscillation'. I explained the properties of speed and acceleration in Simple Harmonic Oscillation. I took the simple pendulum as an example. So as I was demonstrating the simple pendulum, they observed the movement. Here is the result of discussion look like on board.
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| Speed and acceleration change in Simple Pendulum |
I told them that all simple harmonic motion follows the same pattern. Then I distributed a worksheet for them to identify simple harmonic oscillation in several cases. You can download the worksheet in the following link.
Identifying Simple Harmonic Oscillation free download pdf
I got students do them in groups of 3 or 4 students for about 10 minutes. After they finished, I discussed each cases with them. The answer key is in the end of this post.
The answer for simple pendulum and spring-mass system is straight forward since they already see the demonstrations. Because my students are non-English-native speakers, they need time to check the meaning of several words in the internet.
For earth motion around the Sun, rotation of Earth, and Merry-go-round, I ask students to compare carefully with the patterns. Is there any point in which the object has zero speed? Of course not, because they are circular motion. Here, students can linked and differentiate between circular motion and simple harmonic oscillation. When they spot a motion is circular, they directly answer not simple harmonic motion.
For Dribbling basketball, a child on trampoline, and Jane running back-and-forth between two points, they need extra discussion. In these cases, the motion almost looked like simple harmonic, but again looking at the pattern (especially the acceleration), we can agree that those three are not simple harmonic.
Over all students, around 90% of students understand the conclusion in the end of the class with the average got around 80% of total score.
Well, yes, I feel satisfied with the result.
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