## Ultimate STEM

Powerful Teaching Moments

Aurora has been a math and science teacher for 13 years at Brooks College Prep high school, teaching chemistry, physics, and mathematics. She graduated with B.S. in Civil Engineering (1981) from Philippines, M.A. in Education (2001) from Saint Xavier University, Chicago, and Master of Chemistry Education (2011) from Illinois State University. She is a lifelong learner who is curious and passionate.

## Amazing Teaching Moments

This lesson is an introduction to torque. The balancing demonstration is used to gain a concrete understanding of how balancing observations lead to mathematical models, for use to solve problems in different scenarios.

I started the lesson by asking a question, "Do you remember a fun seesaw ride with your friend"

While a majority of the students recalled their happy memories; I demonstrated using a set up consisting of a meter stick, cork, and pennies, on the table. "Today, you will search for balance," I stated. I asked the students to observe when the meter sticks were not balance, and when they were. I then noted their range of responses on the board.

To steer the discussion to the lesson at hand, I guided the students by asking, "Anything we can measure here?" From the length of the stick to the weight of the pennies, students started to churn all sorts of responses. We recalled a prior mass vs. weight lesson; upon which we established the pivot point, and observed twisting or rotating describing a torque, to then define torque as force time distance perpendicular to the direction of the force. One student repeated, "The lever arm was that distance from the pivot, and weight is a force." The discussion was starting to get through to them.

The students then worked in groups to balance the pennies from at least five different distances from the pivot. During this exploration, as a student playfully balanced the penny away from the pivot, I asked if there was a force in the penny.She replied, "I believe it has weight, but not force, I did not push it!" All of us laughed! I said, "When you dropped the penny of the floor, what was happening?"She replied, "Oh the gravity 'thingy' attraction toward the Earth." I explained that it is a force, due to gravity exerted on the object by the Earth, and exactly the same as weight. We used the mathematical model W=mg and F=mg (falling vertically).

And when every group had moved the pennies away and near the pivot, I riddle the entire class with questions on force, torque, distance from the pivot and their relationship. Then I asked them to finish collecting data and organize it using data table, with four columns, with a heading "#Penny," and distances from the pivot from the left and right sides. I guided the students to look for a consistent pattern using their data table. I said, "What does your data say?"

My students completed the whiteboard and reported it with the data table, description of patterns observed, a general statement describing the result, and translation of word into mathematical model. A quick question and answer time was given to each group presenter. The lesson ended with an exit question, which asked to estimate the mass of the meter stick using only a single penny, meter stick, and the cork. This was a way to test the students' understanding from the lesson today.

**Key Components for Ultimate STEM Lessons**

1) Safe classroom culture: Each lesson is dependent on students feeling confident that they can explore their ideas, make them public, and be supported in their efforts.

2) Simplistic: The lesson is easily set up and conducted in the classroom. Lessons also take familiar, readily available items and re-purposes them to achieve educational goals.

3) Students explore through collaborative Inquiry-based learning. Each lesson allows students to deepen their understanding while participating in constructing their own knowledge through collaborative hands-on activities.

4) Relevant, real-world centered (careers, cross curricular): These lessons are applicable to everyday life and are pertinent for effective relational teaching. Therefore, the lessons empower and prepare students to be globally competitive.

5) Shift from concrete to abstract ideas: Children learn concrete concepts by interacting with their environment. Through hands-on activities, students can connect their environment to abstract ideas in the content.

**Activities**

Materials: Meter Stick, Cork, Pennies
( or wood dowel and nuts can be another option) |
Balancing Act Between Equals Left Side of the Pivot = Right Side of the Pivot
(# of penny x distance from the pivot)left side= (# penny x distance from the pivot) right side. Can you find the mass of the meter stick in terms of number of pennies with the restriction of just using one penny? |