This is the final lesson in a STEM design cycle where student investigate balance by first experimenting with balance scales and then design and build towers to meet specific guidelines.
This lesson aligns to Essential Standard 1.P.1.3, 'Predict the effect of a given force on the motion of an object, including balanced forces'. This lesson is important because it gives students a change to evaluate their designs and then change them--and we all want a chance to improve! Then, they communicate their results from the entire design cycle. This lesson is designed to take two 35-minute class periods.
*1 STEM Lab Balance Design Rubric per student
*Building materials (same materials they used to build previously)
*Photographs from towers, printed for each student if possible (not necessary to be in color!)
*iPads or other recording devices
*1 Balance scale Communicate Sheet per student
The fourth step in the engineering design process that we use is Evaluate. Today, I start the lesson by reviewing the evaluation rubric that my students have seen each day. It is not an "Assessment" --it is an "Evaluation" because the students are determining how well they met the criteria on the rubric. I say,
"Boys and girls, I have given each of you a photograph of your towers that you built yesterday. Now, you are going to evaluate your tower by yourself. You also have to evaluate how well you worked with your partner. Let me remind you how to do this. As I read each question, you mark 'Yes' or 'No' with an X like this..."
Then, I show how to add up the final score. I collect the rubrics so that I can look at them just to check in with how my students are doing with self-evaluation, and then I will return them and they will be added to their science journals.
After I have the rubrics, I say,
"Who had a tower that was successful--in other words, it was 2 feet tall and had 10 objects, and could balance? What did you do to make it work?"
I want students to share their strategies that worked because I am going to give my students another try at building today, to see if they can change their plans and increase their balanced tower. So, after some students share, I say,
"Today, you are going to try again with the exact same materials, to make a taller, more balanced tower. What will probably happen if you do the exact same thing? You'll get the same result! So, try different things today! If you have a success, make sure I get a good picture!"
As the students work, I listen out for them changing their language and trying the new strategies to see if they are adjusting their thinking. Good scientists try new things and learn from colleagues!
After about 20 minutes, I tell them it is time to clean up for today and that tomorrow we will finish the design cycle with "Communicate!".
The final step in our design process is 'Communicate' and my students always communicate in 2 different ways, typically one written and one verbal. This is just my way of making sure that everyone really gets to express what they have learned! Sharing and communicating ideas supports Science and Engineering Practice 8. First, my students are going to share using the document camera about their experiences. I ask each pair to show their plan on the document camera and then talk about something that was challenging that they had to work together on to figure out.
After we finish that, my students write two things they learned about balance during this STEM cycle. With the written work, I display it in our classroom for the students to read and be proud of!