Free Body Diagrams, Day #2

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Students will be able to identify the forces acting on an object, draw them in a free body diagram and identify whether the object is in a state of equilibrium.

Big Idea

Students have lots of practice with free body diagrams.

Physics Families

10 minutes

The goal of this lesson is to give students more practice with free body diagrams. Since we use free body diagrams a lot throughout this unit and the next unit, it is important that students are able to create a free body diagram and as well as what forces act on objects in a given situation. This lesson really helps student to be able to develop and use models when given a situation. 

To start out the lesson and the week, I have students get into their Physics families for a social activity. I believe that m students tend to work better when we start out the week with an activity that has nothing to do with physics and more with getting to know other group members better. The activity I have them participate in today is a competition where each Family answers 10 trivia questions about a random topic. Today's random topic is Oreos Trivia. I choose this activity because every one has a pretty even playing field and it is a good way to build up the teamwork in each family when they work together. I use Socrative's Space Race to track how students do and to tell which team wins. Each team has one chromebook open to the site and they have 5 minutes to complete the questions. I like to use the Space Race because each team gets a color and they can see their progress on the projector screen as seen below. After students are finished, I have them say goodbye to their families and return to their assigned seats. 

Free Body Diagram WS #1 Mega-Whiteboard

25 minutes

After Physics Families, I ask students to take out their homework from the last lesson (Worksheet #1 Free Body Diagrams). To go over the problems, I ask 10 students to come up to the board and write their answers on the board as a Mega-Whiteboard to go over the answers more quickly than an individual whiteboard session. I randomly select these 10 students from a set of cards that has each students name on it. I randomly select students to keep them engaged and making sure that they are completing their homework.

After all of the answers are on the board, I ask my students to check the answers by going over them 2 problems at a time. The board is set up so that there are two problems in each column. As we go over each pair of problems as a class, I have students to check their answers with the ones on the board and to ask questions if their answers do not match. To review the problems, I ask students to recall what forces are acting on each object and how we know if the object has a net force and whether it is in a state of equilibrium. We continue to go over these problems until we have looked over all of the answers. I review the answers this way because this is their first attempt at drawing free body diagrams so it is a lower risk way to go over their homework while still giving me an opportunity to see how the students are doing and to give students an opportunity to ask questions.

Free Body Diagram WS #2

35 minutes

When we have finished going over Worksheet #1, I ask students to work on Worksheet #2 Free Body Diagrams. Worksheet #2 gives students more practice with drawing free body diagrams. I ask students to try to complete these problems similar to the problems on Worksheet #1 from the previous lesson. These problems provide students with situations that a varied, real-life situations instead just a box. I want them to have more practice with these diagrams after what they have learned with going over the answers to Worksheet #1. 

Students work with the other people at their table as I walk around the room to answer questions. I want them to work as a group to make sure that they all agree as they go through the problems since they will be whiteboarding the problems in the next lesson. I have students work with their groups to complete the worksheet for the remainder of the class period.