Summary
In this lesson, students investigate what factors affect the force of gravity and use plotted data to determine graphically how each variable is related to the force of gravity. Students review their understanding of gravity and how to linearize a set of data. Students use a gravity simulation to collect data on what variables change the force of gravity and how they are related to the force of gravity. Students apply Newton’s Law of Gravitation to calculate values to predict the force of gravity, and students use plotted data to calculate the value of the gravitational constant.
Essential Question(s)
What variables affect the force of gravity? Why do objects attract each other? How do graphs show the relationships between different variables?
Snapshot
Engage
Students recall their prior knowledge about the force of gravity. Then students review how to linearize a set of data.
Explore
Students manipulate variables to determine how the force of gravity is affected by each independent variable. They use the relationships they find to develop Newton’s Law of Gravitation.
Explain
Students apply the universal law of gravity to calculate force, distance, or mass involved.
Extend
Students examine how the gravitational constant was originally calculated with a torsional pendulum. Students then use a set of data to calculate the gravitational constant and calculate the percent error to the accepted value.
Evaluate
Students demonstrate their understanding of the relationship between the variables that affect gravity through a conceptual question. Students demonstrate their understanding of the quantitative relationship by applying Newton’s Law of Gravitation.
Materials
Lesson Slides (attached)
Relationship Between Graphs Card Sort (attached, 1 per group of 3-4 students)
Relationships Between Graphs Teacher Guide (attached)
Gravity Simulation handout (attached, 1 per student)
Gravity Simulation Teacher Guide
Newton’s Law of Gravitation handout (attached, 1 per student)
Newton’s Law of Gravitation Teacher Guide
Finding the Gravitational Constant handout (attached, 1 per student)
Exit Ticket Solution Key (attached)
Class set of calculators
Student devices with internet access
Sticky notes (1 per group of 2-3 students)
Notebook paper
Pencils
Engage
25 Minute(s)
Use the attached Lesson Slides to guide the lesson. Display slides 1-4 to introduce the essential questions and learning objectives with students. Move to slide 5 and introduce the Justified True or False instructional strategy to students. Break students into groups of three to four and give groups two to three minutes per slide to evaluate each of the statements on slides 6-8. After each slide, pick a few groups to share their response and ask the rest of the class whether they disagreed or had used any other supporting evidence.
Display slide 9 and use the Card Matching instructional strategy to help students review the relationships between graphs and equations. Place students into groups of three to four and pass out the Relationships Between Graphs Card Sort cards. Provide about ten minutes for students to match the descriptions to the graphs. Assign each group one graph to write the original relationship between x and y on the board, on a piece of butcher paper, or in a google document to display to the class. Overlapping groups can verify that they agree with what is written.
Display slide 10 and have the groups spend three to four minutes discussing the question before asking the class to respond. Once students have answered correctly, display slide 11 and review the two steps to make the linear graph. See the attached Relationships Between Graphs Teacher Guide for a solution to the card sort.
Explore
30 Minute(s)
Display slide 12 and pass out the attached Gravity Simulation handout. Direct students to use their personal devices and access the online Phet simulation at the following link: https://phet.colorado.edu/en/simulations/gravity-force-lab.
Have students work in pairs to complete the online simulation and handout. Students should keep their handout for the Explain section of the lesson. More specific information is provided in the attached Gravity Simulation Teacher Guide.
Display slide 13 and have students use the Sticky Bars instructional strategy to build consensus on question 7 from the Gravity Simulation handout. Have students write down their equation on a sticky note and then have the first group stick their notes on the wall. The following groups either put their notes directly above the first group’s sticky note if it is the same equation or create a new column if it is a different equation. Once all of the groups are on the wall, have a quick class discussion to arrive at consensus about evidence for which one is the right equation.
Consider stopping at this point for the day.
Explain
50 Minute(s)
Display slide 14 and pass out the attached Newton’s Law of Gravitation handout. Use a modified version of the Pass the Problem instructional strategy to have the students work through the problems. First, break the class into six groups for the 6 problems on the handout. Assign each group a problem from the handout. Next break each of these groups into pairs. Provide about five to six minutes for students to record a response to their assigned question.
Collect all students' responses and sort them by question number; then display slide 15. Provide students with a set of responses based on the following order:
Problem 1 students look over problem 2.
Problem 2 students look over problem 3.
Problem 3 students look over problem 4.
Problem 4 students look over problem 5.
Problem 5 students look over problem 6.
Problem 6 students look over problem 1.
Give the combined groups 10-12 minutes to read over the responses and develop a consensus about how to get to the correct answer. Tell each group to elect one person to present the question and the solution, while the rest of the class takes notes over the solutions on their handout.
Consider stopping at this point for the day.
Extend
40 Minute(s)
Pass out the attached Finding the Gravitational Constant handout and display slide 16 to go over the I Notice / I Wonder instructional strategy. Display slide 17 and slide 18 and show the video on each slide to have the students fill out the I Notice / I Wonder table on the handout.
Use the modified Think-Pair-Share instructional strategy to have the students go over the process individually, in pairs, and as a class. Display slide 19 and have the students individually write notes over the process to determine the value of the gravitational constant. Display slide 20 and in pairs, have the students write notes over the process to determine the value of the gravitational constant. Display slide 21 and have a class discussion over the answers to reiterate what needs to be done.
Display slide 22 and have the students finish the remainder of the Finding the Gravitational Constant handout and turn it in.
Evaluate
15 Minute(s)
Display slide 23 and slide 24. Have students individually answer the two questions on notebook paper and turn it in before leaving the classroom for the day. Review students’ papers to assess understanding of the lesson content. See the attached Exit Ticket Solution Key for answers to the questions.
Resources
Aasoka. (n.d.). Determining gravitational constant. https://www.youtube.com/watch?v=4wt0135G8kM&t=38s
Gravity Force Lab. PhET. (n.d.). https://phet.colorado.edu/en/simulations/gravity-force-lab
K20 Center. (n.d.). Justified True or False. Strategies. https://learn.k20center.ou.edu/strategy/174
K20 Center. (n.d.). Card Matching. Strategies. https://learn.k20center.ou.edu/strategy/1837
K20 Center. (n.d.). Sticky Bars. Strategies. https://learn.k20center.ou.edu/strategy/129
K20 Center. (n.d.). Pass The Problem. Strategies. https://learn.k20center.ou.edu/strategy/151
K20 Center. (n.d.). I Notice / I Wonder. Strategies. https://learn.k20center.ou.edu/strategy/180
K20 Center. (n.d.). Think-Pair-Share. Strategies. https://learn.k20center.ou.edu/strategy/139