Authentic Lessons for 21st Century Learning

The Bigger the Heart, the Bigger the Attraction

Relative Gravity and Gravitational Force

Alonna Smith, Alexandra Parsons | Published: November 9th, 2022 by K20 Center


Building upon students' understanding of gravity, this lesson helps them to determine that gravity is attractive and is correlated with mass and inversely correlative with distance. Rather than using calculations or formulas, students use data and tables to determine whether the provided information about mass, gravity, and distance is correct, which allows them to explore the qualitative nature of those properties.

Essential Question(s)

How do physical properties influence gravitational interactions?



Students respond to a gravity "pick-up line" and are presented with a fact about black holes.


Students conduct a gravity bucket lab.


Students evaluate the truthfulness of several statements about gravity.


Students conduct a comparative analysis of gravity and the planets in our solar system.


Students write a CER statement supporting or refuting a fact about black holes.


  • Lesson Slides (attached)

  • Gravity Bucket Lab handout (attached; one per student)

  • Gravity Bucket Lab Teacher's Guide (attached)

  • Always, Sometimes, or Never True handout (attached; one per group of three students)

  • Always, Sometimes, or Never True Answer Key (attached; optional)

  • Gravity Comparative Analysis handout (attached; one per student)

  • Buckets (3.5 gallon or larger; two per lab group)

  • Stretchy fabric

  • Bungee cords

  • Variety of balls and weights (see Gravity Bucket Lab Teacher's Guide for details)


Use the attached Lesson Slides to guide the lesson. As students enter the classroom, have the Bell Ringer on slide 4 displayed. After reading the phrase, "Even if Earth didn't have gravity, I'd still fall for you," students should take a moment to write down an explanation of why it is funny. After they write down their responses, have a few students share them with the class.

Display slide 5. Show this video that compares the mass of a black hole to the mass of the sun. Let students know that we will answer why this comparison matters at the end of the lesson.


Display slide 6. Organize students into groups of three and pass out a copy of the Gravity Bucket Lab to each student. Make sure each group has all of the materials needed to complete the lab.

Give students time to work through the lab activities and answer the questions on their handouts.

Bring students back together as a class, and use the questions on slide 7 to guide a discussion about the lab.


With their Gravity Bucket Lab handout in hand, have students form new groups of three. These members of these groups should not have worked together on the lab.

Go to slide 8. Pass out an Always, Sometimes, or Never True handout to each group.

Allow students time to use their lab results and their prior knowledge to determine the truthfulness of the statements.

Instruct students to hold on to their handouts, but don't reveal the correct answers yet. Students will revisit their answers to the statements later in the lesson.


Go to slide 9. To connect what they have experienced in the Gravity Buckets lab to real-life values, students will continue working with their groups from the Explain activity to do a comparative analysis of gravity, mass, and distance of our solar system's planets and sun. Pass out copies of the Gravity Comparative Analysis handout for students to work through. Have students refer back to the Engage and Explore activities to help them make connections to the data on their handouts.

After completing the Gravity Comparative Analysis handout, direct students back to their Always, Sometimes, or Never True statements. Ask if what they learned when comparing data has changed any of their answers or provided new examples or non-examples.


Go to slide 18. Replay the video from the Engage section comparing a black hole to the sun.

Ask students to get out a sheet of paper, and then share the following questions on slide 19:

  • Based on what you have learned, what claim can you make about the gravity of a black hole versus the sun?

  • What evidence do you have to support your claim?

  • What reasoning (supporting details or assurance) do you have to support your evidence and claim?

After they've had time to think about these questions, ask students to write a Claim, Evidence. Reasoning (CER) statement that summarizes their answers to the three questions. If students are struggling, prompt them to look back at the data from the Gravity Bucket Lab, the data tables of the planets in the Gravity Comparative Analysis, and their responses to the Always, Sometimes, or Never True statements.

Once students have written their CER statements, they can turn them in for you to use as a formative assessment to determine their understanding of the content and what concepts need additional clarification in future lessons.