Falling Physics

Show students two objects with the same size and shape but with different masses.

Use the turn and talk protocol to Ask & Discuss: A famous experiment was done at the Leaning Tower of Pisa (perhaps show pictures and description for context). Which object do you think would hit the ground first after being dropped from the Leaning Tower of Pisa?

1. Pair students up
2. Give them a minute to think quietly
3. Give students 2 minutes to discuss their thinking
4. Have students record their answers or share out to the whole group

Once students have shared their initial ideas, show a video of the debate between Aristotle and Galileo.

Then have them complete the BEFORE activities in their student manual.

After students share their ideas, first with a partner, then with the class, sort students into two groups: Aristotle and Galileo.

Place the two tart pans on the floor, bottom up, about a foot apart.

Select two equal sized balls.

If you have a beam balance, find the mass of the two balls and write those values on your notes.

Get your timer and camera ready to record your experiment.

Make sure to drop the balls at the same time.

How many bangs did you hear on the tart pans each time you dropped the balls?

Check your slow motion video. Did the video confirm what you heard?

Make experiment groups based on who students agree with (Aristotle or Galileo).

In the student’s guide we have asked the students to design their own experiment to test if two objects of the same mass but different shape hit the ground at the same time. The idea is to encourage them to be creative, to understand how to design experiments, and to think like scientists and engineers. They are given a set of materials that they can use to do their experiments. This is to prompt them, but they should be allowed to use other materials in their design. Make sure you inform students of invisible variables they should control for like drop height, etc.

Slow motion videos of their dropping objects work really well for this experiment.

The goal of the experiment is for students to understand that mass is not a factor that affects how objects fall, that they notice the shape matters and why it matters. Crumpling the paper or changing the direction in which the paper is dropped can support those ideas. They need to figure out which variables they should control for, for example dropping the papers at the same time or the presence of a strong air current, and consistency of the repeated experiments.

After students have had a chance to discuss key ideas from the lesson, you can now clarify and give concise definitions to the forces they experimented with.

Watch the video, Was Aristotle Right? No, he wasn't. And yet, for 1,000 years everyone believed him. But doing the experiment would show you, besides a great view of Pisa, that in fact, both spheres hit the ground at the same time.

This is exactly what Galileo did, showing the world that objects of different masses fall at the same rate. This is also a good example of why it is important to do experiments yourself and not to just take someone else’s word for it.

To start understanding why Galileo was right, we need to understand the difference between several physics words that are often jumbled together and confused: mass, weight, speed, velocity, acceleration, and force.

Think about the experiment we did yesterday, draw, write, or explain our conclusions? Discuss and compare with your elbow partner.

Today, you will have two objects with different mass but similar shapes. What do you think will happen?

Use the Turn and Talk Protocol to have students discuss what their hypothesis will be, then have them write or draw it.

1. Pair students up
2. Give them a minute to think quietly
3. Give students two minutes to discuss their thinking
4. Have students record their answers or share out to the whole group

Take the two pieces of paper and crumple one into a ball.

If you have a beam balance, find the mass of each piece of paper. Write those values in your notes and observations section.

Measure the height from which you will drop the pieces of papers. Make sure it is the same height. Write the height value on your notes and observations section.

Get your timer and camera ready for recording.

Drop the pieces of paper at the same time.

Make sure students are put into intentional groups. See above.

Students will complete the experiment using the student guide where we have outlined the experiment for students and along the way, they record results and answer questions.

In the student guide, they will answer questions that help them understand what rust does to objects.

Continue to listen in on each group’s discussion, answer as few questions as possible. Even if a group is off a little, they will have a chance to work out these stuck points later.

Use the All Class Science-Talk to discuss the question: Does mass affect the rate of a falling object? Why or why not?

1. The teacher poses a question for students to answer.
2. If necessary, give students time to think or write.
3. The teacher asks students to turn their bodies toward the center of the room for a Science Talk.
4. The teacher explains:
5. “In a Science Talk, knowledge is held by your fellow scientists, and you should talk to each other. The goal of a Science Talk is to help each other understand a phenomenon. You can help your fellow scientists understand by: sharing results, using data, being as clear as possible, and listening carefully to deeply understand what your fellow scientists are saying.
6. Teacher facilitates the student discussion by using Michaels and O’Connor’s Talk Science Primer and avoiding telling answers or asking closed-ended questions.
7. Optional: At the end of the Science Talk, students can record their thinking.