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# Lesson Plans

## Jungle Gym Drop

Grades: 3-5
Author: Michele Deacon, Beth Kennedy, Roberta Gangl, Susan Franz, Chris Bode, Kathie Owens
Source: Frank Potter's Science Gems (internet site)

#### Abstract

Through several trials of dropping objects from various levels of a jungle-gym, students will be able to find out more about gravity, forces, and motion.

#### Objectives

What should students know as a result of this lesson?

• Students will describe the forces that directly affect objects and their motion.

What should the students be able to do as a result of this lesson?

• Students will observe, measure, and collect data.
• Students will organize and evaluate their observations and measurements.
• Students will communicate the results of their investigations.

#### Materials

• Variety of spherical objects
• Meter tape measure
• Stopwatches and rulers (one per group of three)
• Science log books or journals for recording data
• Jungle gym climber
• Vinyl gutter
• Several large piles of soft sand around the base of the jungle gym
• Small tools for raking the landing sites between drops
• Goggles for the student who is raking the sand pile(s)

#### Procedures

Engagement

Review the meaning of a hypothesis as an educated guess based on previous experience. To get the students ready to formulate a hypothesis, have them take a few minutes to think about what has happened to objects they have dropped in the past. Be sure to emphasize to students that it is perfectly all right to make an incorrect hypothesis and that scientists do this all the time. Brainstorm a class hypothesis about what controls how objects will move when dropped. Do not have a lengthy discussion about "gravity" at this point. The focus of the lesson at this point is the experimental process.

Before going out to the playground, pose some of the following questions for students to begin thinking about: What makes things fall when you drop them? Do heavy objects seem to fall faster, slower or the same speed as lighter objects? How does the distance dropped affect the fall and the landing? Would an elephant fall differently than a peanut?

Posed problem: Describe the motion of falling objects: how long does it take objects to hit the ground when dropped from the same height? Describe the crater made in soft sand when the object hits the ground: how wide and how deep is the crater?

Assessment: Monitor the class discussion to be sure that students have some knowledge of making hypotheses and understand the posed problem.

Explanation

Distribute one experiment report to each group of students. Have the student groups select three objects to be dropped. Explain to the students that their three objects should vary in size, shape and mass. Students should then record their selected objects in the appropriate column of their table and make a hypothesis about the nature of the fall and the relative size of the crater they think will be produced. Take students out to the jungle-gym area where the teacher has prepared the landing areas with large piles of soft sand. We suggest that more than one landing area is used so that more than one group may conduct their tests at a time. We also suggest that a drop of at least 2 meters should be used. Releasing from a greater height is more easily measured.

Take turns allowing the investigator in each group the opportunity to drop its objects one at a time. Have the timer take the time of landing and measure the width and depth of the crater formed. Before the next drop happens the landing area will need to be smoothed out. We suggest allowing the students to switch roles, unless a student does not like climbing to the top of the jungle gym.

Assessment: Monitor the students as they perform the tests and collect data. Be sure that they are on task and working safely. Monitor the discussion for signs of data analysis and links to force, motion, and gravity.

Elaboration

Pose a new problem for the students. Ask them to predict the motion and impact on the ground of several objects used in the lesson if the motion is adjusted from a straight vertical drop to a slide down a gutter used like an inclined plane. Return to the playground and conduct a demonstration using this new set up. Back in the classroom discuss the findings within the context of motion, forces and gravity.

Assessment: Show students objects similar to, but not identical to, the objects used in this experiment. Have students predict the fall (time and motion) and the crater formed in the sand pile upon impact. Using their findings from the experiment they should be able to accurately justify their predictions. Ideally their writings should show understanding of gravity, motion, and forces.

#### Prerequisites

Have students think about some objects they might have at school or at home to test how different objects fall when they are dropped. Remind students to pick objects that are different sizes, shapes and masses and that the objects they select will not break.

#### Best Teaching Practices

• Inquiry Approach
• Journal Writing
• Hands-on/Minds-on Learning

#### Alignment with Standards

NGSS Standards:

• 3-PS2-1 Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object.
• 4-PS3-3 Ask questions and predict outcomes about the changes in energy that occur when objects collide.
• 5-PS2-1 Support an argument that the gravitational force exerted by the earth on objects is directed down.

National Standards:

• Content Standard B: K-4 Physical Science

Ohio Standards:

• Grades 3-5 Physical Sciences Benchmark C
• Grades 3-5 Scientific Inquiry Benchmark A
• Grades 3-5 Scientific Inquiry Benchmark B
• Grades 3-5 Scientific Inquiry Benchmark C

#### Content Knowledge

• Gravity is the force that pulls all objects to Earth.
• When the only force acting on a falling object is gravity, the object is said to be in free fall. An object in free fall accelerates as it falls. All objects in free fall accelerate at the same rate regardless of mass.
• Objects that fall through air experience a type of friction called air resistance. In a vacuum where there is no air, objects fall with the same rate of acceleration. As a falling object speeds up, the air resistance against it increases.
• Newton's second Law of Motion states that an object's weight is equal to its mass multiplied by the acceleration due to gravity.
• Numerous examples of the interaction of gravity, force, and motion exist: sky divers, autumn leaves falling to the ground, Newton's apple, planets and the Sun, to name a few.

#### Safety

Exercise caution when climbing to the top of the jungle gym. Do not allow students to stand too close to the falling objects or to the sand pile into which they drop. Pick objects to drop that are sturdy with no possibility of shattering upon impact. The student(s) raking the sand pile(s) should wear goggles.

#### Applications

Gravity affects our everyday lives.

#### Assessment

Show students objects similar to, but not identical to, the objects used in this experiment. Have students predict the fall (time and motion) and the crater formed in the sand pile upon impact. Using their findings from the experiment they should be able to accurately justify their predictions. Ideally their writings should show understanding of gravity, motion, and forces.

#### Other Considerations

Grouping Suggestions: Groups of three. Students take turns being investigator, timer, and recorder.

Pacing/Suggested Time: 2 Science periods.

#### Printable PDF Worksheets

Grading Card Checklist