Simple Machines: Catapults

Retrieved from the Akron Global Polymer Academy at http://www.agpa.uakron.edu/p16/lesson-plans.php

Grades: 5-8
Author: Tracy Wilson, Jason Pitak, Tim Petrie, Jacqueline Godsey, AGPA staff
Source: Original

Abstract

Working in groups, students will be given materials to build and test a catapult. Then, the groups will exchange catapults so the students can improve on another group's design for accuracy and distance.

Objectives

What should the students know as a result of this lesson?

Students will understand how a catapult works
Students will understand the engineering design process
Students will understand that the solution to one problem may create other problems and require refining the original design
Students will understand that the best design may not be feasible because of constraints, such as material availability, cost, or time

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

Students will be able to build a simple catapult
Students will be able to evaluate and improve an existing design
Students will be able to give and receive constructive criticism

Materials

3 rubber bands
2 push pins
Wood block; possibly 3"x 3"x 1"; this block will provide the base of the catapult
1 tongue depressor
1 dosage cup
1 ft strip of masking tape
Acrylic 1/2" or 1" pompoms, to be launched by catapult

Procedures

Engagement

Introduce simple machines to the class by showing the Bill Nye video "Simple Machines part 1" - http://www.youtube.com/watch?v=grWIC9VsFY4.
Have a discussion of the catapults in the video.

Assessment: The assessment is informal. Monitor that the students are watching the video and involved in the discussion following the video. At this time, notice any misconceptions the students may have about catapults.

Exploration

Students will work in groups and use materials provided to build a catapult. Tell the students that they should use all materials provided for the catapult, if possible. Provide the rubric for grading the catapults to the students.
Groups each launch pompoms and create a data table with 3 trials. Data should include the distance and accuracy of the launch.

Assessment: Monitor that the students are using the materials as intended and that the students are recording the data properly.

Explanation

Each group presents their catapult to the class describing the strengths and weaknesses of the catapult.
Explain the engineering design process. Have the students discuss their design process. For the engineering design process see Content Knowledge.

Assessment: Use the rubric provided to evaluate the catapults.

Elaboration

Have the groups exchange catapults.
Groups will modify the design of the catapult that they receive and test the new design. The groups should create a data table with 3 trials. Data should include the distance and accuracy of the launch.

Assessment: Each student should do a short write-up that includes:

The results from the modifications to the catapult.
Suggestions to improve the catapult with additional materials beyond what was provided in this lesson. The students should include an explanation of the expected results with the additional materials based on the experimentation from this lesson.

Prerequisites

An understanding of simple machines is necessary.

Best Teaching Practices

Hands-on Learning
Inquiry Approaches
Real-life Situations and Problem Solving

Alignment with Standards

National Standards:

Science and Technology 5-8
Physical Science 5-8

Ohio Standards:

Grades 6-8: Physical Science Benchmark D
Grades 6-8: Science and Technology Benchmark B

Content Knowledge

Information on simple machines can be found at:
http://atlantis.coe.uh.edu/archive/science/science_lessons/scienceles1/finalhome.htm

http://www.fi.edu/qa97/spotlight3/

Information on the engineering design process can be found at:
http://www.nasa.gov/audience/foreducators/plantgrowth/reference/Eng_Design_5-12.html

Numerous websites can be found on catapults.

Information on potential and kinetic energy can be found at:
http://science.howstuffworks.com/engineering/structural/roller-coaster3.htm

Safety

Safety goggles are necessary.
General science classroom safety should be followed.

Applications

Problem solving skills, working in groups, and accepting constructive criticism are necessary in life. In addition, product development and engineering process design are necessary for students that will pursue careers that need these skills.

Assessment

Assessments are included at each stage of the learning cycle.

Other Considerations

Grouping Suggestions:

At the beginning of the lesson, tell students that they will be trading their catapult with another group and the new group will modify the original design to improve the catapult. Also, explain constructive criticism so the students will understand how to give and receive constructive criticism.

Groups should contain a maximum of 4 students.

Pacing/Suggested Time:

This lesson should take four 45 minute class periods. This will vary based on the number of groups and the length of the discussions on simple machines, engineering design process, potential energy, and kinetic energy.

Printable PDF Worksheets (Click on links below to view and print worksheets)

Simple Machines Data Sheet [PDF]
Simple Machines Rubric [PDF]