Hands-on Activity: Blow-and-Go Parachute

Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

A military skydiver at the AirExpo 2007 air show near Toulouse, France.
Drag slows down a skydiver's descent.
copyright
Copyright © Wikimedia Commons http://commons.wikimedia.org/wiki/File:Skydiver_-_AirExpo_Muret_2007_0240_2007-05-12.jpg

Summary

Students make a skydiver and parachute contraption to demonstrate how drag caused by air resistance slows the descent of skydivers as they travel back to Earth. Gravity pulls the skydiver toward the Earth, while the air trapped by the parachute provides an upward resisting force (drag) on the skydiver.

Engineering Connection

To design safe recreation and transportation vehicles, engineers take into account all forces acting on the object. Sometimes they use the drag force to slow down or control a moving object, for example, in designing a parachute, vehicle brakes or paper moving through a copy machine. Engineers modify their designs to make the forces of thrust, lift, weight and drag smaller or larger, which changes how the object behaves when moving through air or water.

Educational Standards

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All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

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Learning Objectives

A drawing on the left shows a student launching the parachute flier by blowing on a straw under the paper cone. The second drawing shows four examples of falling parachutes, open and slowing the fall of each cone.
Launching the parachutes; how they fall.
copyright
Copyright © Hauser, Jill Frankel. Gizmos and Gadgets: Creating Science Contraptions that Work (and Knowing Why). Charlotte, VT: Williamson Publishing, 1999.
After this activity, students should be able to:

  • Understand which forces act on the skydiver as s/he is going up in the air and is coming back down to the ground.
  • Experimentally identify which geometric shapes most successfully reduce drag
  • Collect data from the experiment and graph the results
  • Understand why engineers need to identify how different forces interact with each other

Materials List

Each group needs:

  • paper
  • 4 paper strips (for decoration) (size: approx. ¾ in. x 3 in.)
  • plastic drinking straws, both jumbo- and regular-sized
  • plastic grocery bag
  • 32 inches of thread

Introduction/Motivation

Forces are invisible interactions that push and pull on things all the time. Even when you're sitting still in a chair, there are forces pushing and pulling on you. For example, the force of gravity pulls you down into the chair, and the force of air pressure helps you breathe. This activity is an investigation of forces — how forces interact, and what we can do to make forces larger and smaller. We'll use air blown through a straw to create forces called thrust and lift. Thrust and lift push our parachute up into the air, but at the same time, a force called weight is pulling the parachute down. Eventually, the parachute stops going up, and starts falling downward. Then the parachute opens up, and a force called drag slows the fall. While you're making your parachute, think about ways we can make the forces of thrust, lift, weight and drag smaller or larger. How will the interactions of these forces change the flight of the parachute?

Procedure

Before the Activity

  • Have the students bring plastic grocery bags from home.
  • Pre-cut strips of paper for the students to use as paper arms and legs.
  • Copy a Flying Forces Worksheet for each student.

With the Students

  1. Ask the students: Has anyone ever seen a skydiver? How does skydiving work? Today we are going to learn more about this.
  2. Roll a quarter sheet of paper into a tight cone 4 inches long and 1½ inches across at its opening. Tape the cone together. Snip the bottom edge even.
  3. Decorate the cone with markers to look like a skydiver.
  4. Tape on folded paper-strip arms and legs.
  5. Seal off one end of a 2½ inch section of a jumbo-sized straw with tape. Tape the section to the inside of the cone with the open end facing outward.
  6. Cut an 8-inch square from the plastic bag to make the canopy.
  7. Cut four 8-inch lengths of thread, and tie or tape one to each corner of the square.
  8. Tie the other ends of the threads together and tape onto the top of the cone.
  9. Insert the narrow straw into the straw section already taped inside the cone. Set the point of the cone at the center of the canopy, so that the canopy drapes gently around the cone. Point the straw to the sky and blow sharply through it.
  10. Allow time for students to complete the activity worksheet.
  11. When they finish, have them check their answers with a peer, giving time for everyone to finish.
  12. Review the worksheets.

Attachments

Safety Issues

Students need to be careful handling scissors.

Remember that the plastic bags can be a choking hazard.

Troubleshooting Tips

Check the plastic bags to make sure they do not have large holes in them.

Be sure to wrap the parachutes around the cones well so they don't come unraveled on the ascent.

Assessment

Pre-Activity Assessment

Discussion Question: Solicit, integrate and summarize student responses.

  • Has anyone ever seen a skydiver? How does skydiving work? (Answer: When a parachute opens up, it slows the diver down. This is an illustration of drag force.)

Activity Embedded Assessment

Worksheet: Have the students complete the activity worksheet; review their answers to gauge their mastery of the subject.

Pairs Check: After students finish working individually on worksheets, have them compare answers with a peer, giving all students time to finish the worksheet.

Post-Activity Assessment

Worksheet Discussion: Review and discuss the worksheet answers with the entire class. Use the answers to gauge students' mastery of the subject.

Activity Extensions

Have the students make different-shaped skydivers and ask them how it affects the flight. (The less aerodynamically shaped the skydiver, the more drag is exerted on the skydiver in flight, decreasing the duration and height of flight).

References

Hauser, Jill Frankel. Gizmos and Gadgets: Creating Science Contraptions that Work (and Knowing Why). Charlotte, VT: Williamson Publishing, 1999.

Contributors

Sabre Duren; Ben Heavner; Malinda Schaefer Zarske; Denise Carlson

Copyright

© 2004 by Regents of the University of Colorado.

Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation GK-12 grant no 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: July 13, 2016

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